Merge branch 'master' into ipt-udp-matchers

54 files changed, 63 insertions, 2316 deletions

diff --git a/pkg/sentry/platform/BUILD b/pkg/sentry/platform/BUILD
index 157bffa81..453241eca 100644
--- a/pkg/sentry/platform/BUILD
+++ b/pkg/sentry/platform/BUILD
@@ -1,5 +1,5 @@
+load("//tools:defs.bzl", "go_library")
 load("//tools/go_generics:defs.bzl", "go_template_instance")
-load("//tools/go_stateify:defs.bzl", "go_library")
 
 package(licenses = ["notice"])
 
@@ -22,19 +22,18 @@ go_library(
         "mmap_min_addr.go",
         "platform.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform",
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
         "//pkg/atomicbitops",
+        "//pkg/context",
         "//pkg/log",
+        "//pkg/safecopy",
+        "//pkg/safemem",
         "//pkg/seccomp",
         "//pkg/sentry/arch",
-        "//pkg/sentry/context",
-        "//pkg/sentry/platform/safecopy",
-        "//pkg/sentry/safemem",
         "//pkg/sentry/usage",
-        "//pkg/sentry/usermem",
         "//pkg/syserror",
+        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/platform/context.go b/pkg/sentry/platform/context.go
index e29bc4485..6759cda65 100644
--- a/pkg/sentry/platform/context.go
+++ b/pkg/sentry/platform/context.go
@@ -15,7 +15,7 @@
 package platform
 
 import (
-	"gvisor.dev/gvisor/pkg/sentry/context"
+	"gvisor.dev/gvisor/pkg/context"
 )
 
 // contextID is the auth package's type for context.Context.Value keys.
diff --git a/pkg/sentry/platform/interrupt/BUILD b/pkg/sentry/platform/interrupt/BUILD
index 85e882df9..83b385f14 100644
--- a/pkg/sentry/platform/interrupt/BUILD
+++ b/pkg/sentry/platform/interrupt/BUILD
@@ -1,5 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools:defs.bzl", "go_library", "go_test")
 
 package(licenses = ["notice"])
 
@@ -8,7 +7,6 @@ go_library(
     srcs = [
         "interrupt.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/interrupt",
     visibility = ["//pkg/sentry:internal"],
     deps = ["//pkg/sync"],
 )
@@ -17,5 +15,5 @@ go_test(
     name = "interrupt_test",
     size = "small",
     srcs = ["interrupt_test.go"],
-    embed = [":interrupt"],
+    library = ":interrupt",
 )
diff --git a/pkg/sentry/platform/kvm/BUILD b/pkg/sentry/platform/kvm/BUILD
index 6a358d1d4..159f7eafd 100644
--- a/pkg/sentry/platform/kvm/BUILD
+++ b/pkg/sentry/platform/kvm/BUILD
@@ -1,5 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
+load("//tools:defs.bzl", "go_library", "go_test")
 
 package(licenses = ["notice"])
 
@@ -38,7 +37,6 @@ go_library(
         "physical_map_arm64.go",
         "virtual_map.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/kvm",
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/abi/linux",
@@ -46,16 +44,16 @@ go_library(
         "//pkg/cpuid",
         "//pkg/log",
         "//pkg/procid",
+        "//pkg/safecopy",
         "//pkg/seccomp",
         "//pkg/sentry/arch",
         "//pkg/sentry/platform",
         "//pkg/sentry/platform/interrupt",
         "//pkg/sentry/platform/ring0",
         "//pkg/sentry/platform/ring0/pagetables",
-        "//pkg/sentry/platform/safecopy",
         "//pkg/sentry/time",
-        "//pkg/sentry/usermem",
         "//pkg/sync",
+        "//pkg/usermem",
     ],
 )
 
@@ -65,7 +63,7 @@ go_test(
         "kvm_test.go",
         "virtual_map_test.go",
     ],
-    embed = [":kvm"],
+    library = ":kvm",
     tags = [
         "manual",
         "nogotsan",
@@ -77,6 +75,6 @@ go_test(
         "//pkg/sentry/platform/kvm/testutil",
         "//pkg/sentry/platform/ring0",
         "//pkg/sentry/platform/ring0/pagetables",
-        "//pkg/sentry/usermem",
+        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/platform/kvm/address_space.go b/pkg/sentry/platform/kvm/address_space.go
index a25f3c449..be213bfe8 100644
--- a/pkg/sentry/platform/kvm/address_space.go
+++ b/pkg/sentry/platform/kvm/address_space.go
@@ -20,8 +20,8 @@ import (
 	"gvisor.dev/gvisor/pkg/atomicbitops"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // dirtySet tracks vCPUs for invalidation.
diff --git a/pkg/sentry/platform/kvm/bluepill.go b/pkg/sentry/platform/kvm/bluepill.go
index 30dbb74d6..35cd55fef 100644
--- a/pkg/sentry/platform/kvm/bluepill.go
+++ b/pkg/sentry/platform/kvm/bluepill.go
@@ -19,9 +19,9 @@ import (
 	"reflect"
 	"syscall"
 
+	"gvisor.dev/gvisor/pkg/safecopy"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
-	"gvisor.dev/gvisor/pkg/sentry/platform/safecopy"
 )
 
 // bluepill enters guest mode.
diff --git a/pkg/sentry/platform/kvm/bluepill_fault.go b/pkg/sentry/platform/kvm/bluepill_fault.go
index f6459cda9..e34f46aeb 100644
--- a/pkg/sentry/platform/kvm/bluepill_fault.go
+++ b/pkg/sentry/platform/kvm/bluepill_fault.go
@@ -18,7 +18,7 @@ import (
 	"sync/atomic"
 	"syscall"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 const (
diff --git a/pkg/sentry/platform/kvm/context.go b/pkg/sentry/platform/kvm/context.go
index 99450d22d..c769ac7b4 100644
--- a/pkg/sentry/platform/kvm/context.go
+++ b/pkg/sentry/platform/kvm/context.go
@@ -19,7 +19,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/interrupt"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // context is an implementation of the platform context.
diff --git a/pkg/sentry/platform/kvm/kvm.go b/pkg/sentry/platform/kvm/kvm.go
index d337c5c7c..972ba85c3 100644
--- a/pkg/sentry/platform/kvm/kvm.go
+++ b/pkg/sentry/platform/kvm/kvm.go
@@ -23,8 +23,8 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // KVM represents a lightweight VM context.
diff --git a/pkg/sentry/platform/kvm/kvm_test.go b/pkg/sentry/platform/kvm/kvm_test.go
index 30df725d4..c42752d50 100644
--- a/pkg/sentry/platform/kvm/kvm_test.go
+++ b/pkg/sentry/platform/kvm/kvm_test.go
@@ -27,7 +27,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/kvm/testutil"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var dummyFPState = (*byte)(arch.NewFloatingPointData())
diff --git a/pkg/sentry/platform/kvm/machine.go b/pkg/sentry/platform/kvm/machine.go
index e6d912168..8076c7529 100644
--- a/pkg/sentry/platform/kvm/machine.go
+++ b/pkg/sentry/platform/kvm/machine.go
@@ -25,8 +25,8 @@ import (
 	"gvisor.dev/gvisor/pkg/procid"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // machine contains state associated with the VM as a whole.
diff --git a/pkg/sentry/platform/kvm/machine_amd64.go b/pkg/sentry/platform/kvm/machine_amd64.go
index 873e39dc7..923ce3909 100644
--- a/pkg/sentry/platform/kvm/machine_amd64.go
+++ b/pkg/sentry/platform/kvm/machine_amd64.go
@@ -26,7 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // initArchState initializes architecture-specific state.
diff --git a/pkg/sentry/platform/kvm/machine_arm64.go b/pkg/sentry/platform/kvm/machine_arm64.go
index 3b1f20219..09552837a 100644
--- a/pkg/sentry/platform/kvm/machine_arm64.go
+++ b/pkg/sentry/platform/kvm/machine_arm64.go
@@ -20,7 +20,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type vCPUArchState struct {
diff --git a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
index 3f2f97a6b..1c8384e6b 100644
--- a/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
+++ b/pkg/sentry/platform/kvm/machine_arm64_unsafe.go
@@ -26,7 +26,7 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // setMemoryRegion initializes a region.
diff --git a/pkg/sentry/platform/kvm/physical_map.go b/pkg/sentry/platform/kvm/physical_map.go
index 91de5dab1..f7fa2f98d 100644
--- a/pkg/sentry/platform/kvm/physical_map.go
+++ b/pkg/sentry/platform/kvm/physical_map.go
@@ -21,7 +21,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/log"
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type region struct {
diff --git a/pkg/sentry/platform/kvm/testutil/BUILD b/pkg/sentry/platform/kvm/testutil/BUILD
index b0e45f159..f7605df8a 100644
--- a/pkg/sentry/platform/kvm/testutil/BUILD
+++ b/pkg/sentry/platform/kvm/testutil/BUILD
@@ -1,4 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library")
 
 package(licenses = ["notice"])
 
@@ -12,6 +12,5 @@ go_library(
         "testutil_arm64.go",
         "testutil_arm64.s",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/kvm/testutil",
     visibility = ["//pkg/sentry/platform/kvm:__pkg__"],
 )
diff --git a/pkg/sentry/platform/kvm/virtual_map.go b/pkg/sentry/platform/kvm/virtual_map.go
index 2d68855ef..c8897d34f 100644
--- a/pkg/sentry/platform/kvm/virtual_map.go
+++ b/pkg/sentry/platform/kvm/virtual_map.go
@@ -22,7 +22,7 @@ import (
 	"regexp"
 	"strconv"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type virtualRegion struct {
diff --git a/pkg/sentry/platform/kvm/virtual_map_test.go b/pkg/sentry/platform/kvm/virtual_map_test.go
index 6a2f145be..327e2be4f 100644
--- a/pkg/sentry/platform/kvm/virtual_map_test.go
+++ b/pkg/sentry/platform/kvm/virtual_map_test.go
@@ -18,7 +18,7 @@ import (
 	"syscall"
 	"testing"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type checker struct {
diff --git a/pkg/sentry/platform/mmap_min_addr.go b/pkg/sentry/platform/mmap_min_addr.go
index 999787462..091c2e365 100644
--- a/pkg/sentry/platform/mmap_min_addr.go
+++ b/pkg/sentry/platform/mmap_min_addr.go
@@ -20,7 +20,7 @@ import (
 	"strconv"
 	"strings"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // systemMMapMinAddrSource is the source file.
diff --git a/pkg/sentry/platform/platform.go b/pkg/sentry/platform/platform.go
index ec22dbf87..2ca696382 100644
--- a/pkg/sentry/platform/platform.go
+++ b/pkg/sentry/platform/platform.go
@@ -22,10 +22,10 @@ import (
 	"os"
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
+	"gvisor.dev/gvisor/pkg/safemem"
 	"gvisor.dev/gvisor/pkg/seccomp"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
-	"gvisor.dev/gvisor/pkg/sentry/safemem"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // Platform provides abstractions for execution contexts (Context,
diff --git a/pkg/sentry/platform/ptrace/BUILD b/pkg/sentry/platform/ptrace/BUILD
index cd13390c3..95abd321e 100644
--- a/pkg/sentry/platform/ptrace/BUILD
+++ b/pkg/sentry/platform/ptrace/BUILD
@@ -1,4 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library")
 
 package(licenses = ["notice"])
 
@@ -20,20 +20,19 @@ go_library(
         "subprocess_linux_unsafe.go",
         "subprocess_unsafe.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/ptrace",
     visibility = ["//:sandbox"],
     deps = [
         "//pkg/abi/linux",
         "//pkg/log",
         "//pkg/procid",
+        "//pkg/safecopy",
         "//pkg/seccomp",
         "//pkg/sentry/arch",
         "//pkg/sentry/hostcpu",
         "//pkg/sentry/platform",
         "//pkg/sentry/platform/interrupt",
-        "//pkg/sentry/platform/safecopy",
-        "//pkg/sentry/usermem",
         "//pkg/sync",
+        "//pkg/usermem",
         "@org_golang_x_sys//unix:go_default_library",
     ],
 )
diff --git a/pkg/sentry/platform/ptrace/ptrace.go b/pkg/sentry/platform/ptrace/ptrace.go
index bb0e03880..03adb624b 100644
--- a/pkg/sentry/platform/ptrace/ptrace.go
+++ b/pkg/sentry/platform/ptrace/ptrace.go
@@ -51,8 +51,8 @@ import (
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
 	"gvisor.dev/gvisor/pkg/sentry/platform/interrupt"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var (
diff --git a/pkg/sentry/platform/ptrace/ptrace_unsafe.go b/pkg/sentry/platform/ptrace/ptrace_unsafe.go
index 72c7ec564..6c0ed7b3e 100644
--- a/pkg/sentry/platform/ptrace/ptrace_unsafe.go
+++ b/pkg/sentry/platform/ptrace/ptrace_unsafe.go
@@ -20,7 +20,7 @@ import (
 
