diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-13 11:56:16 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-09-13 11:56:16 -0700 |
| commit | b5df1b3a5637deae352d282b50d4b99d0e2b8d1d (patch) | |
| tree | 5b057e8ac631898ccb52c7e21ab04f6456af3e78 /arch/x86/mm/tlb.c | |
| parent | 9888e4d4831d72a64c4378878ada1a4d7539a790 (diff) | |
| parent | 1278f58cdee63cfbb04e5624474a291c81a7a13b (diff) | |
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"The main changes are the PCID fixes from Andy, but there's also two
hyperv fixes and two paravirt updates"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/hyper-v: Remove duplicated HV_X64_EX_PROCESSOR_MASKS_RECOMMENDED definition
x86/hyper-V: Allocate the IDT entry early in boot
paravirt: Switch maintainer
x86/paravirt: Remove no longer used paravirt functions
x86/mm/64: Initialize CR4.PCIDE early
x86/hibernate/64: Mask off CR3's PCID bits in the saved CR3
x86/mm: Get rid of VM_BUG_ON in switch_tlb_irqs_off()
Diffstat (limited to 'arch/x86/mm/tlb.c')
| -rw-r--r-- | arch/x86/mm/tlb.c | 22 |
1 files changed, 21 insertions, 1 deletions
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 37689a7cc03b..1ab3821f9e26 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -121,8 +121,28 @@ void switch_mm_irqs_off(struct mm_struct *prev, struct mm_struct *next, * hypothetical buggy code that directly switches to swapper_pg_dir * without going through leave_mm() / switch_mm_irqs_off() or that * does something like write_cr3(read_cr3_pa()). + * + * Only do this check if CONFIG_DEBUG_VM=y because __read_cr3() + * isn't free. */ - VM_BUG_ON(__read_cr3() != (__sme_pa(real_prev->pgd) | prev_asid)); +#ifdef CONFIG_DEBUG_VM + if (WARN_ON_ONCE(__read_cr3() != + (__sme_pa(real_prev->pgd) | prev_asid))) { + /* + * If we were to BUG here, we'd be very likely to kill + * the system so hard that we don't see the call trace. + * Try to recover instead by ignoring the error and doing + * a global flush to minimize the chance of corruption. + * + * (This is far from being a fully correct recovery. + * Architecturally, the CPU could prefetch something + * back into an incorrect ASID slot and leave it there + * to cause trouble down the road. It's better than + * nothing, though.) + */ + __flush_tlb_all(); + } +#endif if (real_prev == next) { VM_BUG_ON(this_cpu_read(cpu_tlbstate.ctxs[prev_asid].ctx_id) != |