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Date: Fri, 9 Mar 2018 16:18:28 -0800 From: Greg Kroah-Hartman <gregkh@...uxfoundation.org> To: linux-kernel@...r.kernel.org Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>, stable@...r.kernel.org, Andy Lutomirski <luto@...nel.org>, Nadav Amit <nadav.amit@...il.com>, Thomas Gleixner <tglx@...utronix.de>, Andrew Morton <akpm@...ux-foundation.org>, Arjan van de Ven <arjan@...ux.intel.com>, Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...el.com>, Linus Torvalds <torvalds@...ux-foundation.org>, Mel Gorman <mgorman@...e.de>, Peter Zijlstra <peterz@...radead.org>, Rik van Riel <riel@...hat.com>, linux-mm@...ck.org, Ingo Molnar <mingo@...nel.org>, Tim Chen <tim.c.chen@...ux.intel.com> Subject: [PATCH 4.9 28/65] x86/mm: Give each mm TLB flush generation a unique ID 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Andy Lutomirski <luto@...nel.org> commit f39681ed0f48498b80455095376f11535feea332 upstream. This adds two new variables to mmu_context_t: ctx_id and tlb_gen. ctx_id uniquely identifies the mm_struct and will never be reused. For a given mm_struct (and hence ctx_id), tlb_gen is a monotonic count of the number of times that a TLB flush has been requested. The pair (ctx_id, tlb_gen) can be used as an identifier for TLB flush actions and will be used in subsequent patches to reliably determine whether all needed TLB flushes have occurred on a given CPU. This patch is split out for ease of review. By itself, it has no real effect other than creating and updating the new variables. Signed-off-by: Andy Lutomirski <luto@...nel.org> Reviewed-by: Nadav Amit <nadav.amit@...il.com> Reviewed-by: Thomas Gleixner <tglx@...utronix.de> Cc: Andrew Morton <akpm@...ux-foundation.org> Cc: Arjan van de Ven <arjan@...ux.intel.com> Cc: Borislav Petkov <bp@...en8.de> Cc: Dave Hansen <dave.hansen@...el.com> Cc: Linus Torvalds <torvalds@...ux-foundation.org> Cc: Mel Gorman <mgorman@...e.de> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Rik van Riel <riel@...hat.com> Cc: linux-mm@...ck.org Link: http://lkml.kernel.org/r/413a91c24dab3ed0caa5f4e4d017d87b0857f920.1498751203.git.luto@kernel.org Signed-off-by: Ingo Molnar <mingo@...nel.org> Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org> --- arch/x86/include/asm/mmu.h | 15 +++++++++++++-- arch/x86/include/asm/mmu_context.h | 5 +++++ arch/x86/mm/tlb.c | 2 ++ 3 files changed, 20 insertions(+), 2 deletions(-) --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -3,12 +3,18 @@ #include <linux/spinlock.h> #include <linux/mutex.h> +#include <linux/atomic.h> /* - * The x86 doesn't have a mmu context, but - * we put the segment information here. + * x86 has arch-specific MMU state beyond what lives in mm_struct. */ typedef struct { + /* + * ctx_id uniquely identifies this mm_struct. A ctx_id will never + * be reused, and zero is not a valid ctx_id. + */ + u64 ctx_id; + #ifdef CONFIG_MODIFY_LDT_SYSCALL struct ldt_struct *ldt; #endif @@ -33,6 +39,11 @@ typedef struct { #endif } mm_context_t; +#define INIT_MM_CONTEXT(mm) \ + .context = { \ + .ctx_id = 1, \ + } + void leave_mm(int cpu); #endif /* _ASM_X86_MMU_H */ --- a/arch/x86/include/asm/mmu_context.h +++ b/arch/x86/include/asm/mmu_context.h @@ -12,6 +12,9 @@ #include <asm/tlbflush.h> #include <asm/paravirt.h> #include <asm/mpx.h> + +extern atomic64_t last_mm_ctx_id; + #ifndef CONFIG_PARAVIRT static inline void paravirt_activate_mm(struct mm_struct *prev, struct mm_struct *next) @@ -106,6 +109,8 @@ static inline void enter_lazy_tlb(struct static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { + mm->context.ctx_id = atomic64_inc_return(&last_mm_ctx_id); + #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { /* pkey 0 is the default and always allocated */ --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -29,6 +29,8 @@ * Implement flush IPI by CALL_FUNCTION_VECTOR, Alex Shi */ +atomic64_t last_mm_ctx_id = ATOMIC64_INIT(1); + struct flush_tlb_info { struct mm_struct *flush_mm; unsigned long flush_start;
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