 	"gvisor.dev/gvisor/pkg/abi/linux"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // getRegs gets the general purpose register set.
diff --git a/pkg/sentry/platform/ptrace/stub_unsafe.go b/pkg/sentry/platform/ptrace/stub_unsafe.go
index aa1b87237..341dde143 100644
--- a/pkg/sentry/platform/ptrace/stub_unsafe.go
+++ b/pkg/sentry/platform/ptrace/stub_unsafe.go
@@ -19,8 +19,8 @@ import (
 	"syscall"
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/sentry/platform/safecopy"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/safecopy"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // stub is defined in arch-specific assembly.
diff --git a/pkg/sentry/platform/ptrace/subprocess.go b/pkg/sentry/platform/ptrace/subprocess.go
index 15dc46a5b..31b7cec53 100644
--- a/pkg/sentry/platform/ptrace/subprocess.go
+++ b/pkg/sentry/platform/ptrace/subprocess.go
@@ -25,8 +25,8 @@ import (
 	"gvisor.dev/gvisor/pkg/procid"
 	"gvisor.dev/gvisor/pkg/sentry/arch"
 	"gvisor.dev/gvisor/pkg/sentry/platform"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
 	"gvisor.dev/gvisor/pkg/sync"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // Linux kernel errnos which "should never be seen by user programs", but will
diff --git a/pkg/sentry/platform/ring0/BUILD b/pkg/sentry/platform/ring0/BUILD
index 87f4552b5..934b6fbcd 100644
--- a/pkg/sentry/platform/ring0/BUILD
+++ b/pkg/sentry/platform/ring0/BUILD
@@ -1,4 +1,4 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library")
 load("//tools/go_generics:defs.bzl", "go_template", "go_template_instance")
 
 package(licenses = ["notice"])
@@ -74,11 +74,10 @@ go_library(
         "lib_arm64.s",
         "ring0.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/ring0",
     visibility = ["//pkg/sentry:internal"],
     deps = [
         "//pkg/cpuid",
         "//pkg/sentry/platform/ring0/pagetables",
-        "//pkg/sentry/usermem",
+        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/platform/ring0/defs_amd64.go b/pkg/sentry/platform/ring0/defs_amd64.go
index 9dae0dccb..9c6c2cf5c 100644
--- a/pkg/sentry/platform/ring0/defs_amd64.go
+++ b/pkg/sentry/platform/ring0/defs_amd64.go
@@ -18,7 +18,7 @@ package ring0
 
 import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var (
diff --git a/pkg/sentry/platform/ring0/defs_arm64.go b/pkg/sentry/platform/ring0/defs_arm64.go
index a850ce6cf..1583dda12 100644
--- a/pkg/sentry/platform/ring0/defs_arm64.go
+++ b/pkg/sentry/platform/ring0/defs_arm64.go
@@ -18,7 +18,7 @@ package ring0
 
 import (
 	"gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables"
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 var (
diff --git a/pkg/sentry/platform/ring0/entry_arm64.go b/pkg/sentry/platform/ring0/entry_arm64.go
index 0dfa42c36..62a93f3d6 100644
--- a/pkg/sentry/platform/ring0/entry_arm64.go
+++ b/pkg/sentry/platform/ring0/entry_arm64.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Google Inc.
+// Copyright 2019 The gVisor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/pkg/sentry/platform/ring0/gen_offsets/BUILD b/pkg/sentry/platform/ring0/gen_offsets/BUILD
index 42076fb04..4cae10459 100644
--- a/pkg/sentry/platform/ring0/gen_offsets/BUILD
+++ b/pkg/sentry/platform/ring0/gen_offsets/BUILD
@@ -1,4 +1,4 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_binary")
+load("//tools:defs.bzl", "go_binary")
 load("//tools/go_generics:defs.bzl", "go_template_instance")
 
 package(licenses = ["notice"])
@@ -28,6 +28,6 @@ go_binary(
     deps = [
         "//pkg/cpuid",
         "//pkg/sentry/platform/ring0/pagetables",
-        "//pkg/sentry/usermem",
+        "//pkg/usermem",
     ],
 )
diff --git a/pkg/sentry/platform/ring0/kernel_arm64.go b/pkg/sentry/platform/ring0/kernel_arm64.go
index ed82a131e..c3d341998 100644
--- a/pkg/sentry/platform/ring0/kernel_arm64.go
+++ b/pkg/sentry/platform/ring0/kernel_arm64.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Google Inc.
+// Copyright 2019 The gVisor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/pkg/sentry/platform/ring0/lib_arm64.go b/pkg/sentry/platform/ring0/lib_arm64.go
index 8bcfe1032..af075aae4 100644
--- a/pkg/sentry/platform/ring0/lib_arm64.go
+++ b/pkg/sentry/platform/ring0/lib_arm64.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Google Inc.
+// Copyright 2019 The gVisor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/pkg/sentry/platform/ring0/offsets_arm64.go b/pkg/sentry/platform/ring0/offsets_arm64.go
index cd2a65f97..8c960c749 100644
--- a/pkg/sentry/platform/ring0/offsets_arm64.go
+++ b/pkg/sentry/platform/ring0/offsets_arm64.go
@@ -1,4 +1,4 @@
-// Copyright 2019 Google Inc.
+// Copyright 2019 The gVisor Authors.
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
diff --git a/pkg/sentry/platform/ring0/pagetables/BUILD b/pkg/sentry/platform/ring0/pagetables/BUILD
index 387a7f6c3..971eed7fa 100644
--- a/pkg/sentry/platform/ring0/pagetables/BUILD
+++ b/pkg/sentry/platform/ring0/pagetables/BUILD
@@ -1,17 +1,14 @@
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-load("//tools/go_stateify:defs.bzl", "go_library")
+load("//tools:defs.bzl", "go_library", "go_test", "select_arch")
 load("//tools/go_generics:defs.bzl", "go_template", "go_template_instance")
 
 package(licenses = ["notice"])
 
-config_setting(
-    name = "aarch64",
-    constraint_values = ["@bazel_tools//platforms:aarch64"],
-)
-
 go_template(
     name = "generic_walker",
-    srcs = ["walker_amd64.go"],
+    srcs = select_arch(
+        amd64 = ["walker_amd64.go"],
+        arm64 = ["walker_amd64.go"],
+    ),
     opt_types = [
         "Visitor",
     ],
@@ -91,14 +88,13 @@ go_library(
         "walker_map.go",
         "walker_unmap.go",
     ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/ring0/pagetables",
     visibility = [
         "//pkg/sentry/platform/kvm:__subpackages__",
         "//pkg/sentry/platform/ring0:__subpackages__",
     ],
     deps = [
-        "//pkg/sentry/usermem",
         "//pkg/sync",
+        "//pkg/usermem",
     ],
 )
 
@@ -111,6 +107,6 @@ go_test(
         "pagetables_test.go",
         "walker_check.go",
     ],
-    embed = [":pagetables"],
-    deps = ["//pkg/sentry/usermem"],
+    library = ":pagetables",
+    deps = ["//pkg/usermem"],
 )
diff --git a/pkg/sentry/platform/ring0/pagetables/allocator_unsafe.go b/pkg/sentry/platform/ring0/pagetables/allocator_unsafe.go
index a90394a33..d08bfdeb3 100644
--- a/pkg/sentry/platform/ring0/pagetables/allocator_unsafe.go
+++ b/pkg/sentry/platform/ring0/pagetables/allocator_unsafe.go
@@ -17,7 +17,7 @@ package pagetables
 import (
 	"unsafe"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // newAlignedPTEs returns a set of aligned PTEs.
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables.go b/pkg/sentry/platform/ring0/pagetables/pagetables.go
index 30c64a372..87e88e97d 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables.go
@@ -21,7 +21,7 @@
 package pagetables
 
 import (
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // PageTables is a set of page tables.
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go b/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go
index e78424766..78510ebed 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables_aarch64.go
@@ -19,7 +19,7 @@ package pagetables
 import (
 	"sync/atomic"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // archPageTables is architecture-specific data.
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_amd64_test.go b/pkg/sentry/platform/ring0/pagetables/pagetables_amd64_test.go
index 35e917526..54e8e554f 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables_amd64_test.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables_amd64_test.go
@@ -19,7 +19,7 @@ package pagetables
 import (
 	"testing"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 func Test2MAnd4K(t *testing.T) {
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_arm64_test.go b/pkg/sentry/platform/ring0/pagetables/pagetables_arm64_test.go
index 254116233..2f73d424f 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables_arm64_test.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables_arm64_test.go
@@ -19,7 +19,7 @@ package pagetables
 import (
 	"testing"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 func Test2MAnd4K(t *testing.T) {
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_test.go b/pkg/sentry/platform/ring0/pagetables/pagetables_test.go
index 6e95ad2b9..5c88d087d 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables_test.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables_test.go
@@ -17,7 +17,7 @@ package pagetables
 import (
 	"testing"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 type mapping struct {
diff --git a/pkg/sentry/platform/ring0/pagetables/pagetables_x86.go b/pkg/sentry/platform/ring0/pagetables/pagetables_x86.go
index 3e2383c5e..dcf061df9 100644
--- a/pkg/sentry/platform/ring0/pagetables/pagetables_x86.go
+++ b/pkg/sentry/platform/ring0/pagetables/pagetables_x86.go
@@ -19,7 +19,7 @@ package pagetables
 import (
 	"sync/atomic"
 
-	"gvisor.dev/gvisor/pkg/sentry/usermem"
+	"gvisor.dev/gvisor/pkg/usermem"
 )
 
