MIPS page fault path takes 3 exceptions (1 TLB Miss + 2 TLB Invalid), but the 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 and covers both no-rixi and rixi MIPS CPUS +. clean up cpu_has_rixi case in setup_protection_map with PAGE_*_XI, since only _PAGE_NO_EXEC(eXecute Inhibit) provide additional control while _PAGE_NO_READ equals _PAGE_READ for no-rixi MIPS CPUs; [1]: https://lkml.kernel.org/lkml/1591416169-26666-1-git-send-email -maobibo@xxxxxxxxxxx/ --- V4: - clean up cpu_has_rixi case V3: - reformat with whitespace cleaned up following Thomas's advice V2: - remove unused asm-generic definition of pte_sw_mkyoung following Mao's advice --- --- arch/mips/include/asm/pgtable.h | 15 ++++++--- arch/mips/mm/cache.c | 55 +++++++++++++++++---------------- include/linux/pgtable.h | 8 ----- mm/memory.c | 3 -- 4 files changed, 39 insertions(+), 42 deletions(-) diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h index e5ef0fdd4838..3712d9d683f1 100644 --- a/arch/mips/include/asm/pgtable.h +++ b/arch/mips/include/asm/pgtable.h @@ -27,11 +27,20 @@ struct vm_area_struct; #define PAGE_NONE __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \ _page_cachable_default) +#define PAGE_NONE_XI __pgprot(_PAGE_PRESENT | _PAGE_NO_READ | \ + _PAGE_NO_EXEC | _page_cachable_default) #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \ - _page_cachable_default) + __READABLE | _page_cachable_default) +#define PAGE_SHARED_XI __pgprot(_PAGE_PRESENT | _PAGE_WRITE | __READABLE | \ + _PAGE_NO_EXEC | _page_cachable_default) #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_NO_EXEC | \ + __READABLE | _page_cachable_default) +#define PAGE_READONLY __pgprot(_PAGE_PRESENT | __READABLE | \ _page_cachable_default) -#define PAGE_READONLY __pgprot(_PAGE_PRESENT | \ +#define PAGE_READONLY_XI __pgprot(_PAGE_PRESENT | __READABLE | \ + _PAGE_NO_EXEC | _page_cachable_default) +#define PAGE_WRITEONLY_XI __pgprot(_PAGE_PRESENT | _PAGE_WRITE | \ + _PAGE_NO_EXEC | _PAGE_NO_READ | \ _page_cachable_default) #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \ _PAGE_GLOBAL | _page_cachable_default) @@ -412,8 +421,6 @@ static inline pte_t pte_mkyoung(pte_t pte) return pte; } -#define pte_sw_mkyoung pte_mkyoung - #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; } diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index 3e81ba000096..e0488030c76e 100644 --- a/arch/mips/mm/cache.c +++ b/arch/mips/mm/cache.c @@ -158,35 +158,36 @@ EXPORT_SYMBOL(_page_cachable_default); static inline void setup_protection_map(void) { if (cpu_has_rixi) { - protection_map[0] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[1] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[2] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[3] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[4] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - protection_map[5] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - protection_map[6] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - protection_map[7] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - - protection_map[8] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[9] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[10] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ); - protection_map[11] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); - protection_map[12] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - protection_map[13] = __pgprot(_page_cachable_default | _PAGE_PRESENT); - protection_map[14] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE); - protection_map[15] = __pgprot(_page_cachable_default | _PAGE_PRESENT | _PAGE_WRITE); + protection_map[0] = PAGE_NONE_XI; + protection_map[1] = PAGE_COPY; + protection_map[2] = PAGE_NONE_XI; + protection_map[3] = PAGE_COPY; + protection_map[4] = PAGE_READONLY; + protection_map[5] = PAGE_READONLY; + protection_map[6] = PAGE_READONLY; + protection_map[7] = PAGE_READONLY; + + protection_map[8] = PAGE_NONE_XI; + protection_map[9] = PAGE_COPY; + protection_map[10] = PAGE_WRITEONLY_XI; + protection_map[11] = PAGE_SHARED_XI; + protection_map[12] = PAGE_READONLY; + protection_map[13] = PAGE_READONLY; + protection_map[14] = PAGE_READONLY_XI; + protection_map[15] = PAGE_READONLY_XI; + } else { - protection_map[0] = PAGE_NONE; - protection_map[1] = PAGE_READONLY; - protection_map[2] = PAGE_COPY; - protection_map[3] = PAGE_COPY; - protection_map[4] = PAGE_READONLY; - protection_map[5] = PAGE_READONLY; - protection_map[6] = PAGE_COPY; - protection_map[7] = PAGE_COPY; - protection_map[8] = PAGE_NONE; - protection_map[9] = PAGE_READONLY; + protection_map[0] = PAGE_NONE; + protection_map[1] = PAGE_READONLY; + protection_map[2] = PAGE_COPY; + protection_map[3] = PAGE_COPY; + protection_map[4] = PAGE_READONLY; + protection_map[5] = PAGE_READONLY; + protection_map[6] = PAGE_COPY; + protection_map[7] = PAGE_COPY; + protection_map[8] = PAGE_NONE; + protection_map[9] = PAGE_READONLY; protection_map[10] = PAGE_SHARED; protection_map[11] = PAGE_SHARED; protection_map[12] = PAGE_READONLY; diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h index 38c33eabea89..c0326efbaa12 100644 --- a/include/linux/pgtable.h +++ b/include/linux/pgtable.h @@ -377,14 +377,6 @@ 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 #endif diff --git a/mm/memory.c b/mm/memory.c index 589afe45d0b3..95d85d03b0a2 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2877,7 +2877,6 @@ 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); /* * Clear the pte entry and flush it first, before updating the @@ -3533,7 +3532,6 @@ 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)); @@ -3809,7 +3807,6 @@ 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
