From: Peter Zijlstra <peterz@infradead.org> mainline inclusion from mainline-5.2-rc1 commit a30e32bd79e924f460b8b83408d88af34a402f6d category: feature bugzilla: NA CVE:NA -------------------------------- When an architecture does not have (an efficient) flush_tlb_range(), but instead always uses full TLB invalidates, the current generic tlb_flush() is sub-optimal, for it will generate extra flushes in order to keep the range small. But if we cannot do range flushes, that is a moot concern. Optionally provide this simplified default. No change in behavior intended. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Will Deacon <will.deacon@arm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@surriel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Chen Jun <chenjun102@huawei.com> Reviewed-by: Hanjun Guo <guohanjun@huawei.com> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> --- include/asm-generic/tlb.h | 41 ++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 088af23c93b2..a88082b4be5c 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -111,7 +111,8 @@ * returns the smallest TLB entry size unmapped in this range. * * If an architecture does not provide tlb_flush() a default implementation - * based on flush_tlb_range() will be used. + * based on flush_tlb_range() will be used, unless MMU_GATHER_NO_RANGE is + * specified, in which case we'll default to flush_tlb_mm(). * * Additionally there are a few opt-in features: * @@ -137,6 +138,9 @@ * the page-table pages. Required if you use HAVE_RCU_TABLE_FREE and your * architecture uses the Linux page-tables natively. * + * MMU_GATHER_NO_RANGE + * + * Use this if your architecture lacks an efficient flush_tlb_range(). */ #ifdef CONFIG_HAVE_RCU_TABLE_FREE @@ -297,12 +301,45 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb) */ } +#ifdef CONFIG_MMU_GATHER_NO_RANGE + +#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma) +#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma() +#endif + +/* + * When an architecture does not have efficient means of range flushing TLBs + * there is no point in doing intermediate flushes on tlb_end_vma() to keep the + * range small. We equally don't have to worry about page granularity or other + * things. + * + * All we need to do is issue a full flush for any !0 range. + */ +static inline void tlb_flush(struct mmu_gather *tlb) +{ + if (tlb->end) + flush_tlb_mm(tlb->mm); +} + +static inline void +tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } + +#define tlb_end_vma tlb_end_vma +static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { } + +#else /* CONFIG_MMU_GATHER_NO_RANGE */ + #ifndef tlb_flush #if defined(tlb_start_vma) || defined(tlb_end_vma) #error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma() #endif +/* + * When an architecture does not provide its own tlb_flush() implementation + * but does have a reasonably efficient flush_vma_range() implementation + * use that. + */ static inline void tlb_flush(struct mmu_gather *tlb) { if (tlb->fullmm || tlb->need_flush_all) { @@ -343,6 +380,8 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { } #endif +#endif /* CONFIG_MMU_GATHER_NO_RANGE */ + static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb) { if (!tlb->end) -- 2.25.1