 // archPageTables is architecture-specific data.
diff --git a/pkg/sentry/platform/safecopy/BUILD b/pkg/sentry/platform/safecopy/BUILD
deleted file mode 100644
index 6769cd0a5..000000000
--- a/pkg/sentry/platform/safecopy/BUILD
+++ /dev/null
@@ -1,31 +0,0 @@
-load("//tools/go_stateify:defs.bzl", "go_library")
-load("@io_bazel_rules_go//go:def.bzl", "go_test")
-
-package(licenses = ["notice"])
-
-go_library(
-    name = "safecopy",
-    srcs = [
-        "atomic_amd64.s",
-        "atomic_arm64.s",
-        "memclr_amd64.s",
-        "memclr_arm64.s",
-        "memcpy_amd64.s",
-        "memcpy_arm64.s",
-        "safecopy.go",
-        "safecopy_unsafe.go",
-        "sighandler_amd64.s",
-        "sighandler_arm64.s",
-    ],
-    importpath = "gvisor.dev/gvisor/pkg/sentry/platform/safecopy",
-    visibility = ["//pkg/sentry:internal"],
-    deps = ["//pkg/syserror"],
-)
-
-go_test(
-    name = "safecopy_test",
-    srcs = [
-        "safecopy_test.go",
-    ],
-    embed = [":safecopy"],
-)
diff --git a/pkg/sentry/platform/safecopy/LICENSE b/pkg/sentry/platform/safecopy/LICENSE
deleted file mode 100644
index 6a66aea5e..000000000
--- a/pkg/sentry/platform/safecopy/LICENSE
+++ /dev/null
@@ -1,27 +0,0 @@
-Copyright (c) 2009 The Go Authors. All rights reserved.
-
-Redistribution and use in source and binary forms, with or without
-modification, are permitted provided that the following conditions are
-met:
-
-   * Redistributions of source code must retain the above copyright
-notice, this list of conditions and the following disclaimer.
-   * Redistributions in binary form must reproduce the above
-copyright notice, this list of conditions and the following disclaimer
-in the documentation and/or other materials provided with the
-distribution.
-   * Neither the name of Google Inc. nor the names of its
-contributors may be used to endorse or promote products derived from
-this software without specific prior written permission.
-
-THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/pkg/sentry/platform/safecopy/atomic_amd64.s b/pkg/sentry/platform/safecopy/atomic_amd64.s
deleted file mode 100644
index a0cd78f33..000000000
--- a/pkg/sentry/platform/safecopy/atomic_amd64.s
+++ /dev/null
@@ -1,136 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "textflag.h"
-
-// handleSwapUint32Fault returns the value stored in DI. Control is transferred
-// to it when swapUint32 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in DI.
-//
-// It must have the same frame configuration as swapUint32 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleSwapUint32Fault(SB), NOSPLIT, $0-24
-  MOVL DI, sig+20(FP)
-  RET
-
-// swapUint32 atomically stores new into *addr and returns (the previous *addr
-// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the
-// value of old is unspecified, and sig is the number of the signal that was
-// received.
-//
-// Preconditions: addr must be aligned to a 4-byte boundary.
-//
-//func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32)
-TEXT ·swapUint32(SB), NOSPLIT, $0-24
-  // Store 0 as the returned signal number. If we run to completion,
-  // this is the value the caller will see; if a signal is received,
-  // handleSwapUint32Fault will store a different value in this address.
-  MOVL $0, sig+20(FP)
-
-  MOVQ addr+0(FP), DI
-  MOVL new+8(FP), AX
-  XCHGL AX, 0(DI)
-  MOVL AX, old+16(FP)
-  RET
-
-// handleSwapUint64Fault returns the value stored in DI. Control is transferred
-// to it when swapUint64 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in DI.
-//
-// It must have the same frame configuration as swapUint64 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleSwapUint64Fault(SB), NOSPLIT, $0-28
-  MOVL DI, sig+24(FP)
-  RET
-
-// swapUint64 atomically stores new into *addr and returns (the previous *addr
-// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the
-// value of old is unspecified, and sig is the number of the signal that was
-// received.
-//
-// Preconditions: addr must be aligned to a 8-byte boundary.
-//
-//func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32)
-TEXT ·swapUint64(SB), NOSPLIT, $0-28
-  // Store 0 as the returned signal number. If we run to completion,
-  // this is the value the caller will see; if a signal is received,
-  // handleSwapUint64Fault will store a different value in this address.
-  MOVL $0, sig+24(FP)
-
-  MOVQ addr+0(FP), DI
-  MOVQ new+8(FP), AX
-  XCHGQ AX, 0(DI)
-  MOVQ AX, old+16(FP)
-  RET
-
-// handleCompareAndSwapUint32Fault returns the value stored in DI. Control is
-// transferred to it when swapUint64 below receives SIGSEGV or SIGBUS, with the
-// signal number stored in DI.
-//
-// It must have the same frame configuration as compareAndSwapUint32 so that it
-// can undo any potential call frame set up by the assembler.
-TEXT handleCompareAndSwapUint32Fault(SB), NOSPLIT, $0-24
-  MOVL DI, sig+20(FP)
-  RET
-
-// compareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns
-// (the value previously stored at addr, 0). If a SIGSEGV or SIGBUS signal is
-// received during the operation, the value of prev is unspecified, and sig is
-// the number of the signal that was received.
-//
-// Preconditions: addr must be aligned to a 4-byte boundary.
-//
-//func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32)
-TEXT ·compareAndSwapUint32(SB), NOSPLIT, $0-24
-  // Store 0 as the returned signal number. If we run to completion, this is
-  // the value the caller will see; if a signal is received,
-  // handleCompareAndSwapUint32Fault will store a different value in this
-  // address.
-  MOVL $0, sig+20(FP)
-
-  MOVQ addr+0(FP), DI
-  MOVL old+8(FP), AX
-  MOVL new+12(FP), DX
-  LOCK
-  CMPXCHGL DX, 0(DI)
-  MOVL AX, prev+16(FP)
-  RET
-
-// handleLoadUint32Fault returns the value stored in DI. Control is transferred
-// to it when LoadUint32 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in DI.
-//
-// It must have the same frame configuration as loadUint32 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleLoadUint32Fault(SB), NOSPLIT, $0-16
-  MOVL DI, sig+12(FP)
-  RET
-
-// loadUint32 atomically loads *addr and returns it. If a SIGSEGV or SIGBUS
-// signal is received, the value returned is unspecified, and sig is the number
-// of the signal that was received.
-//
-// Preconditions: addr must be aligned to a 4-byte boundary.
-//
-//func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32)
-TEXT ·loadUint32(SB), NOSPLIT, $0-16
-  // Store 0 as the returned signal number. If we run to completion,
-  // this is the value the caller will see; if a signal is received,
-  // handleLoadUint32Fault will store a different value in this address.
-  MOVL $0, sig+12(FP)
-
-  MOVQ addr+0(FP), AX
-  MOVL (AX), BX
-  MOVL BX, val+8(FP)
-  RET
diff --git a/pkg/sentry/platform/safecopy/atomic_arm64.s b/pkg/sentry/platform/safecopy/atomic_arm64.s
deleted file mode 100644
index d58ed71f7..000000000
--- a/pkg/sentry/platform/safecopy/atomic_arm64.s
+++ /dev/null
@@ -1,126 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "textflag.h"
-
-// handleSwapUint32Fault returns the value stored in R1. Control is transferred
-// to it when swapUint32 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in R1.
-//
-// It must have the same frame configuration as swapUint32 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleSwapUint32Fault(SB), NOSPLIT, $0-24
-	MOVW R1, sig+20(FP)
-	RET
-
-// See the corresponding doc in safecopy_unsafe.go
-//
-// The code is derived from Go source runtime/internal/atomic.Xchg.
-//
-//func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32)
-TEXT ·swapUint32(SB), NOSPLIT, $0-24
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleSwapUint32Fault will store a different value in this address.
-	MOVW $0, sig+20(FP)
-again:
-	MOVD addr+0(FP), R0
-	MOVW new+8(FP), R1
-	LDAXRW (R0), R2
-	STLXRW R1, (R0), R3
-	CBNZ R3, again
-	MOVW R2, old+16(FP)
-	RET
-
-// handleSwapUint64Fault returns the value stored in R1. Control is transferred
-// to it when swapUint64 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in R1.
-//
-// It must have the same frame configuration as swapUint64 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleSwapUint64Fault(SB), NOSPLIT, $0-28
-	MOVW R1, sig+24(FP)
-	RET
-
-// See the corresponding doc in safecopy_unsafe.go
-//
-// The code is derived from Go source runtime/internal/atomic.Xchg64.
-//
-//func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32)
-TEXT ·swapUint64(SB), NOSPLIT, $0-28
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleSwapUint64Fault will store a different value in this address.
-	MOVW $0, sig+24(FP)
-again:
-	MOVD addr+0(FP), R0
-	MOVD new+8(FP), R1
-	LDAXR (R0), R2
-	STLXR R1, (R0), R3
-	CBNZ R3, again
-	MOVD R2, old+16(FP)
-	RET
-
-// handleCompareAndSwapUint32Fault returns the value stored in R1. Control is
-// transferred to it when compareAndSwapUint32 below receives SIGSEGV or SIGBUS,
-// with the signal number stored in R1.
-//
-// It must have the same frame configuration as compareAndSwapUint32 so that it
-// can undo any potential call frame set up by the assembler.
-TEXT handleCompareAndSwapUint32Fault(SB), NOSPLIT, $0-24
-	MOVW R1, sig+20(FP)
-	RET
-
-// See the corresponding doc in safecopy_unsafe.go
-//
-// The code is derived from Go source runtime/internal/atomic.Cas.
-//
-//func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32)
-TEXT ·compareAndSwapUint32(SB), NOSPLIT, $0-24
-	// Store 0 as the returned signal number. If we run to completion, this is
-	// the value the caller will see; if a signal is received,
-	// handleCompareAndSwapUint32Fault will store a different value in this
-	// address.
-	MOVW $0, sig+20(FP)
-
-	MOVD addr+0(FP), R0
-	MOVW old+8(FP), R1
-	MOVW new+12(FP), R2
-again:
-	LDAXRW (R0), R3
-	CMPW R1, R3
-	BNE done
-	STLXRW R2, (R0), R4
-	CBNZ R4, again
-done:
-	MOVW R3, prev+16(FP)
-	RET
-
-// handleLoadUint32Fault returns the value stored in DI. Control is transferred
-// to it when LoadUint32 below receives SIGSEGV or SIGBUS, with the signal
-// number stored in DI.
-//
-// It must have the same frame configuration as loadUint32 so that it can undo
-// any potential call frame set up by the assembler.
-TEXT handleLoadUint32Fault(SB), NOSPLIT, $0-16
-	MOVW R1, sig+12(FP)
-	RET
-
-// loadUint32 atomically loads *addr and returns it. If a SIGSEGV or SIGBUS
-// signal is received, the value returned is unspecified, and sig is the number
-// of the signal that was received.
-//
-// Preconditions: addr must be aligned to a 4-byte boundary.
-//
-//func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32)
-TEXT ·loadUint32(SB), NOSPLIT, $0-16
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleLoadUint32Fault will store a different value in this address.
-	MOVW $0, sig+12(FP)
-
-	MOVD addr+0(FP), R0
-	LDARW (R0), R1
-	MOVW R1, val+8(FP)
-	RET
