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-rw-r--r--pkg/abi/linux/membarrier.go9
-rw-r--r--pkg/sentry/mm/mm.go6
-rw-r--r--pkg/sentry/mm/mm_state_autogen.go3
-rw-r--r--pkg/sentry/mm/syscalls.go12
-rw-r--r--pkg/sentry/syscalls/linux/sys_membarrier.go89
5 files changed, 90 insertions, 29 deletions
diff --git a/pkg/abi/linux/membarrier.go b/pkg/abi/linux/membarrier.go
index 0f3c03e63..4f6021a1d 100644
--- a/pkg/abi/linux/membarrier.go
+++ b/pkg/abi/linux/membarrier.go
@@ -14,7 +14,7 @@
package linux
-// membarrier(2) commands, from include/uapi/linux/membarrier.h
+// membarrier(2) commands, from include/uapi/linux/membarrier.h.
const (
MEMBARRIER_CMD_QUERY = 0
MEMBARRIER_CMD_GLOBAL = (1 << 0)
@@ -24,4 +24,11 @@ const (
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED = (1 << 4)
MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 5)
MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 6)
+ MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ = (1 << 7)
+ MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ = (1 << 8)
+)
+
+// membarrier(2) flags, from include/uapi/linux/membarrier.h.
+const (
+ MEMBARRIER_CMD_FLAG_CPU = (1 << 0)
)
diff --git a/pkg/sentry/mm/mm.go b/pkg/sentry/mm/mm.go
index 43567b92c..92cc87d84 100644
--- a/pkg/sentry/mm/mm.go
+++ b/pkg/sentry/mm/mm.go
@@ -243,6 +243,12 @@ type MemoryManager struct {
//
// membarrierPrivateEnabled is accessed using atomic memory operations.
membarrierPrivateEnabled uint32
+
+ // membarrierRSeqEnabled is non-zero if EnableMembarrierRSeq has previously
+ // been called.
+ //
+ // membarrierRSeqEnabled is accessed using atomic memory operations.
+ membarrierRSeqEnabled uint32
}
// vma represents a virtual memory area.
diff --git a/pkg/sentry/mm/mm_state_autogen.go b/pkg/sentry/mm/mm_state_autogen.go
index 1636e5235..1fe9dfd7f 100644
--- a/pkg/sentry/mm/mm_state_autogen.go
+++ b/pkg/sentry/mm/mm_state_autogen.go
@@ -316,6 +316,7 @@ func (m *MemoryManager) StateFields() []string {
"sleepForActivation",
"vdsoSigReturnAddr",
"membarrierPrivateEnabled",
+ "membarrierRSeqEnabled",
}
}
@@ -350,6 +351,7 @@ func (m *MemoryManager) StateSave(stateSinkObject state.Sink) {
stateSinkObject.Save(20, &m.sleepForActivation)
stateSinkObject.Save(21, &m.vdsoSigReturnAddr)
stateSinkObject.Save(22, &m.membarrierPrivateEnabled)
+ stateSinkObject.Save(23, &m.membarrierRSeqEnabled)
}
func (m *MemoryManager) StateLoad(stateSourceObject state.Source) {
@@ -376,6 +378,7 @@ func (m *MemoryManager) StateLoad(stateSourceObject state.Source) {
stateSourceObject.Load(20, &m.sleepForActivation)
stateSourceObject.Load(21, &m.vdsoSigReturnAddr)
stateSourceObject.Load(22, &m.membarrierPrivateEnabled)
+ stateSourceObject.Load(23, &m.membarrierRSeqEnabled)
stateSourceObject.AfterLoad(m.afterLoad)
}
diff --git a/pkg/sentry/mm/syscalls.go b/pkg/sentry/mm/syscalls.go
index 0a66b1cdd..675efdc7c 100644
--- a/pkg/sentry/mm/syscalls.go
+++ b/pkg/sentry/mm/syscalls.go
@@ -1287,3 +1287,15 @@ func (mm *MemoryManager) EnableMembarrierPrivate() {
func (mm *MemoryManager) IsMembarrierPrivateEnabled() bool {
return atomic.LoadUint32(&mm.membarrierPrivateEnabled) != 0
}
+
+// EnableMembarrierRSeq causes future calls to IsMembarrierRSeqEnabled to
+// return true.
+func (mm *MemoryManager) EnableMembarrierRSeq() {
+ atomic.StoreUint32(&mm.membarrierRSeqEnabled, 1)
+}
+
+// IsMembarrierRSeqEnabled returns true if mm.EnableMembarrierRSeq() has
+// previously been called.
