diff options
Diffstat (limited to 'arch/x86/entry/vdso')
| -rw-r--r-- | arch/x86/entry/vdso/vclock_gettime.c | 17 | ||||
| -rw-r--r-- | arch/x86/entry/vdso/vgetcpu.c | 2 | ||||
| -rw-r--r-- | arch/x86/entry/vdso/vma.c | 2 |
3 files changed, 16 insertions, 5 deletions
diff --git a/arch/x86/entry/vdso/vclock_gettime.c b/arch/x86/entry/vdso/vclock_gettime.c index 98c7d12b945c..4aed41f638bb 100644 --- a/arch/x86/entry/vdso/vclock_gettime.c +++ b/arch/x86/entry/vdso/vclock_gettime.c @@ -1,6 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2006 Andi Kleen, SUSE Labs. - * Subject to the GNU Public License, v.2 * * Fast user context implementation of clock_gettime, gettimeofday, and time. * @@ -128,13 +128,24 @@ notrace static inline u64 vgetcyc(int mode) { if (mode == VCLOCK_TSC) return (u64)rdtsc_ordered(); + + /* + * For any memory-mapped vclock type, we need to make sure that gcc + * doesn't cleverly hoist a load before the mode check. Otherwise we + * might end up touching the memory-mapped page even if the vclock in + * question isn't enabled, which will segfault. Hence the barriers. + */ #ifdef CONFIG_PARAVIRT_CLOCK - else if (mode == VCLOCK_PVCLOCK) + if (mode == VCLOCK_PVCLOCK) { + barrier(); return vread_pvclock(); + } #endif #ifdef CONFIG_HYPERV_TSCPAGE - else if (mode == VCLOCK_HVCLOCK) + if (mode == VCLOCK_HVCLOCK) { + barrier(); return vread_hvclock(); + } #endif return U64_MAX; } diff --git a/arch/x86/entry/vdso/vgetcpu.c b/arch/x86/entry/vdso/vgetcpu.c index f86ab0ae1777..b88a82bbc359 100644 --- a/arch/x86/entry/vdso/vgetcpu.c +++ b/arch/x86/entry/vdso/vgetcpu.c @@ -1,6 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2006 Andi Kleen, SUSE Labs. - * Subject to the GNU Public License, v.2 * * Fast user context implementation of getcpu() */ diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c index babc4e7a519c..8db1f594e8b1 100644 --- a/arch/x86/entry/vdso/vma.c +++ b/arch/x86/entry/vdso/vma.c @@ -1,6 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * Copyright 2007 Andi Kleen, SUSE Labs. - * Subject to the GPL, v.2 * * This contains most of the x86 vDSO kernel-side code. */ |