diff --git a/pkg/sentry/platform/safecopy/memclr_amd64.s b/pkg/sentry/platform/safecopy/memclr_amd64.s
deleted file mode 100644
index 64cf32f05..000000000
--- a/pkg/sentry/platform/safecopy/memclr_amd64.s
+++ /dev/null
@@ -1,147 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "textflag.h"
-
-// handleMemclrFault returns (the value stored in AX, the value stored in DI).
-// Control is transferred to it when memclr below receives SIGSEGV or SIGBUS,
-// with the faulting address stored in AX and the signal number stored in DI.
-//
-// It must have the same frame configuration as memclr so that it can undo any
-// potential call frame set up by the assembler.
-TEXT handleMemclrFault(SB), NOSPLIT, $0-28
-	MOVQ	AX, addr+16(FP)
-	MOVL	DI, sig+24(FP)
-	RET
-
-// memclr sets the n bytes following ptr to zeroes. If a SIGSEGV or SIGBUS
-// signal is received during the write, it returns the address that caused the
-// fault and the number of the signal that was received. Otherwise, it returns
-// an unspecified address and a signal number of 0.
-//
-// Data is written in order, such that if a fault happens at address p, it is
-// safe to assume that all data before p-maxRegisterSize has already been
-// successfully written.
-//
-// The code is derived from runtime.memclrNoHeapPointers.
-//
-// func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-TEXT ·memclr(SB), NOSPLIT, $0-28
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleMemclrFault will store a different value in this address.
-	MOVL	$0, sig+24(FP)
-
-	MOVQ	ptr+0(FP), DI
-	MOVQ	n+8(FP), BX
-	XORQ	AX, AX
-
-	// MOVOU seems always faster than REP STOSQ.
-tail:
-	TESTQ	BX, BX
-	JEQ	_0
-	CMPQ	BX, $2
-	JBE	_1or2
-	CMPQ	BX, $4
-	JBE	_3or4
-	CMPQ	BX, $8
-	JB	_5through7
-	JE	_8
-	CMPQ	BX, $16
-	JBE	_9through16
-	PXOR	X0, X0
-	CMPQ	BX, $32
-	JBE	_17through32
-	CMPQ	BX, $64
-	JBE	_33through64
-	CMPQ	BX, $128
-	JBE	_65through128
-	CMPQ	BX, $256
-	JBE	_129through256
-	// TODO: use branch table and BSR to make this just a single dispatch
-	// TODO: for really big clears, use MOVNTDQ, even without AVX2.
-
-loop:
-	MOVOU	X0, 0(DI)
-	MOVOU	X0, 16(DI)
-	MOVOU	X0, 32(DI)
-	MOVOU	X0, 48(DI)
-	MOVOU	X0, 64(DI)
-	MOVOU	X0, 80(DI)
-	MOVOU	X0, 96(DI)
-	MOVOU	X0, 112(DI)
-	MOVOU	X0, 128(DI)
-	MOVOU	X0, 144(DI)
-	MOVOU	X0, 160(DI)
-	MOVOU	X0, 176(DI)
-	MOVOU	X0, 192(DI)
-	MOVOU	X0, 208(DI)
-	MOVOU	X0, 224(DI)
-	MOVOU	X0, 240(DI)
-	SUBQ	$256, BX
-	ADDQ	$256, DI
-	CMPQ	BX, $256
-	JAE	loop
-	JMP	tail
-
-_1or2:
-	MOVB	AX, (DI)
-	MOVB	AX, -1(DI)(BX*1)
-	RET
-_0:
-	RET
-_3or4:
-	MOVW	AX, (DI)
-	MOVW	AX, -2(DI)(BX*1)
-	RET
-_5through7:
-	MOVL	AX, (DI)
-	MOVL	AX, -4(DI)(BX*1)
-	RET
-_8:
-	// We need a separate case for 8 to make sure we clear pointers atomically.
-	MOVQ	AX, (DI)
-	RET
-_9through16:
-	MOVQ	AX, (DI)
-	MOVQ	AX, -8(DI)(BX*1)
-	RET
-_17through32:
-	MOVOU	X0, (DI)
-	MOVOU	X0, -16(DI)(BX*1)
-	RET
-_33through64:
-	MOVOU	X0, (DI)
-	MOVOU	X0, 16(DI)
-	MOVOU	X0, -32(DI)(BX*1)
-	MOVOU	X0, -16(DI)(BX*1)
-	RET
-_65through128:
-	MOVOU	X0, (DI)
-	MOVOU	X0, 16(DI)
-	MOVOU	X0, 32(DI)
-	MOVOU	X0, 48(DI)
-	MOVOU	X0, -64(DI)(BX*1)
-	MOVOU	X0, -48(DI)(BX*1)
-	MOVOU	X0, -32(DI)(BX*1)
-	MOVOU	X0, -16(DI)(BX*1)
-	RET
-_129through256:
-	MOVOU	X0, (DI)
-	MOVOU	X0, 16(DI)
-	MOVOU	X0, 32(DI)
-	MOVOU	X0, 48(DI)
-	MOVOU	X0, 64(DI)
-	MOVOU	X0, 80(DI)
-	MOVOU	X0, 96(DI)
-	MOVOU	X0, 112(DI)
-	MOVOU	X0, -128(DI)(BX*1)
-	MOVOU	X0, -112(DI)(BX*1)
-	MOVOU	X0, -96(DI)(BX*1)
-	MOVOU	X0, -80(DI)(BX*1)
-	MOVOU	X0, -64(DI)(BX*1)
-	MOVOU	X0, -48(DI)(BX*1)
-	MOVOU	X0, -32(DI)(BX*1)
-	MOVOU	X0, -16(DI)(BX*1)
-	RET
diff --git a/pkg/sentry/platform/safecopy/memclr_arm64.s b/pkg/sentry/platform/safecopy/memclr_arm64.s
deleted file mode 100644
index 7361b9067..000000000
--- a/pkg/sentry/platform/safecopy/memclr_arm64.s
+++ /dev/null
@@ -1,74 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "textflag.h"
-
-// handleMemclrFault returns (the value stored in R0, the value stored in R1).
-// Control is transferred to it when memclr below receives SIGSEGV or SIGBUS,
-// with the faulting address stored in R0 and the signal number stored in R1.
-//
-// It must have the same frame configuration as memclr so that it can undo any
-// potential call frame set up by the assembler.
-TEXT handleMemclrFault(SB), NOSPLIT, $0-28
-	MOVD R0, addr+16(FP)
-	MOVW R1, sig+24(FP)
-	RET
-
-// See the corresponding doc in safecopy_unsafe.go
-//
-// The code is derived from runtime.memclrNoHeapPointers.
-//
-// func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-TEXT ·memclr(SB), NOSPLIT, $0-28
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleMemclrFault will store a different value in this address.
-	MOVW $0, sig+24(FP)
-	MOVD ptr+0(FP), R0
-	MOVD n+8(FP), R1
-
-	// If size is less than 16 bytes, use tail_zero to zero what remains
-	CMP $16, R1
-	BLT tail_zero
-	// Get buffer offset into 16 byte aligned address for better performance
-	ANDS $15, R0, ZR
-	BNE unaligned_to_16
-aligned_to_16:
-	LSR $4, R1, R2
-zero_by_16:
-	STP.P (ZR, ZR), 16(R0) // Store pair with post index.
-	SUBS $1, R2, R2
-	BNE zero_by_16
-	ANDS $15, R1, R1
-	BEQ end
-
-	// Zero buffer with size=R1 < 16
-tail_zero:
-	TBZ $3, R1, tail_zero_4
-	MOVD.P ZR, 8(R0)
-tail_zero_4:
-	TBZ $2, R1, tail_zero_2
-	MOVW.P ZR, 4(R0)
-tail_zero_2:
-	TBZ $1, R1, tail_zero_1
-	MOVH.P ZR, 2(R0)
-tail_zero_1:
-	TBZ $0, R1, end
-	MOVB ZR, (R0)
-end:
-	RET
-
-unaligned_to_16:
-	MOVD R0, R2
-head_loop:
-	MOVBU.P ZR, 1(R0)
-	ANDS $15, R0, ZR
-	BNE head_loop
-	// Adjust length for what remains
-	SUB R2, R0, R3
-	SUB R3, R1
-	// If size is less than 16 bytes, use tail_zero to zero what remains
-	CMP $16, R1
-	BLT tail_zero
-	B aligned_to_16
diff --git a/pkg/sentry/platform/safecopy/memcpy_amd64.s b/pkg/sentry/platform/safecopy/memcpy_amd64.s
deleted file mode 100644
index 129691d68..000000000
--- a/pkg/sentry/platform/safecopy/memcpy_amd64.s
+++ /dev/null
@@ -1,250 +0,0 @@
-// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved.
-// Revisions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com).  All rights reserved.
-// Portions Copyright 2009 The Go Authors. All rights reserved.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy
-// of this software and associated documentation files (the "Software"), to deal
-// in the Software without restriction, including without limitation the rights
-// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-// copies of the Software, and to permit persons to whom the Software is
-// furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in
-// all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
-// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-// THE SOFTWARE.
-
-#include "textflag.h"
-
-// handleMemcpyFault returns (the value stored in AX, the value stored in DI).
-// Control is transferred to it when memcpy below receives SIGSEGV or SIGBUS,
-// with the faulting address stored in AX and the signal number stored in DI.
-//
-// It must have the same frame configuration as memcpy so that it can undo any
-// potential call frame set up by the assembler.
-TEXT handleMemcpyFault(SB), NOSPLIT, $0-36
-	MOVQ	AX, addr+24(FP)
-	MOVL	DI, sig+32(FP)
-	RET
-
-// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received
-// during the copy, it returns the address that caused the fault and the number
-// of the signal that was received. Otherwise, it returns an unspecified address
-// and a signal number of 0.
-//
-// Data is copied in order, such that if a fault happens at address p, it is
-// safe to assume that all data before p-maxRegisterSize has already been
-// successfully copied.
-//
-// The code is derived from the forward copying part of runtime.memmove.
-//
-// func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-TEXT ·memcpy(SB), NOSPLIT, $0-36
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleMemcpyFault will store a different value in this address.
-	MOVL	$0, sig+32(FP)
-
-	MOVQ	to+0(FP), DI
-	MOVQ	from+8(FP), SI
-	MOVQ	n+16(FP), BX
-
-	// REP instructions have a high startup cost, so we handle small sizes
-	// with some straightline code. The REP MOVSQ instruction is really fast
-	// for large sizes. The cutover is approximately 2K.
-tail:
-	// move_129through256 or smaller work whether or not the source and the
-	// destination memory regions overlap because they load all data into
-	// registers before writing it back.  move_256through2048 on the other
-	// hand can be used only when the memory regions don't overlap or the copy
-	// direction is forward.
-	TESTQ	BX, BX
-	JEQ	move_0
-	CMPQ	BX, $2
-	JBE	move_1or2
-	CMPQ	BX, $4
-	JBE	move_3or4
-	CMPQ	BX, $8
-	JB	move_5through7
-	JE	move_8
-	CMPQ	BX, $16
-	JBE	move_9through16
-	CMPQ	BX, $32
-	JBE	move_17through32
-	CMPQ	BX, $64
-	JBE	move_33through64
-	CMPQ	BX, $128
-	JBE	move_65through128
-	CMPQ	BX, $256
-	JBE	move_129through256
-	// TODO: use branch table and BSR to make this just a single dispatch
-
-/*
- * forward copy loop
- */
-	CMPQ	BX, $2048
-	JLS	move_256through2048
-
-	// Check alignment
-	MOVL	SI, AX
-	ORL	DI, AX
-	TESTL	$7, AX
-	JEQ	fwdBy8
-
-	// Do 1 byte at a time
-	MOVQ	BX, CX
-	REP;	MOVSB
-	RET
-
-fwdBy8:
-	// Do 8 bytes at a time
-	MOVQ	BX, CX
-	SHRQ	$3, CX
-	ANDQ	$7, BX
-	REP;	MOVSQ
-	JMP	tail
-
-move_1or2:
-	MOVB	(SI), AX
-	MOVB	AX, (DI)
-	MOVB	-1(SI)(BX*1), CX
-	MOVB	CX, -1(DI)(BX*1)
-	RET
-move_0:
-	RET
-move_3or4:
-	MOVW	(SI), AX
-	MOVW	AX, (DI)
-	MOVW	-2(SI)(BX*1), CX
-	MOVW	CX, -2(DI)(BX*1)
-	RET
-move_5through7:
-	MOVL	(SI), AX
-	MOVL	AX, (DI)
-	MOVL	-4(SI)(BX*1), CX
-	MOVL	CX, -4(DI)(BX*1)
-	RET
-move_8:
-	// We need a separate case for 8 to make sure we write pointers atomically.
-	MOVQ	(SI), AX
-	MOVQ	AX, (DI)
-	RET
-move_9through16:
-	MOVQ	(SI), AX
-	MOVQ	AX, (DI)
-	MOVQ	-8(SI)(BX*1), CX
-	MOVQ	CX, -8(DI)(BX*1)
-	RET
-move_17through32:
-	MOVOU	(SI), X0
-	MOVOU	X0, (DI)
-	MOVOU	-16(SI)(BX*1), X1
-	MOVOU	X1, -16(DI)(BX*1)
-	RET
-move_33through64:
-	MOVOU	(SI), X0
-	MOVOU	X0, (DI)
-	MOVOU	16(SI), X1
-	MOVOU	X1, 16(DI)
-	MOVOU	-32(SI)(BX*1), X2
-	MOVOU	X2, -32(DI)(BX*1)
-	MOVOU	-16(SI)(BX*1), X3
-	MOVOU	X3, -16(DI)(BX*1)
-	RET
-move_65through128:
-	MOVOU	(SI), X0
-	MOVOU	X0, (DI)
-	MOVOU	16(SI), X1
-	MOVOU	X1, 16(DI)
-	MOVOU	32(SI), X2
-	MOVOU	X2, 32(DI)
-	MOVOU	48(SI), X3
-	MOVOU	X3, 48(DI)
-	MOVOU	-64(SI)(BX*1), X4
-	MOVOU	X4, -64(DI)(BX*1)
-	MOVOU	-48(SI)(BX*1), X5
-	MOVOU	X5, -48(DI)(BX*1)
-	MOVOU	-32(SI)(BX*1), X6
-	MOVOU	X6, -32(DI)(BX*1)
-	MOVOU	-16(SI)(BX*1), X7
-	MOVOU	X7, -16(DI)(BX*1)
-	RET
-move_129through256:
-	MOVOU	(SI), X0
-	MOVOU	X0, (DI)
-	MOVOU	16(SI), X1
-	MOVOU	X1, 16(DI)
-	MOVOU	32(SI), X2
-	MOVOU	X2, 32(DI)
-	MOVOU	48(SI), X3
-	MOVOU	X3, 48(DI)
-	MOVOU	64(SI), X4
-	MOVOU	X4, 64(DI)
-	MOVOU	80(SI), X5
-	MOVOU	X5, 80(DI)
-	MOVOU	96(SI), X6
-	MOVOU	X6, 96(DI)
-	MOVOU	112(SI), X7
-	MOVOU	X7, 112(DI)
-	MOVOU	-128(SI)(BX*1), X8
-	MOVOU	X8, -128(DI)(BX*1)
-	MOVOU	-112(SI)(BX*1), X9
-	MOVOU	X9, -112(DI)(BX*1)
-	MOVOU	-96(SI)(BX*1), X10
