On 03/07/2018 09:37 AM, gregkh@xxxxxxxxxxxxxxxxxxx wrote: > > This is a note to let you know that I've just added the patch titled > > x86/mm: Give each mm TLB flush generation a unique ID > > to the 4.9-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > x86-mm-give-each-mm-tlb-flush-generation-a-unique-id.patch > and it can be found in the queue-4.9 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. > > > From f39681ed0f48498b80455095376f11535feea332 Mon Sep 17 00:00:00 2001 > From: Andy Lutomirski <luto@xxxxxxxxxx> > Date: Thu, 29 Jun 2017 08:53:15 -0700 > Subject: x86/mm: Give each mm TLB flush generation a unique ID > > From: Andy Lutomirski <luto@xxxxxxxxxx> > > 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 Greg, I've only pulled the unique ctx_id part of the original patch and not the tlb_gen changes. The unique ctx_id is a very simple change without needing other related changes that tlb_gen will require. You may want to update the comment to reflect this. > 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@xxxxxxxxxx> > Reviewed-by: Nadav Amit <nadav.amit@xxxxxxxxx> > Reviewed-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxxxx> > Cc: Dave Hansen <dave.hansen@xxxxxxxxx> > Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Cc: Mel Gorman <mgorman@xxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxx> > Cc: linux-mm@xxxxxxxxx > Link: http://lkml.kernel.org/r/413a91c24dab3ed0caa5f4e4d017d87b0857f920.1498751203.git.luto@xxxxxxxxxx > Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> > Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > > --- > 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; > > > Patches currently in stable-queue which might be from luto@xxxxxxxxxx are > > queue-4.9/nospec-allow-index-argument-to-have-const-qualified-type.patch > queue-4.9/x86-speculation-use-indirect-branch-prediction-barrier-in-context-switch.patch > queue-4.9/x86-mm-give-each-mm-tlb-flush-generation-a-unique-id.patch >