Re: [PATCH] MIPS: make userspace mapping young by default
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2021-02-05 23:41:10
Also in:
linux-arch, linux-mips
On Thu, 4 Feb 2021 16:22:39 +0100 Thomas Bogendoerfer [off-list ref] wrote:
On Thu, Feb 04, 2021 at 09:39:42AM +0800, Huang Pei wrote:quoted
MIPS page fault path(except huge page) takes 3 exceptions (1 TLB Miss + 2 TLB Invalid), butthe second TLB Invalid exception is just triggered by __update_tlb from do_page_fault writing tlb without _PAGE_VALID set. With this patch, user space mapping prot is made young by default (with both _PAGE_VALID and _PAGE_YOUNG set), and it only take 1 TLB Miss + 1 TLB Invalid exception Remove pte_sw_mkyoung without polluting MM code and make page fault delay of MIPS on par with other architecture Signed-off-by: Huang Pei <redacted> --- arch/mips/mm/cache.c | 30 ++++++++++++++++-------------- include/linux/pgtable.h | 8 -------- mm/memory.c | 3 --- 3 files changed, 16 insertions(+), 25 deletions(-)Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Andrew, can you take this patch through your tree ?
Sure. I'll drop Christophe's "mm/memory.c: remove pte_sw_mkyoung()" (https://lkml.kernel.org/r/f302ef92c48d1f08a0459aaee1c568ca11213814.1612345700.git.christophe.leroy@csgroup.eu) in favour of this one. I changed this patch a bit due to other changes in -next. Please check do_set_pte(). From: Huang Pei <redacted> Subject: MIPS: make userspace mapping young by default MIPS page fault path(except huge page) takes 3 exceptions (1 TLB Miss + 2 TLB Invalid), butthe second TLB Invalid exception is just triggered by __update_tlb from do_page_fault writing tlb without _PAGE_VALID set. With this patch, user space mapping prot is made young by default (with both _PAGE_VALID and _PAGE_YOUNG set), and it only take 1 TLB Miss + 1 TLB Invalid exception Remove pte_sw_mkyoung without polluting MM code and make page fault delay of MIPS on par with other architecture Link: https://lkml.kernel.org/r/20210204013942.8398-1-huangpei@loongson.cn Signed-off-by: Huang Pei <redacted> Reviewed-by: Nicholas Piggin <npiggin@gmail.com> Acked-by: <redacted> Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: <redacted> Cc: Bibo Mao <maobibo@loongson.cn> Cc: Jiaxun Yang <jiaxun.yang@flygoat.com> Cc: Paul Burton <paulburton@kernel.org> Cc: Li Xuefeng <redacted> Cc: Yang Tiezhu <yangtiezhu@loongson.cn> Cc: Gao Juxin <redacted> Cc: Fuxin Zhang <redacted> Cc: Huacai Chen <redacted> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> --- arch/mips/mm/cache.c | 30 ++++++++++++++++-------------- include/linux/pgtable.h | 8 -------- mm/memory.c | 4 ---- 3 files changed, 16 insertions(+), 26 deletions(-)
--- a/arch/mips/mm/cache.c~mips-make-userspace-mapping-young-by-default
+++ a/arch/mips/mm/cache.c@@ -157,29 +157,31 @@ unsigned long _page_cachable_default; EXPORT_SYMBOL(_page_cachable_default); #define PM(p) __pgprot(_page_cachable_default | (p)) +#define PVA(p) PM(_PAGE_VALID | _PAGE_ACCESSED | (p)) static inline void setup_protection_map(void) { protection_map[0] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[1] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[2] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[3] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[4] = PM(_PAGE_PRESENT); - protection_map[5] = PM(_PAGE_PRESENT); - protection_map[6] = PM(_PAGE_PRESENT); - protection_map[7] = PM(_PAGE_PRESENT); + protection_map[1] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[2] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[3] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[4] = PVA(_PAGE_PRESENT); + protection_map[5] = PVA(_PAGE_PRESENT); + protection_map[6] = PVA(_PAGE_PRESENT); + protection_map[7] = PVA(_PAGE_PRESENT); protection_map[8] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[9] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | + protection_map[9] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[10] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ); - protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); - protection_map[12] = PM(_PAGE_PRESENT); - protection_map[13] = PM(_PAGE_PRESENT); - protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE); - protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE); + protection_map[11] = PVA(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); + protection_map[12] = PVA(_PAGE_PRESENT); + protection_map[13] = PVA(_PAGE_PRESENT); + protection_map[14] = PVA(_PAGE_PRESENT); + protection_map[15] = PVA(_PAGE_PRESENT); } +#undef _PVA #undef PM void cpu_cache_init(void) --- a/include/linux/pgtable.h~mips-make-userspace-mapping-young-by-default +++ a/include/linux/pgtable.h
@@ -432,14 +432,6 @@ static inline void ptep_set_wrprotect(st * To be differentiate with macro pte_mkyoung, this macro is used on platforms * where software maintains page access bit. */ -#ifndef pte_sw_mkyoung -static inline pte_t pte_sw_mkyoung(pte_t pte) -{ - return pte; -} -#define pte_sw_mkyoung pte_sw_mkyoung -#endif - #ifndef pte_savedwrite #define pte_savedwrite pte_write #endif --- a/mm/memory.c~mips-make-userspace-mapping-young-by-default +++ a/mm/memory.c
@@ -2902,7 +2902,6 @@ static vm_fault_t wp_page_copy(struct vm } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); - entry = pte_sw_mkyoung(entry); entry = maybe_mkwrite(pte_mkdirty(entry), vma); /*
@@ -3560,7 +3559,6 @@ static vm_fault_t do_anonymous_page(stru __SetPageUptodate(page); entry = mk_pte(page, vma->vm_page_prot); - entry = pte_sw_mkyoung(entry); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry));
@@ -3745,8 +3743,6 @@ void do_set_pte(struct vm_fault *vmf, st if (prefault && arch_wants_old_prefaulted_pte()) entry = pte_mkold(entry); - else - entry = pte_sw_mkyoung(entry); if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma);
_