-	MOVOU	X10, -96(DI)(BX*1)
-	MOVOU	-80(SI)(BX*1), X11
-	MOVOU	X11, -80(DI)(BX*1)
-	MOVOU	-64(SI)(BX*1), X12
-	MOVOU	X12, -64(DI)(BX*1)
-	MOVOU	-48(SI)(BX*1), X13
-	MOVOU	X13, -48(DI)(BX*1)
-	MOVOU	-32(SI)(BX*1), X14
-	MOVOU	X14, -32(DI)(BX*1)
-	MOVOU	-16(SI)(BX*1), X15
-	MOVOU	X15, -16(DI)(BX*1)
-	RET
-move_256through2048:
-	SUBQ	$256, BX
-	MOVOU	(SI), X0
-	MOVOU	X0, (DI)
-	MOVOU	16(SI), X1
-	MOVOU	X1, 16(DI)
-	MOVOU	32(SI), X2
-	MOVOU	X2, 32(DI)
-	MOVOU	48(SI), X3
-	MOVOU	X3, 48(DI)
-	MOVOU	64(SI), X4
-	MOVOU	X4, 64(DI)
-	MOVOU	80(SI), X5
-	MOVOU	X5, 80(DI)
-	MOVOU	96(SI), X6
-	MOVOU	X6, 96(DI)
-	MOVOU	112(SI), X7
-	MOVOU	X7, 112(DI)
-	MOVOU	128(SI), X8
-	MOVOU	X8, 128(DI)
-	MOVOU	144(SI), X9
-	MOVOU	X9, 144(DI)
-	MOVOU	160(SI), X10
-	MOVOU	X10, 160(DI)
-	MOVOU	176(SI), X11
-	MOVOU	X11, 176(DI)
-	MOVOU	192(SI), X12
-	MOVOU	X12, 192(DI)
-	MOVOU	208(SI), X13
-	MOVOU	X13, 208(DI)
-	MOVOU	224(SI), X14
-	MOVOU	X14, 224(DI)
-	MOVOU	240(SI), X15
-	MOVOU	X15, 240(DI)
-	CMPQ	BX, $256
-	LEAQ	256(SI), SI
-	LEAQ	256(DI), DI
-	JGE	move_256through2048
-	JMP	tail
diff --git a/pkg/sentry/platform/safecopy/memcpy_arm64.s b/pkg/sentry/platform/safecopy/memcpy_arm64.s
deleted file mode 100644
index e7e541565..000000000
--- a/pkg/sentry/platform/safecopy/memcpy_arm64.s
+++ /dev/null
@@ -1,78 +0,0 @@
-// Copyright 2014 The Go Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style
-// license that can be found in the LICENSE file.
-
-#include "textflag.h"
-
-// handleMemcpyFault returns (the value stored in R0, the value stored in R1).
-// Control is transferred to it when memcpy below receives SIGSEGV or SIGBUS,
-// with the faulting address stored in R0 and the signal number stored in R1.
-//
-// It must have the same frame configuration as memcpy so that it can undo any
-// potential call frame set up by the assembler.
-TEXT handleMemcpyFault(SB), NOSPLIT, $0-36
-	MOVD R0, addr+24(FP)
-	MOVW R1, sig+32(FP)
-	RET
-
-// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received
-// during the copy, it returns the address that caused the fault and the number
-// of the signal that was received. Otherwise, it returns an unspecified address
-// and a signal number of 0.
-//
-// Data is copied in order, such that if a fault happens at address p, it is
-// safe to assume that all data before p-maxRegisterSize has already been
-// successfully copied.
-//
-// The code is derived from the Go source runtime.memmove.
-//
-// func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-TEXT ·memcpy(SB), NOSPLIT, $-8-36
-	// Store 0 as the returned signal number. If we run to completion,
-	// this is the value the caller will see; if a signal is received,
-	// handleMemcpyFault will store a different value in this address.
-	MOVW $0, sig+32(FP)
-
-	MOVD to+0(FP), R3
-	MOVD from+8(FP), R4
-	MOVD n+16(FP), R5
-	CMP $0, R5
-	BNE check
-	RET
-
-check:
-	AND $~7, R5, R7     // R7 is N&~7.
-	SUB R7, R5, R6      // R6 is N&7.
-
-	// Copying forward proceeds by copying R7/8 words then copying R6 bytes.
-	// R3 and R4 are advanced as we copy.
-
-	// (There may be implementations of armv8 where copying by bytes until
-	// at least one of source or dest is word aligned is a worthwhile
-	// optimization, but the on the one tested so far (xgene) it did not
-	// make a significance difference.)
-
-	CMP $0, R7          // Do we need to do any word-by-word copying?
-	BEQ noforwardlarge
-	ADD R3, R7, R9      // R9 points just past where we copy by word.
-
-forwardlargeloop:
-	MOVD.P 8(R4), R8       // R8 is just a scratch register.
-	MOVD.P R8, 8(R3)
-	CMP R3, R9
-	BNE forwardlargeloop
-
-noforwardlarge:
-	CMP $0, R6          // Do we need to do any byte-by-byte copying?
-	BNE forwardtail
-	RET
-
-forwardtail:
-	ADD R3, R6, R9      // R9 points just past the destination memory.
-
-forwardtailloop:
-	MOVBU.P 1(R4), R8
-	MOVBU.P R8, 1(R3)
-	CMP R3, R9
-	BNE forwardtailloop
-	RET
diff --git a/pkg/sentry/platform/safecopy/safecopy.go b/pkg/sentry/platform/safecopy/safecopy.go
deleted file mode 100644
index 2fb7e5809..000000000
--- a/pkg/sentry/platform/safecopy/safecopy.go
+++ /dev/null
@@ -1,144 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-// Package safecopy provides an efficient implementation of functions to access
-// memory that may result in SIGSEGV or SIGBUS being sent to the accessor.
-package safecopy
-
-import (
-	"fmt"
-	"reflect"
-	"runtime"
-	"syscall"
-
-	"gvisor.dev/gvisor/pkg/syserror"
-)
-
-// SegvError is returned when a safecopy function receives SIGSEGV.
-type SegvError struct {
-	// Addr is the address at which the SIGSEGV occurred.
-	Addr uintptr
-}
-
-// Error implements error.Error.
-func (e SegvError) Error() string {
-	return fmt.Sprintf("SIGSEGV at %#x", e.Addr)
-}
-
-// BusError is returned when a safecopy function receives SIGBUS.
-type BusError struct {
-	// Addr is the address at which the SIGBUS occurred.
-	Addr uintptr
-}
-
-// Error implements error.Error.
-func (e BusError) Error() string {
-	return fmt.Sprintf("SIGBUS at %#x", e.Addr)
-}
-
-// AlignmentError is returned when a safecopy function is passed an address
-// that does not meet alignment requirements.
-type AlignmentError struct {
-	// Addr is the invalid address.
-	Addr uintptr
-
-	// Alignment is the required alignment.
-	Alignment uintptr
-}
-
-// Error implements error.Error.
-func (e AlignmentError) Error() string {
-	return fmt.Sprintf("address %#x is not aligned to a %d-byte boundary", e.Addr, e.Alignment)
-}
-
-var (
-	// The begin and end addresses below are for the functions that are
-	// checked by the signal handler.
-	memcpyBegin               uintptr
-	memcpyEnd                 uintptr
-	memclrBegin               uintptr
-	memclrEnd                 uintptr
-	swapUint32Begin           uintptr
-	swapUint32End             uintptr
-	swapUint64Begin           uintptr
-	swapUint64End             uintptr
-	compareAndSwapUint32Begin uintptr
-	compareAndSwapUint32End   uintptr
-	loadUint32Begin           uintptr
-	loadUint32End             uintptr
-
-	// savedSigSegVHandler is a pointer to the SIGSEGV handler that was
-	// configured before we replaced it with our own. We still call into it
-	// when we get a SIGSEGV that is not interesting to us.
-	savedSigSegVHandler uintptr
-
-	// same a above, but for SIGBUS signals.
-	savedSigBusHandler uintptr
-)
-
-// signalHandler is our replacement signal handler for SIGSEGV and SIGBUS
-// signals.
-func signalHandler()
-
-// FindEndAddress returns the end address (one byte beyond the last) of the
-// function that contains the specified address (begin).
-func FindEndAddress(begin uintptr) uintptr {
-	f := runtime.FuncForPC(begin)
-	if f != nil {
-		for p := begin; ; p++ {
-			g := runtime.FuncForPC(p)
-			if f != g {
-				return p
-			}
-		}
-	}
-	return begin
-}
-
-// initializeAddresses initializes the addresses used by the signal handler.
-func initializeAddresses() {
-	// The following functions are written in assembly language, so they won't
-	// be inlined by the existing compiler/linker. Tests will fail if this
-	// assumption is violated.
-	memcpyBegin = reflect.ValueOf(memcpy).Pointer()
-	memcpyEnd = FindEndAddress(memcpyBegin)
-	memclrBegin = reflect.ValueOf(memclr).Pointer()
-	memclrEnd = FindEndAddress(memclrBegin)
-	swapUint32Begin = reflect.ValueOf(swapUint32).Pointer()
-	swapUint32End = FindEndAddress(swapUint32Begin)
-	swapUint64Begin = reflect.ValueOf(swapUint64).Pointer()
-	swapUint64End = FindEndAddress(swapUint64Begin)
-	compareAndSwapUint32Begin = reflect.ValueOf(compareAndSwapUint32).Pointer()
-	compareAndSwapUint32End = FindEndAddress(compareAndSwapUint32Begin)
-	loadUint32Begin = reflect.ValueOf(loadUint32).Pointer()
-	loadUint32End = FindEndAddress(loadUint32Begin)
-}
-
-func init() {
-	initializeAddresses()
-	if err := ReplaceSignalHandler(syscall.SIGSEGV, reflect.ValueOf(signalHandler).Pointer(), &savedSigSegVHandler); err != nil {
-		panic(fmt.Sprintf("Unable to set handler for SIGSEGV: %v", err))
-	}
-	if err := ReplaceSignalHandler(syscall.SIGBUS, reflect.ValueOf(signalHandler).Pointer(), &savedSigBusHandler); err != nil {
-		panic(fmt.Sprintf("Unable to set handler for SIGBUS: %v", err))
-	}
-	syserror.AddErrorUnwrapper(func(e error) (syscall.Errno, bool) {
-		switch e.(type) {
-		case SegvError, BusError, AlignmentError:
-			return syscall.EFAULT, true
-		default:
-			return 0, false
-		}
-	})
-}
diff --git a/pkg/sentry/platform/safecopy/safecopy_test.go b/pkg/sentry/platform/safecopy/safecopy_test.go
deleted file mode 100644
index 5818f7f9b..000000000
--- a/pkg/sentry/platform/safecopy/safecopy_test.go
+++ /dev/null
@@ -1,617 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package safecopy
-
-import (
-	"bytes"
-	"fmt"
-	"io/ioutil"
-	"math/rand"
-	"os"
-	"runtime/debug"
-	"syscall"
-	"testing"
-	"unsafe"
-)
-
-// Size of a page in bytes. Cloned from usermem.PageSize to avoid a circular
-// dependency.
-const pageSize = 4096
-
-func initRandom(b []byte) {
-	for i := range b {
-		b[i] = byte(rand.Intn(256))
-	}
-}
-
-func randBuf(size int) []byte {
-	b := make([]byte, size)
-	initRandom(b)
-	return b
-}
-
-func TestCopyInSuccess(t *testing.T) {
-	// Test that CopyIn does not return an error when all pages are accessible.
-	const bufLen = 8192
-	a := randBuf(bufLen)
-	b := make([]byte, bufLen)
-
-	n, err := CopyIn(b, unsafe.Pointer(&a[0]))
-	if n != bufLen {
-		t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen)
-	}
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if !bytes.Equal(a, b) {
-		t.Errorf("Buffers are not equal when they should be: %v %v", a, b)
-	}
-}
-
-func TestCopyOutSuccess(t *testing.T) {
-	// Test that CopyOut does not return an error when all pages are
-	// accessible.
-	const bufLen = 8192
-	a := randBuf(bufLen)
-	b := make([]byte, bufLen)
-
-	n, err := CopyOut(unsafe.Pointer(&b[0]), a)
-	if n != bufLen {
-		t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen)
-	}
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if !bytes.Equal(a, b) {
-		t.Errorf("Buffers are not equal when they should be: %v %v", a, b)
-	}
-}
-
-func TestCopySuccess(t *testing.T) {
-	// Test that Copy does not return an error when all pages are accessible.
-	const bufLen = 8192
-	a := randBuf(bufLen)
-	b := make([]byte, bufLen)
-
-	n, err := Copy(unsafe.Pointer(&b[0]), unsafe.Pointer(&a[0]), bufLen)
-	if n != bufLen {
-		t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen)
-	}
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if !bytes.Equal(a, b) {
-		t.Errorf("Buffers are not equal when they should be: %v %v", a, b)
-	}
-}
-
-func TestZeroOutSuccess(t *testing.T) {
-	// Test that ZeroOut does not return an error when all pages are
-	// accessible.
-	const bufLen = 8192
-	a := make([]byte, bufLen)
-	b := randBuf(bufLen)
-
-	n, err := ZeroOut(unsafe.Pointer(&b[0]), bufLen)
-	if n != bufLen {
-		t.Errorf("Unexpected copy length, got %v, want %v", n, bufLen)