+func (mm *MemoryManager) IsMembarrierRSeqEnabled() bool {
+ return atomic.LoadUint32(&mm.membarrierRSeqEnabled) != 0
+}
diff --git a/pkg/sentry/syscalls/linux/sys_membarrier.go b/pkg/sentry/syscalls/linux/sys_membarrier.go
index 288cd8512..63ee5d435 100644
--- a/pkg/sentry/syscalls/linux/sys_membarrier.go
+++ b/pkg/sentry/syscalls/linux/sys_membarrier.go
@@ -24,47 +24,80 @@ import (
// Membarrier implements syscall membarrier(2).
func Membarrier(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) {
cmd := args[0].Int()
- flags := args[1].Int()
-
- p := t.Kernel().Platform
- if !p.HaveGlobalMemoryBarrier() {
- // Event for applications that want membarrier on a configuration that
- // doesn't support them.
- t.Kernel().EmitUnimplementedEvent(t)
- return 0, nil, syserror.ENOSYS
- }
-
- if flags != 0 {
- return 0, nil, syserror.EINVAL
- }
+ flags := args[1].Uint()
switch cmd {
case linux.MEMBARRIER_CMD_QUERY:
- const supportedCommands = linux.MEMBARRIER_CMD_GLOBAL |
- linux.MEMBARRIER_CMD_GLOBAL_EXPEDITED |
- linux.MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED |
- linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED |
- linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED
+ if flags != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ var supportedCommands uintptr
+ if t.Kernel().Platform.HaveGlobalMemoryBarrier() {
+ supportedCommands |= linux.MEMBARRIER_CMD_GLOBAL |
+ linux.MEMBARRIER_CMD_GLOBAL_EXPEDITED |
+ linux.MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED |
+ linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED |
+ linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED
+ }
+ if t.RSeqAvailable() {
+ supportedCommands |= linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ |
+ linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ
+ }
return supportedCommands, nil, nil
- case linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED:
- if !t.MemoryManager().IsMembarrierPrivateEnabled() {
+ case linux.MEMBARRIER_CMD_GLOBAL, linux.MEMBARRIER_CMD_GLOBAL_EXPEDITED, linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED:
+ if flags != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.Kernel().Platform.HaveGlobalMemoryBarrier() {
+ return 0, nil, syserror.EINVAL
+ }
+ if cmd == linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED && !t.MemoryManager().IsMembarrierPrivateEnabled() {
return 0, nil, syserror.EPERM
}
- fallthrough
- case linux.MEMBARRIER_CMD_GLOBAL, linux.MEMBARRIER_CMD_GLOBAL_EXPEDITED:
- return 0, nil, p.GlobalMemoryBarrier()
+ return 0, nil, t.Kernel().Platform.GlobalMemoryBarrier()
case linux.MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED:
+ if flags != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.Kernel().Platform.HaveGlobalMemoryBarrier() {
+ return 0, nil, syserror.EINVAL
+ }
// no-op
return 0, nil, nil
case linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED:
+ if flags != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.Kernel().Platform.HaveGlobalMemoryBarrier() {
+ return 0, nil, syserror.EINVAL
+ }
t.MemoryManager().EnableMembarrierPrivate()
return 0, nil, nil
- case linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE, linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE:
- // We're aware of these, but they aren't implemented since no platform
- // supports them yet.
- t.Kernel().EmitUnimplementedEvent(t)
- fallthrough
+ case linux.MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ:
+ if flags&^linux.MEMBARRIER_CMD_FLAG_CPU != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.RSeqAvailable() {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.MemoryManager().IsMembarrierRSeqEnabled() {
+ return 0, nil, syserror.EPERM
+ }
+ // MEMBARRIER_CMD_FLAG_CPU and cpu_id are ignored since we don't have
+ // the ability to preempt specific CPUs.
+ return 0, nil, t.Kernel().Platform.PreemptAllCPUs()
+ case linux.MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ:
+ if flags != 0 {
+ return 0, nil, syserror.EINVAL
+ }
+ if !t.RSeqAvailable() {
+ return 0, nil, syserror.EINVAL
+ }
+ t.MemoryManager().EnableMembarrierRSeq()
+ return 0, nil, nil
default:
+ // Probably a command we don't implement.
+ t.Kernel().EmitUnimplementedEvent(t)
return 0, nil, syserror.EINVAL
}
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-13 15:02:16 +0000