Prepare for supporting cross compilation.

PiperOrigin-RevId: 346496532

5 files changed, 37 insertions, 6 deletions

diff --git a/pkg/flipcall/BUILD b/pkg/flipcall/BUILD
index aa8e4e1f3..cc31d0175 100644
--- a/pkg/flipcall/BUILD
+++ b/pkg/flipcall/BUILD
@@ -11,7 +11,8 @@ go_library(
         "futex_linux.go",
         "io.go",
         "packet_window_allocator.go",
-        "packet_window_mmap.go",
+        "packet_window_mmap_amd64.go",
+        "packet_window_mmap_arm64.go",
     ],
     visibility = ["//visibility:public"],
     deps = [
diff --git a/pkg/flipcall/packet_window_mmap.go b/pkg/flipcall/packet_window_mmap_amd64.go
index 869183b11..869183b11 100644
--- a/pkg/flipcall/packet_window_mmap.go
+++ b/pkg/flipcall/packet_window_mmap_amd64.go
diff --git a/pkg/flipcall/packet_window_mmap_arm64.go b/pkg/flipcall/packet_window_mmap_arm64.go
new file mode 100644
index 000000000..b9c9c44f6
--- /dev/null
+++ b/pkg/flipcall/packet_window_mmap_arm64.go
@@ -0,0 +1,27 @@
+// Copyright 2020 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.
+
+// +build arm64
+
+package flipcall
+
+import (
+	"syscall"
+)
+
+// Return a memory mapping of the pwd in memory that can be shared outside the sandbox.
+func packetWindowMmap(pwd PacketWindowDescriptor) (uintptr, syscall.Errno) {
+	m, _, err := syscall.RawSyscall6(syscall.SYS_MMAP, 0, uintptr(pwd.Length), syscall.PROT_READ|syscall.PROT_WRITE, syscall.MAP_SHARED, uintptr(pwd.FD), uintptr(pwd.Offset))
+	return m, err
+}
diff --git a/pkg/sentry/platform/ring0/BUILD b/pkg/sentry/platform/ring0/BUILD
index 5d01d21dd..2852b7387 100644
--- a/pkg/sentry/platform/ring0/BUILD
+++ b/pkg/sentry/platform/ring0/BUILD
@@ -1,4 +1,4 @@
-load("//tools:defs.bzl", "go_library")
+load("//tools:defs.bzl", "arch_genrule", "go_library")
 load("//tools/go_generics:defs.bzl", "go_template", "go_template_instance")
 
 package(licenses = ["notice"])
@@ -39,19 +39,19 @@ go_template_instance(
     template = ":defs_arm64",
 )
 
-genrule(
+arch_genrule(
     name = "entry_impl_amd64",
     srcs = ["entry_amd64.s"],
     outs = ["entry_impl_amd64.s"],
-    cmd = "(echo -e '// build +amd64\\n' && $(location //pkg/sentry/platform/ring0/gen_offsets) && cat $(SRCS)) > $@",
+    cmd = "(echo -e '// build +amd64\\n' && QEMU $(location //pkg/sentry/platform/ring0/gen_offsets) && cat $(location entry_amd64.s)) > $@",
     tools = ["//pkg/sentry/platform/ring0/gen_offsets"],
 )
 
-genrule(
+arch_genrule(
     name = "entry_impl_arm64",
     srcs = ["entry_arm64.s"],
     outs = ["entry_impl_arm64.s"],
-    cmd = "(echo -e '// build +arm64\\n' && $(location //pkg/sentry/platform/ring0/gen_offsets) && cat $(SRCS)) > $@",
+    cmd = "(echo -e '// build +arm64\\n' && QEMU $(location //pkg/sentry/platform/ring0/gen_offsets) && cat $(location entry_arm64.s)) > $@",
     tools = ["//pkg/sentry/platform/ring0/gen_offsets"],
 )
 
diff --git a/pkg/sentry/platform/ring0/gen_offsets/BUILD b/pkg/sentry/platform/ring0/gen_offsets/BUILD
index 9742308d8..a9703baf6 100644
--- a/pkg/sentry/platform/ring0/gen_offsets/BUILD
+++ b/pkg/sentry/platform/ring0/gen_offsets/BUILD
@@ -24,6 +24,9 @@ go_binary(
         "defs_impl_arm64.go",
         "main.go",
     ],
+    # Use the libc malloc to avoid any extra dependencies. This is required to
+    # pass the sentry deps test.
+    system_malloc = True,
     visibility = [
         "//pkg/sentry/platform/kvm:__pkg__",
         "//pkg/sentry/platform/ring0:__pkg__",