-	}
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if !bytes.Equal(a, b) {
-		t.Errorf("Buffers are not equal when they should be: %v %v", a, b)
-	}
-}
-
-func TestSwapUint32Success(t *testing.T) {
-	// Test that SwapUint32 does not return an error when the page is
-	// accessible.
-	before := uint32(rand.Int31())
-	after := uint32(rand.Int31())
-	val := before
-
-	old, err := SwapUint32(unsafe.Pointer(&val), after)
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if old != before {
-		t.Errorf("Unexpected old value: got %v, want %v", old, before)
-	}
-	if val != after {
-		t.Errorf("Unexpected new value: got %v, want %v", val, after)
-	}
-}
-
-func TestSwapUint32AlignmentError(t *testing.T) {
-	// Test that SwapUint32 returns an AlignmentError when passed an unaligned
-	// address.
-	data := new(struct{ val uint64 })
-	addr := uintptr(unsafe.Pointer(&data.val)) + 1
-	want := AlignmentError{Addr: addr, Alignment: 4}
-	if _, err := SwapUint32(unsafe.Pointer(addr), 1); err != want {
-		t.Errorf("Unexpected error: got %v, want %v", err, want)
-	}
-}
-
-func TestSwapUint64Success(t *testing.T) {
-	// Test that SwapUint64 does not return an error when the page is
-	// accessible.
-	before := uint64(rand.Int63())
-	after := uint64(rand.Int63())
-	// "The first word in ... an allocated struct or slice can be relied upon
-	// to be 64-bit aligned." - sync/atomic docs
-	data := new(struct{ val uint64 })
-	data.val = before
-
-	old, err := SwapUint64(unsafe.Pointer(&data.val), after)
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if old != before {
-		t.Errorf("Unexpected old value: got %v, want %v", old, before)
-	}
-	if data.val != after {
-		t.Errorf("Unexpected new value: got %v, want %v", data.val, after)
-	}
-}
-
-func TestSwapUint64AlignmentError(t *testing.T) {
-	// Test that SwapUint64 returns an AlignmentError when passed an unaligned
-	// address.
-	data := new(struct{ val1, val2 uint64 })
-	addr := uintptr(unsafe.Pointer(&data.val1)) + 1
-	want := AlignmentError{Addr: addr, Alignment: 8}
-	if _, err := SwapUint64(unsafe.Pointer(addr), 1); err != want {
-		t.Errorf("Unexpected error: got %v, want %v", err, want)
-	}
-}
-
-func TestCompareAndSwapUint32Success(t *testing.T) {
-	// Test that CompareAndSwapUint32 does not return an error when the page is
-	// accessible.
-	before := uint32(rand.Int31())
-	after := uint32(rand.Int31())
-	val := before
-
-	old, err := CompareAndSwapUint32(unsafe.Pointer(&val), before, after)
-	if err != nil {
-		t.Errorf("Unexpected error: %v", err)
-	}
-	if old != before {
-		t.Errorf("Unexpected old value: got %v, want %v", old, before)
-	}
-	if val != after {
-		t.Errorf("Unexpected new value: got %v, want %v", val, after)
-	}
-}
-
-func TestCompareAndSwapUint32AlignmentError(t *testing.T) {
-	// Test that CompareAndSwapUint32 returns an AlignmentError when passed an
-	// unaligned address.
-	data := new(struct{ val uint64 })
-	addr := uintptr(unsafe.Pointer(&data.val)) + 1
-	want := AlignmentError{Addr: addr, Alignment: 4}
-	if _, err := CompareAndSwapUint32(unsafe.Pointer(addr), 0, 1); err != want {
-		t.Errorf("Unexpected error: got %v, want %v", err, want)
-	}
-}
-
-// withSegvErrorTestMapping calls fn with a two-page mapping. The first page
-// contains random data, and the second page generates SIGSEGV when accessed.
-func withSegvErrorTestMapping(t *testing.T, fn func(m []byte)) {
-	mapping, err := syscall.Mmap(-1, 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_ANONYMOUS|syscall.MAP_PRIVATE)
-	if err != nil {
-		t.Fatalf("Mmap failed: %v", err)
-	}
-	defer syscall.Munmap(mapping)
-	if err := syscall.Mprotect(mapping[pageSize:], syscall.PROT_NONE); err != nil {
-		t.Fatalf("Mprotect failed: %v", err)
-	}
-	initRandom(mapping[:pageSize])
-
-	fn(mapping)
-}
-
-// withBusErrorTestMapping calls fn with a two-page mapping. The first page
-// contains random data, and the second page generates SIGBUS when accessed.
-func withBusErrorTestMapping(t *testing.T, fn func(m []byte)) {
-	f, err := ioutil.TempFile("", "sigbus_test")
-	if err != nil {
-		t.Fatalf("TempFile failed: %v", err)
-	}
-	defer f.Close()
-	if err := f.Truncate(pageSize); err != nil {
-		t.Fatalf("Truncate failed: %v", err)
-	}
-	mapping, err := syscall.Mmap(int(f.Fd()), 0, 2*pageSize, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
-	if err != nil {
-		t.Fatalf("Mmap failed: %v", err)
-	}
-	defer syscall.Munmap(mapping)
-	initRandom(mapping[:pageSize])
-
-	fn(mapping)
-}
-
-func TestCopyInSegvError(t *testing.T) {
-	// Test that CopyIn returns a SegvError when reaching a page that signals
-	// SIGSEGV.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withSegvErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				dst := randBuf(pageSize)
-				n, err := CopyIn(dst, src)
-				if n != bytesBeforeFault {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (SegvError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopyInBusError(t *testing.T) {
-	// Test that CopyIn returns a BusError when reaching a page that signals
-	// SIGBUS.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) {
-			withBusErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				dst := randBuf(pageSize)
-				n, err := CopyIn(dst, src)
-				if n != bytesBeforeFault {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (BusError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopyOutSegvError(t *testing.T) {
-	// Test that CopyOut returns a SegvError when reaching a page that signals
-	// SIGSEGV.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withSegvErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				src := randBuf(pageSize)
-				n, err := CopyOut(dst, src)
-				if n != bytesBeforeFault {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (SegvError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopyOutBusError(t *testing.T) {
-	// Test that CopyOut returns a BusError when reaching a page that signals
-	// SIGBUS.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withBusErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				src := randBuf(pageSize)
-				n, err := CopyOut(dst, src)
-				if n != bytesBeforeFault {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (BusError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopySourceSegvError(t *testing.T) {
-	// Test that Copy returns a SegvError when copying from a page that signals
-	// SIGSEGV.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withSegvErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				dst := randBuf(pageSize)
-				n, err := Copy(unsafe.Pointer(&dst[0]), src, pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (SegvError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopySourceBusError(t *testing.T) {
-	// Test that Copy returns a BusError when copying from a page that signals
-	// SIGBUS.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) {
-			withBusErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				src := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				dst := randBuf(pageSize)
-				n, err := Copy(unsafe.Pointer(&dst[0]), src, pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (BusError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := dst[:bytesBeforeFault], mapping[pageSize-bytesBeforeFault:pageSize]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopyDestinationSegvError(t *testing.T) {
-	// Test that Copy returns a SegvError when copying to a page that signals
-	// SIGSEGV.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withSegvErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				src := randBuf(pageSize)
-				n, err := Copy(dst, unsafe.Pointer(&src[0]), pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (SegvError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestCopyDestinationBusError(t *testing.T) {
-	// Test that Copy returns a BusError when copying to a page that signals
-	// SIGBUS.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting copy %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) {
-			withBusErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				src := randBuf(pageSize)
-				n, err := Copy(dst, unsafe.Pointer(&src[0]), pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected copy length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (BusError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], src[:bytesBeforeFault]; !bytes.Equal(got, want) {
-					t.Errorf("Buffers are not equal when they should be: %v %v", got, want)
-				}
-			})
-		})
-	}
-}
-
-func TestZeroOutSegvError(t *testing.T) {
-	// Test that ZeroOut returns a SegvError when reaching a page that signals
-	// SIGSEGV.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting write %d bytes before SIGSEGV", bytesBeforeFault), func(t *testing.T) {
-			withSegvErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				n, err := ZeroOut(dst, pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected write length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (SegvError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], make([]byte, bytesBeforeFault); !bytes.Equal(got, want) {
-					t.Errorf("Non-zero bytes in written part of mapping: %v", got)
-				}
-			})
-		})
-	}
-}
-
-func TestZeroOutBusError(t *testing.T) {
-	// Test that ZeroOut returns a BusError when reaching a page that signals
-	// SIGBUS.
-	for bytesBeforeFault := 0; bytesBeforeFault <= 2*maxRegisterSize; bytesBeforeFault++ {
-		t.Run(fmt.Sprintf("starting write %d bytes before SIGBUS", bytesBeforeFault), func(t *testing.T) {
-			withBusErrorTestMapping(t, func(mapping []byte) {
-				secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-				dst := unsafe.Pointer(secondPage - uintptr(bytesBeforeFault))
-				n, err := ZeroOut(dst, pageSize)
-				if n != uintptr(bytesBeforeFault) {
-					t.Errorf("Unexpected write length: got %v, want %v", n, bytesBeforeFault)
-				}
-				if want := (BusError{secondPage}); err != want {
-					t.Errorf("Unexpected error: got %v, want %v", err, want)
-				}
-				if got, want := mapping[pageSize-bytesBeforeFault:pageSize], make([]byte, bytesBeforeFault); !bytes.Equal(got, want) {
-					t.Errorf("Non-zero bytes in written part of mapping: %v", got)
-				}
-			})
-		})
-	}
-}
-
-func TestSwapUint32SegvError(t *testing.T) {
-	// Test that SwapUint32 returns a SegvError when reaching a page that
-	// signals SIGSEGV.
-	withSegvErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := SwapUint32(unsafe.Pointer(secondPage), 1)
-		if want := (SegvError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func TestSwapUint32BusError(t *testing.T) {
-	// Test that SwapUint32 returns a BusError when reaching a page that
-	// signals SIGBUS.
-	withBusErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := SwapUint32(unsafe.Pointer(secondPage), 1)
-		if want := (BusError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func TestSwapUint64SegvError(t *testing.T) {
