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authorAndy Lutomirski <luto@kernel.org>2017-09-06 19:54:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-09-06 20:12:57 -0700
commit72c0098d92cedb11c7e0151e84918840a4e96b31 (patch)
treec7ccad396f1c6aa6d0a647cd75a2c9b50406ba8f /arch/x86/include/asm
parent80cee03bf1d626db0278271b505d7f5febb37bba (diff)
x86/mm: Reinitialize TLB state on hotplug and resume
When Linux brings a CPU down and back up, it switches to init_mm and then loads swapper_pg_dir into CR3. With PCID enabled, this has the side effect of masking off the ASID bits in CR3. This can result in some confusion in the TLB handling code. If we bring a CPU down and back up with any ASID other than 0, we end up with the wrong ASID active on the CPU after resume. This could cause our internal state to become corrupt, although major corruption is unlikely because init_mm doesn't have any user pages. More obviously, if CONFIG_DEBUG_VM=y, we'll trip over an assertion in the next context switch. The result of *that* is a failure to resume from suspend with probability 1 - 1/6^(cpus-1). Fix it by reinitializing cpu_tlbstate on resume and CPU bringup. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Jiri Kosina <jikos@kernel.org> Fixes: 10af6235e0d3 ("x86/mm: Implement PCID based optimization: try to preserve old TLB entries using PCID") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/include/asm')
-rw-r--r--arch/x86/include/asm/tlbflush.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d23e61dc0640..4893abf7f74f 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -198,6 +198,8 @@ static inline void cr4_set_bits_and_update_boot(unsigned long mask)
cr4_set_bits(mask);
}
+extern void initialize_tlbstate_and_flush(void);
+
static inline void __native_flush_tlb(void)
{
/*

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