Re: [PATCH] MIPS: make userspace mapping young by default
From: 黄沛 <hidden>
Date: 2021-02-04 04:47:10
Also in:
linux-arch, linux-mips
I am ok with it Original Message From: Nicholas Piggin Sent: 2021年2月4日星期四 11:55 To: ambrosehua@gmail.com; Huang Pei; Thomas Bogendoerfer Cc: Andrew Morton; Huacai Chen; Gao Juxin; Jiaxun Yang; linux-arch@vger.kernel.org; linux-mips@vger.kernel.org; linux-mm@kvack.org; Li Xuefeng; Bibo Mao; Paul Burton; Yang Tiezhu; Fuxin Zhang Subject: Re: [PATCH] MIPS: make userspace mapping young by default Excerpts from Huang Pei's message of February 4, 2021 11:39 am:
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>
Could we merge this? For the core code, Reviewed-by: Nicholas Piggin <npiggin@gmail.com>
quoted hunk ↗ jump to hunk
--- arch/mips/mm/cache.c | 30 ++++++++++++++++-------------- include/linux/pgtable.h | 8 -------- mm/memory.c | 3 --- 3 files changed, 16 insertions(+), 25 deletions(-)diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index 23b16bfd97b2..e19cf424bb39 100644 --- a/arch/mips/mm/cache.c +++ b/arch/mips/mm/cache.c@@ -156,29 +156,31 @@ 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)diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 8fcdfa52eb4b..8c042627399a 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h@@ -432,14 +432,6 @@ static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long addres* 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 #endifdiff --git a/mm/memory.c b/mm/memory.c index feff48e1465a..95718a623884 100644 --- a/mm/memory.c +++ b/mm/memory.c@@ -2890,7 +2890,6 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)} 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); /*@@ -3548,7 +3547,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)__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));@@ -3824,7 +3822,6 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct page *page)flush_icache_page(vma, page); entry = mk_pte(page, vma->vm_page_prot); - entry = pte_sw_mkyoung(entry); if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* copy-on-write page */ -- 2.17.1