From 91f1ac731933ac1fe0f9ef30f4c9d06fa4031021 Mon Sep 17 00:00:00 2001
From: Michael Pratt <mpratt@google.com>
Date: Tue, 17 Dec 2019 13:57:39 -0800
Subject: Mark enableCpuidFault nosplit
This is called after fork, so it must be nosplit.
Updates #1408
PiperOrigin-RevId: 286053054
---
pkg/sentry/platform/ptrace/subprocess_amd64.go | 10 ++++++++--
pkg/sentry/platform/ptrace/subprocess_arm64.go | 2 ++
2 files changed, 10 insertions(+), 2 deletions(-)
(limited to 'pkg/sentry/platform')
diff --git a/pkg/sentry/platform/ptrace/subprocess_amd64.go b/pkg/sentry/platform/ptrace/subprocess_amd64.go
index a55cff507..606dc2b1d 100644
--- a/pkg/sentry/platform/ptrace/subprocess_amd64.go
+++ b/pkg/sentry/platform/ptrace/subprocess_amd64.go
@@ -167,8 +167,14 @@ func patchSignalInfo(regs *syscall.PtraceRegs, signalInfo *arch.SignalInfo) {
}
}
-// enableCpuidFault enable cpuid-faulting; this may fail on older kernels or hardware,
-// so we just disregard the result. Host CPUID will be enabled.
+// enableCpuidFault enables cpuid-faulting.
+//
+// This may fail on older kernels or hardware, so we just disregard the result.
+// Host CPUID will be enabled.
+//
+// This is safe to call in an afterFork context.
+//
+//go:nosplit
func enableCpuidFault() {
syscall.RawSyscall6(syscall.SYS_ARCH_PRCTL, linux.ARCH_SET_CPUID, 0, 0, 0, 0, 0)
}
diff --git a/pkg/sentry/platform/ptrace/subprocess_arm64.go b/pkg/sentry/platform/ptrace/subprocess_arm64.go
index aed34e7ee..62a686ee7 100644
--- a/pkg/sentry/platform/ptrace/subprocess_arm64.go
+++ b/pkg/sentry/platform/ptrace/subprocess_arm64.go
@@ -151,6 +151,8 @@ func patchSignalInfo(regs *syscall.PtraceRegs, signalInfo *arch.SignalInfo) {
}
// Noop on arm64.
+//
+//go:nosplit
func enableCpuidFault() {
}
--
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