From c9caa02c529d5e113e40cbc77254558fcdfa4215 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 12 Mar 2008 03:53:29 +0100 Subject: [PATCH] x86: add set_memory_4k to pageattr.c Add a new function to force split large pages into 4k pages. This is needed for some followup optimizations. I had to add a new field to cpa_data to pass down the information that try_preserve_large_page should not run. Right now no set_page_4k() because I didn't need it and all the specialized users I have in mind would be more comfortable with pure addresses. I also didn't export it because it's unlikely external code needs it. Signed-off-by: Andi Kleen Cc: andreas.herrmann3@amd.com Cc: mingo@elte.hu Signed-off-by: Thomas Gleixner Signed-off-by: Ingo Molnar --- arch/x86/mm/pageattr.c | 20 ++++++++++++++++---- include/asm-x86/cacheflush.h | 1 + 2 files changed, 17 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 270cab2e6030..7d9517abc9af 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -31,6 +31,7 @@ struct cpa_data { int numpages; int flushtlb; unsigned long pfn; + unsigned force_split : 1; }; #ifdef CONFIG_X86_64 @@ -262,6 +263,9 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, int i, do_split = 1; unsigned int level; + if (cpa->force_split) + return 1; + spin_lock_irqsave(&pgd_lock, flags); /* * Check for races, another CPU might have split this page @@ -696,7 +700,8 @@ static inline int cache_attr(pgprot_t attr) } static int change_page_attr_set_clr(unsigned long addr, int numpages, - pgprot_t mask_set, pgprot_t mask_clr) + pgprot_t mask_set, pgprot_t mask_clr, + int force_split) { struct cpa_data cpa; int ret, cache, checkalias; @@ -707,7 +712,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, */ mask_set = canon_pgprot(mask_set); mask_clr = canon_pgprot(mask_clr); - if (!pgprot_val(mask_set) && !pgprot_val(mask_clr)) + if (!pgprot_val(mask_set) && !pgprot_val(mask_clr) && !force_split) return 0; /* Ensure we are PAGE_SIZE aligned */ @@ -724,6 +729,7 @@ static int change_page_attr_set_clr(unsigned long addr, int numpages, cpa.mask_set = mask_set; cpa.mask_clr = mask_clr; cpa.flushtlb = 0; + cpa.force_split = force_split; /* No alias checking for _NX bit modifications */ checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX; @@ -762,13 +768,13 @@ out: static inline int change_page_attr_set(unsigned long addr, int numpages, pgprot_t mask) { - return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0)); + return change_page_attr_set_clr(addr, numpages, mask, __pgprot(0), 0); } static inline int change_page_attr_clear(unsigned long addr, int numpages, pgprot_t mask) { - return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask); + return change_page_attr_set_clr(addr, numpages, __pgprot(0), mask, 0); } int _set_memory_uc(unsigned long addr, int numpages) @@ -847,6 +853,12 @@ int set_memory_np(unsigned long addr, int numpages) return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_PRESENT)); } +int set_memory_4k(unsigned long addr, int numpages) +{ + return change_page_attr_set_clr(addr, numpages, __pgprot(0), + __pgprot(0), 1); +} + int set_pages_uc(struct page *page, int numpages) { unsigned long addr = (unsigned long)page_address(page); diff --git a/include/asm-x86/cacheflush.h b/include/asm-x86/cacheflush.h index 7ab5b520b7bd..cb1d6f8fd003 100644 --- a/include/asm-x86/cacheflush.h +++ b/include/asm-x86/cacheflush.h @@ -45,6 +45,7 @@ int set_memory_nx(unsigned long addr, int numpages); int set_memory_ro(unsigned long addr, int numpages); int set_memory_rw(unsigned long addr, int numpages); int set_memory_np(unsigned long addr, int numpages); +int set_memory_4k(unsigned long addr, int numpages); void clflush_cache_range(void *addr, unsigned int size); -- 2.20.1