-	// Test that SwapUint64 returns a SegvError when reaching a page that
-	// signals SIGSEGV.
-	withSegvErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := SwapUint64(unsafe.Pointer(secondPage), 1)
-		if want := (SegvError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func TestSwapUint64BusError(t *testing.T) {
-	// Test that SwapUint64 returns a BusError when reaching a page that
-	// signals SIGBUS.
-	withBusErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := SwapUint64(unsafe.Pointer(secondPage), 1)
-		if want := (BusError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func TestCompareAndSwapUint32SegvError(t *testing.T) {
-	// Test that CompareAndSwapUint32 returns a SegvError when reaching a page
-	// that signals SIGSEGV.
-	withSegvErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := CompareAndSwapUint32(unsafe.Pointer(secondPage), 0, 1)
-		if want := (SegvError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func TestCompareAndSwapUint32BusError(t *testing.T) {
-	// Test that CompareAndSwapUint32 returns a BusError when reaching a page
-	// that signals SIGBUS.
-	withBusErrorTestMapping(t, func(mapping []byte) {
-		secondPage := uintptr(unsafe.Pointer(&mapping[0])) + pageSize
-		_, err := CompareAndSwapUint32(unsafe.Pointer(secondPage), 0, 1)
-		if want := (BusError{secondPage}); err != want {
-			t.Errorf("Unexpected error: got %v, want %v", err, want)
-		}
-	})
-}
-
-func testCopy(dst, src []byte) (panicked bool) {
-	defer func() {
-		if r := recover(); r != nil {
-			panicked = true
-		}
-	}()
-	debug.SetPanicOnFault(true)
-	copy(dst, src)
-	return
-}
-
-func TestSegVOnMemmove(t *testing.T) {
-	// Test that SIGSEGVs received by runtime.memmove when *not* doing
-	// CopyIn or CopyOut work gets propagated to the runtime.
-	const bufLen = pageSize
-	a, err := syscall.Mmap(-1, 0, bufLen, syscall.PROT_NONE, syscall.MAP_ANON|syscall.MAP_PRIVATE)
-	if err != nil {
-		t.Fatalf("Mmap failed: %v", err)
-
-	}
-	defer syscall.Munmap(a)
-	b := randBuf(bufLen)
-
-	if !testCopy(b, a) {
-		t.Fatalf("testCopy didn't panic when it should have")
-	}
-
-	if !testCopy(a, b) {
-		t.Fatalf("testCopy didn't panic when it should have")
-	}
-}
-
-func TestSigbusOnMemmove(t *testing.T) {
-	// Test that SIGBUS received by runtime.memmove when *not* doing
-	// CopyIn or CopyOut work gets propagated to the runtime.
-	const bufLen = pageSize
-	f, err := ioutil.TempFile("", "sigbus_test")
-	if err != nil {
-		t.Fatalf("TempFile failed: %v", err)
-	}
-	os.Remove(f.Name())
-	defer f.Close()
-
-	a, err := syscall.Mmap(int(f.Fd()), 0, bufLen, syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED)
-	if err != nil {
-		t.Fatalf("Mmap failed: %v", err)
-
-	}
-	defer syscall.Munmap(a)
-	b := randBuf(bufLen)
-
-	if !testCopy(b, a) {
-		t.Fatalf("testCopy didn't panic when it should have")
-	}
-
-	if !testCopy(a, b) {
-		t.Fatalf("testCopy didn't panic when it should have")
-	}
-}
diff --git a/pkg/sentry/platform/safecopy/safecopy_unsafe.go b/pkg/sentry/platform/safecopy/safecopy_unsafe.go
deleted file mode 100644
index eef028e68..000000000
--- a/pkg/sentry/platform/safecopy/safecopy_unsafe.go
+++ /dev/null
@@ -1,335 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-package safecopy
-
-import (
-	"fmt"
-	"syscall"
-	"unsafe"
-)
-
-// maxRegisterSize is the maximum register size used in memcpy and memclr. It
-// is used to decide by how much to rewind the copy (for memcpy) or zeroing
-// (for memclr) before proceeding.
-const maxRegisterSize = 16
-
-// memcpy copies data from src to dst. If a SIGSEGV or SIGBUS signal is received
-// during the copy, it returns the address that caused the fault and the number
-// of the signal that was received. Otherwise, it returns an unspecified address
-// and a signal number of 0.
-//
-// Data is copied in order, such that if a fault happens at address p, it is
-// safe to assume that all data before p-maxRegisterSize has already been
-// successfully copied.
-//
-//go:noescape
-func memcpy(dst, src unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-
-// memclr sets the n bytes following ptr to zeroes. If a SIGSEGV or SIGBUS
-// signal is received during the write, it returns the address that caused the
-// fault and the number of the signal that was received. Otherwise, it returns
-// an unspecified address and a signal number of 0.
-//
-// Data is written in order, such that if a fault happens at address p, it is
-// safe to assume that all data before p-maxRegisterSize has already been
-// successfully written.
-//
-//go:noescape
-func memclr(ptr unsafe.Pointer, n uintptr) (fault unsafe.Pointer, sig int32)
-
-// swapUint32 atomically stores new into *ptr and returns (the previous *ptr
-// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the
-// value of old is unspecified, and sig is the number of the signal that was
-// received.
-//
-// Preconditions: ptr must be aligned to a 4-byte boundary.
-//
-//go:noescape
-func swapUint32(ptr unsafe.Pointer, new uint32) (old uint32, sig int32)
-
-// swapUint64 atomically stores new into *ptr and returns (the previous *ptr
-// value, 0). If a SIGSEGV or SIGBUS signal is received during the swap, the
-// value of old is unspecified, and sig is the number of the signal that was
-// received.
-//
-// Preconditions: ptr must be aligned to a 8-byte boundary.
-//
-//go:noescape
-func swapUint64(ptr unsafe.Pointer, new uint64) (old uint64, sig int32)
-
-// compareAndSwapUint32 is like sync/atomic.CompareAndSwapUint32, but returns
-// (the value previously stored at ptr, 0). If a SIGSEGV or SIGBUS signal is
-// received during the operation, the value of prev is unspecified, and sig is
-// the number of the signal that was received.
-//
-// Preconditions: ptr must be aligned to a 4-byte boundary.
-//
-//go:noescape
-func compareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (prev uint32, sig int32)
-
-// LoadUint32 is like sync/atomic.LoadUint32, but operates with user memory. It
-// may fail with SIGSEGV or SIGBUS if it is received while reading from ptr.
-//
-// Preconditions: ptr must be aligned to a 4-byte boundary.
-//
-//go:noescape
-func loadUint32(ptr unsafe.Pointer) (val uint32, sig int32)
-
-// CopyIn copies len(dst) bytes from src to dst. It returns the number of bytes
-// copied and an error if SIGSEGV or SIGBUS is received while reading from src.
-func CopyIn(dst []byte, src unsafe.Pointer) (int, error) {
-	toCopy := uintptr(len(dst))
-	if len(dst) == 0 {
-		return 0, nil
-	}
-
-	fault, sig := memcpy(unsafe.Pointer(&dst[0]), src, toCopy)
-	if sig == 0 {
-		return len(dst), nil
-	}
-
-	faultN, srcN := uintptr(fault), uintptr(src)
-	if faultN < srcN || faultN >= srcN+toCopy {
-		panic(fmt.Sprintf("CopyIn raised signal %d at %#x, which is outside source [%#x, %#x)", sig, faultN, srcN, srcN+toCopy))
-	}
-
-	// memcpy might have ended the copy up to maxRegisterSize bytes before
-	// fault, if an instruction caused a memory access that straddled two
-	// pages, and the second one faulted. Try to copy up to the fault.
-	var done int
-	if faultN-srcN > maxRegisterSize {
-		done = int(faultN - srcN - maxRegisterSize)
-	}
-	n, err := CopyIn(dst[done:int(faultN-srcN)], unsafe.Pointer(srcN+uintptr(done)))
-	done += n
-	if err != nil {
-		return done, err
-	}
-	return done, errorFromFaultSignal(fault, sig)
-}
-
-// CopyOut copies len(src) bytes from src to dst. If returns the number of
-// bytes done and an error if SIGSEGV or SIGBUS is received while writing to
-// dst.
-func CopyOut(dst unsafe.Pointer, src []byte) (int, error) {
-	toCopy := uintptr(len(src))
-	if toCopy == 0 {
-		return 0, nil
-	}
-
-	fault, sig := memcpy(dst, unsafe.Pointer(&src[0]), toCopy)
-	if sig == 0 {
-		return len(src), nil
-	}
-
-	faultN, dstN := uintptr(fault), uintptr(dst)
-	if faultN < dstN || faultN >= dstN+toCopy {
-		panic(fmt.Sprintf("CopyOut raised signal %d at %#x, which is outside destination [%#x, %#x)", sig, faultN, dstN, dstN+toCopy))
-	}
-
-	// memcpy might have ended the copy up to maxRegisterSize bytes before
-	// fault, if an instruction caused a memory access that straddled two
-	// pages, and the second one faulted. Try to copy up to the fault.
-	var done int
-	if faultN-dstN > maxRegisterSize {
-		done = int(faultN - dstN - maxRegisterSize)
-	}
-	n, err := CopyOut(unsafe.Pointer(dstN+uintptr(done)), src[done:int(faultN-dstN)])
-	done += n
-	if err != nil {
-		return done, err
-	}
-	return done, errorFromFaultSignal(fault, sig)
-}
-
-// Copy copies toCopy bytes from src to dst. It returns the number of bytes
-// copied and an error if SIGSEGV or SIGBUS is received while reading from src
-// or writing to dst.
-//
-// Data is copied in order; if [src, src+toCopy) and [dst, dst+toCopy) overlap,
-// the resulting contents of dst are unspecified.
-func Copy(dst, src unsafe.Pointer, toCopy uintptr) (uintptr, error) {
-	if toCopy == 0 {
-		return 0, nil
-	}
-
-	fault, sig := memcpy(dst, src, toCopy)
-	if sig == 0 {
-		return toCopy, nil
-	}
-
-	// Did the fault occur while reading from src or writing to dst?
-	faultN, srcN, dstN := uintptr(fault), uintptr(src), uintptr(dst)
-	faultAfterSrc := ^uintptr(0)
-	if faultN >= srcN {
-		faultAfterSrc = faultN - srcN
-	}
-	faultAfterDst := ^uintptr(0)
-	if faultN >= dstN {
-		faultAfterDst = faultN - dstN
-	}
-	if faultAfterSrc >= toCopy && faultAfterDst >= toCopy {
-		panic(fmt.Sprintf("Copy raised signal %d at %#x, which is outside source [%#x, %#x) and destination [%#x, %#x)", sig, faultN, srcN, srcN+toCopy, dstN, dstN+toCopy))
-	}
-	faultedAfter := faultAfterSrc
-	if faultedAfter > faultAfterDst {
-		faultedAfter = faultAfterDst
-	}
-
-	// memcpy might have ended the copy up to maxRegisterSize bytes before
-	// fault, if an instruction caused a memory access that straddled two
-	// pages, and the second one faulted. Try to copy up to the fault.
-	var done uintptr
-	if faultedAfter > maxRegisterSize {
-		done = faultedAfter - maxRegisterSize
-	}
-	n, err := Copy(unsafe.Pointer(dstN+done), unsafe.Pointer(srcN+done), faultedAfter-done)
-	done += n
-	if err != nil {
-		return done, err
-	}
-	return done, errorFromFaultSignal(fault, sig)
-}
-
-// ZeroOut writes toZero zero bytes to dst. It returns the number of bytes
-// written and an error if SIGSEGV or SIGBUS is received while writing to dst.
-func ZeroOut(dst unsafe.Pointer, toZero uintptr) (uintptr, error) {
-	if toZero == 0 {
-		return 0, nil
-	}
-
-	fault, sig := memclr(dst, toZero)
-	if sig == 0 {
-		return toZero, nil
-	}
-
-	faultN, dstN := uintptr(fault), uintptr(dst)
-	if faultN < dstN || faultN >= dstN+toZero {
-		panic(fmt.Sprintf("ZeroOut raised signal %d at %#x, which is outside destination [%#x, %#x)", sig, faultN, dstN, dstN+toZero))
-	}
-
-	// memclr might have ended the write up to maxRegisterSize bytes before
-	// fault, if an instruction caused a memory access that straddled two
