diff options
| -rw-r--r-- | pkg/abi/linux/membarrier.go | 9 | ||||
| -rw-r--r-- | pkg/sentry/mm/mm.go | 6 | ||||
| -rw-r--r-- | pkg/sentry/mm/mm_state_autogen.go | 3 | ||||
| -rw-r--r-- | pkg/sentry/mm/syscalls.go | 12 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/sys_membarrier.go | 89 |
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 } } |