-	// pages, and the second one faulted. Try to write up to the fault.
-	var done uintptr
-	if faultN-dstN > maxRegisterSize {
-		done = faultN - dstN - maxRegisterSize
-	}
-	n, err := ZeroOut(unsafe.Pointer(dstN+done), faultN-dstN-done)
-	done += n
-	if err != nil {
-		return done, err
-	}
-	return done, errorFromFaultSignal(fault, sig)
-}
-
-// SwapUint32 is equivalent to sync/atomic.SwapUint32, except that it returns
-// an error if SIGSEGV or SIGBUS is received while accessing ptr, or if ptr is
-// not aligned to a 4-byte boundary.
-func SwapUint32(ptr unsafe.Pointer, new uint32) (uint32, error) {
-	if addr := uintptr(ptr); addr&3 != 0 {
-		return 0, AlignmentError{addr, 4}
-	}
-	old, sig := swapUint32(ptr, new)
-	return old, errorFromFaultSignal(ptr, sig)
-}
-
-// SwapUint64 is equivalent to sync/atomic.SwapUint64, except that it returns
-// an error if SIGSEGV or SIGBUS is received while accessing ptr, or if ptr is
-// not aligned to an 8-byte boundary.
-func SwapUint64(ptr unsafe.Pointer, new uint64) (uint64, error) {
-	if addr := uintptr(ptr); addr&7 != 0 {
-		return 0, AlignmentError{addr, 8}
-	}
-	old, sig := swapUint64(ptr, new)
-	return old, errorFromFaultSignal(ptr, sig)
-}
-
-// CompareAndSwapUint32 is equivalent to atomicbitops.CompareAndSwapUint32,
-// except that it returns an error if SIGSEGV or SIGBUS is received while
-// accessing ptr, or if ptr is not aligned to a 4-byte boundary.
-func CompareAndSwapUint32(ptr unsafe.Pointer, old, new uint32) (uint32, error) {
-	if addr := uintptr(ptr); addr&3 != 0 {
-		return 0, AlignmentError{addr, 4}
-	}
-	prev, sig := compareAndSwapUint32(ptr, old, new)
-	return prev, errorFromFaultSignal(ptr, sig)
-}
-
-// LoadUint32 is like sync/atomic.LoadUint32, but operates with user memory. It
-// may fail with SIGSEGV or SIGBUS if it is received while reading from ptr.
-//
-// Preconditions: ptr must be aligned to a 4-byte boundary.
-func LoadUint32(ptr unsafe.Pointer) (uint32, error) {
-	if addr := uintptr(ptr); addr&3 != 0 {
-		return 0, AlignmentError{addr, 4}
-	}
-	val, sig := loadUint32(ptr)
-	return val, errorFromFaultSignal(ptr, sig)
-}
-
-func errorFromFaultSignal(addr unsafe.Pointer, sig int32) error {
-	switch sig {
-	case 0:
-		return nil
-	case int32(syscall.SIGSEGV):
-		return SegvError{uintptr(addr)}
-	case int32(syscall.SIGBUS):
-		return BusError{uintptr(addr)}
-	default:
-		panic(fmt.Sprintf("safecopy got unexpected signal %d at address %#x", sig, addr))
-	}
-}
-
-// ReplaceSignalHandler replaces the existing signal handler for the provided
-// signal with the one that handles faults in safecopy-protected functions.
-//
-// It stores the value of the previously set handler in previous.
-//
-// This function will be called on initialization in order to install safecopy
-// handlers for appropriate signals. These handlers will call the previous
-// handler however, and if this is function is being used externally then the
-// same courtesy is expected.
-func ReplaceSignalHandler(sig syscall.Signal, handler uintptr, previous *uintptr) error {
-	var sa struct {
-		handler  uintptr
-		flags    uint64
-		restorer uintptr
-		mask     uint64
-	}
-	const maskLen = 8
-
-	// Get the existing signal handler information, and save the current
-	// handler. Once we replace it, we will use this pointer to fall back to
-	// it when we receive other signals.
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), 0, uintptr(unsafe.Pointer(&sa)), maskLen, 0, 0); e != 0 {
-		return e
-	}
-
-	// Fail if there isn't a previous handler.
-	if sa.handler == 0 {
-		return fmt.Errorf("previous handler for signal %x isn't set", sig)
-	}
-
-	*previous = sa.handler
-
-	// Install our own handler.
-	sa.handler = handler
-	if _, _, e := syscall.RawSyscall6(syscall.SYS_RT_SIGACTION, uintptr(sig), uintptr(unsafe.Pointer(&sa)), 0, maskLen, 0, 0); e != 0 {
-		return e
-	}
-
-	return nil
-}
diff --git a/pkg/sentry/platform/safecopy/sighandler_amd64.s b/pkg/sentry/platform/safecopy/sighandler_amd64.s
deleted file mode 100644
index 475ae48e9..000000000
--- a/pkg/sentry/platform/safecopy/sighandler_amd64.s
+++ /dev/null
@@ -1,133 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "textflag.h"
-
-// The signals handled by sigHandler.
-#define SIGBUS  7
-#define SIGSEGV 11
-
-// Offsets to the registers in context->uc_mcontext.gregs[].
-#define REG_RDI 0x68
-#define REG_RAX 0x90
-#define REG_IP  0xa8
-
-// Offset to the si_addr field of siginfo.
-#define SI_CODE 0x08
-#define SI_ADDR 0x10
-
-// signalHandler is the signal handler for SIGSEGV and SIGBUS signals. It must
-// not be set up as a handler to any other signals.
-//
-// If the instruction causing the signal is within a safecopy-protected
-// function, the signal is handled such that execution resumes in the
-// appropriate fault handling stub with AX containing the faulting address and
-// DI containing the signal number. Otherwise control is transferred to the
-// previously configured signal handler (savedSigSegvHandler or
-// savedSigBusHandler).
-//
-// This function cannot be written in go because it runs whenever a signal is
-// received by the thread (preempting whatever was running), which includes when
-// garbage collector has stopped or isn't expecting any interactions (like
-// barriers).
-//
-// The arguments are the following:
-// DI - The signal number.
-// SI - Pointer to siginfo_t structure.
-// DX - Pointer to ucontext structure.
-TEXT ·signalHandler(SB),NOSPLIT,$0
-	// Check if the signal is from the kernel.
-	MOVQ $0x0, CX
-	CMPL CX, SI_CODE(SI)
-	JGE original_handler
-
-	// Check if RIP is within the area we care about.
-	MOVQ REG_IP(DX), CX
-	CMPQ CX, ·memcpyBegin(SB)
-	JB not_memcpy
-	CMPQ CX, ·memcpyEnd(SB)
-	JAE not_memcpy
-
-	// Modify the context such that execution will resume in the fault
-	// handler.
-	LEAQ handleMemcpyFault(SB), CX
-	JMP handle_fault
-
-not_memcpy:
-	CMPQ CX, ·memclrBegin(SB)
-	JB not_memclr
-	CMPQ CX, ·memclrEnd(SB)
-	JAE not_memclr
-
-	LEAQ handleMemclrFault(SB), CX
-	JMP handle_fault
-
-not_memclr:
-	CMPQ CX, ·swapUint32Begin(SB)
-	JB not_swapuint32
-	CMPQ CX, ·swapUint32End(SB)
-	JAE not_swapuint32
-
-	LEAQ handleSwapUint32Fault(SB), CX
-	JMP handle_fault
-
-not_swapuint32:
-	CMPQ CX, ·swapUint64Begin(SB)
-	JB not_swapuint64
-	CMPQ CX, ·swapUint64End(SB)
-	JAE not_swapuint64
-
-	LEAQ handleSwapUint64Fault(SB), CX
-	JMP handle_fault
-
-not_swapuint64:
-	CMPQ CX, ·compareAndSwapUint32Begin(SB)
-	JB not_casuint32
-	CMPQ CX, ·compareAndSwapUint32End(SB)
-	JAE not_casuint32
-
-	LEAQ handleCompareAndSwapUint32Fault(SB), CX
-	JMP handle_fault
-
-not_casuint32:
-	CMPQ CX, ·loadUint32Begin(SB)
-	JB not_loaduint32
-	CMPQ CX, ·loadUint32End(SB)
-	JAE not_loaduint32
-
-	LEAQ handleLoadUint32Fault(SB), CX
-	JMP handle_fault
-
-not_loaduint32:
-original_handler:
-	// Jump to the previous signal handler, which is likely the golang one.
-	XORQ CX, CX
-	MOVQ ·savedSigBusHandler(SB), AX
-	CMPL DI, $SIGSEGV
-	CMOVQEQ ·savedSigSegVHandler(SB), AX
-	JMP AX
-
-handle_fault:
-	// Entered with the address of the fault handler in RCX; store it in
-	// RIP.
-	MOVQ CX, REG_IP(DX)
-
-	// Store the faulting address in RAX.
-	MOVQ SI_ADDR(SI), CX
-	MOVQ CX, REG_RAX(DX)
-
-	// Store the signal number in EDI.
-	MOVL DI, REG_RDI(DX)
-
-	RET
diff --git a/pkg/sentry/platform/safecopy/sighandler_arm64.s b/pkg/sentry/platform/safecopy/sighandler_arm64.s
deleted file mode 100644
index 53e4ac2c1..000000000
--- a/pkg/sentry/platform/safecopy/sighandler_arm64.s
+++ /dev/null
@@ -1,143 +0,0 @@
-// Copyright 2018 The gVisor Authors.
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-
-#include "textflag.h"
-
-// The signals handled by sigHandler.
-#define SIGBUS 7
-#define SIGSEGV 11
-
-// Offsets to the registers in context->uc_mcontext.gregs[].
-#define REG_R0 0xB8
-#define REG_R1 0xC0
-#define REG_PC 0x1B8
-
-// Offset to the si_addr field of siginfo.
-#define SI_CODE 0x08
-#define SI_ADDR 0x10
-
-// signalHandler is the signal handler for SIGSEGV and SIGBUS signals. It must
-// not be set up as a handler to any other signals.
-//
-// If the instruction causing the signal is within a safecopy-protected
-// function, the signal is handled such that execution resumes in the
-// appropriate fault handling stub with R0 containing the faulting address and
-// R1 containing the signal number. Otherwise control is transferred to the
-// previously configured signal handler (savedSigSegvHandler or
-// savedSigBusHandler).
-//
-// This function cannot be written in go because it runs whenever a signal is
-// received by the thread (preempting whatever was running), which includes when
-// garbage collector has stopped or isn't expecting any interactions (like
-// barriers).
-//
-// The arguments are the following:
-// R0 - The signal number.
-// R1 - Pointer to siginfo_t structure.
-// R2 - Pointer to ucontext structure.
-TEXT ·signalHandler(SB),NOSPLIT,$0
-	// Check if the signal is from the kernel, si_code > 0 means a kernel signal.
-	MOVD SI_CODE(R1), R7
-	CMPW $0x0, R7
-	BLE original_handler
-
-	// Check if PC is within the area we care about.
-	MOVD REG_PC(R2), R7
-	MOVD ·memcpyBegin(SB), R8
-	CMP R8, R7
-	BLO not_memcpy
-	MOVD ·memcpyEnd(SB), R8
-	CMP R8, R7
-	BHS not_memcpy
-
-	// Modify the context such that execution will resume in the fault handler.
-	MOVD $handleMemcpyFault(SB), R7
-	B handle_fault
-
-not_memcpy:
-	MOVD ·memclrBegin(SB), R8
-	CMP R8, R7
-	BLO not_memclr
-	MOVD ·memclrEnd(SB), R8
-	CMP R8, R7
-	BHS not_memclr
-
-	MOVD $handleMemclrFault(SB), R7
-	B handle_fault
-
-not_memclr:
-	MOVD ·swapUint32Begin(SB), R8
-	CMP R8, R7
-	BLO not_swapuint32
-	MOVD ·swapUint32End(SB), R8
-	CMP R8, R7
-	BHS not_swapuint32
-
-	MOVD $handleSwapUint32Fault(SB), R7
-	B handle_fault
-
-not_swapuint32:
-	MOVD ·swapUint64Begin(SB), R8
-	CMP R8, R7
-	BLO not_swapuint64
-	MOVD ·swapUint64End(SB), R8
-	CMP R8, R7
-	BHS not_swapuint64
-
-	MOVD $handleSwapUint64Fault(SB), R7
-	B handle_fault
-
-not_swapuint64:
-	MOVD ·compareAndSwapUint32Begin(SB), R8
-	CMP R8, R7
-	BLO not_casuint32
-	MOVD ·compareAndSwapUint32End(SB), R8
-	CMP R8, R7
-	BHS not_casuint32
-
-	MOVD $handleCompareAndSwapUint32Fault(SB), R7
-	B handle_fault
-
-not_casuint32:
-	MOVD ·loadUint32Begin(SB), R8
-	CMP R8, R7
-	BLO not_loaduint32
-	MOVD ·loadUint32End(SB), R8
-	CMP R8, R7
-	BHS not_loaduint32
-
-	MOVD $handleLoadUint32Fault(SB), R7
-	B handle_fault
-
-not_loaduint32:
-original_handler:
-	// Jump to the previous signal handler, which is likely the golang one.
-	MOVD ·savedSigBusHandler(SB), R7
-	MOVD ·savedSigSegVHandler(SB), R8
-	CMPW $SIGSEGV, R0
-	CSEL EQ, R8, R7, R7
-	B (R7)
-
-handle_fault:
-	// Entered with the address of the fault handler in R7; store it in PC.
-	MOVD R7, REG_PC(R2)
-
-	// Store the faulting address in R0.
-	MOVD SI_ADDR(R1), R7
-	MOVD R7, REG_R0(R2)
-
-	// Store the signal number in R1.
-	MOVW R0, REG_R1(R2)
-
-	RET