From 60ec5585496871345c1a8113d7b60ed9d9474866 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Sat, 29 Oct 2005 18:16:34 -0700 Subject: [PATCH] [PATCH] mm: i386 sh sh64 ready for split ptlock Use pte_offset_map_lock, instead of pte_offset_map (or inappropriate pte_offset_kernel) and mm-wide page_table_lock, in sundry arch places. The i386 vm86 mark_screen_rdonly: yes, there was and is an assumption that the screen fits inside the one page table, as indeed it does. The sh __do_page_fault: which handles both kernel faults (without lock) and user mm faults (locked - though it set_pte without locking before). The sh64 flush_cache_range and helpers: which wrongly thought callers held page_table_lock before (only its tlb_start_vma did, and no longer does so); moved the flush loop down, and adjusted the large versus small range decision to consider a range which spans page tables as large. Signed-off-by: Hugh Dickins Acked-by: Paul Mundt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/i386/kernel/vm86.c | 17 +++++------ arch/sh/mm/fault.c | 40 +++++++++++++----------- arch/sh64/mm/cache.c | 68 ++++++++++++++++++----------------------- 3 files changed, 60 insertions(+), 65 deletions(-) diff --git a/arch/i386/kernel/vm86.c b/arch/i386/kernel/vm86.c index 16b48500962..fc1993564f9 100644 --- a/arch/i386/kernel/vm86.c +++ b/arch/i386/kernel/vm86.c @@ -134,17 +134,16 @@ struct pt_regs * fastcall save_v86_state(struct kernel_vm86_regs * regs) return ret; } -static void mark_screen_rdonly(struct task_struct * tsk) +static void mark_screen_rdonly(struct mm_struct *mm) { pgd_t *pgd; pud_t *pud; pmd_t *pmd; - pte_t *pte, *mapped; + pte_t *pte; + spinlock_t *ptl; int i; - preempt_disable(); - spin_lock(&tsk->mm->page_table_lock); - pgd = pgd_offset(tsk->mm, 0xA0000); + pgd = pgd_offset(mm, 0xA0000); if (pgd_none_or_clear_bad(pgd)) goto out; pud = pud_offset(pgd, 0xA0000); @@ -153,16 +152,14 @@ static void mark_screen_rdonly(struct task_struct * tsk) pmd = pmd_offset(pud, 0xA0000); if (pmd_none_or_clear_bad(pmd)) goto out; - pte = mapped = pte_offset_map(pmd, 0xA0000); + pte = pte_offset_map_lock(mm, pmd, 0xA0000, &ptl); for (i = 0; i < 32; i++) { if (pte_present(*pte)) set_pte(pte, pte_wrprotect(*pte)); pte++; } - pte_unmap(mapped); + pte_unmap_unlock(pte, ptl); out: - spin_unlock(&tsk->mm->page_table_lock); - preempt_enable(); flush_tlb(); } @@ -306,7 +303,7 @@ static void do_sys_vm86(struct kernel_vm86_struct *info, struct task_struct *tsk tsk->thread.screen_bitmap = info->screen_bitmap; if (info->flags & VM86_SCREEN_BITMAP) - mark_screen_rdonly(tsk); + mark_screen_rdonly(tsk->mm); __asm__ __volatile__( "xorl %%eax,%%eax; movl %%eax,%%fs; movl %%eax,%%gs\n\t" "movl %0,%%esp\n\t" diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c index 7abba2161da..775f86cd3fe 100644 --- a/arch/sh/mm/fault.c +++ b/arch/sh/mm/fault.c @@ -194,10 +194,13 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, unsigned long address) { unsigned long addrmax = P4SEG; - pgd_t *dir; + pgd_t *pgd; pmd_t *pmd; pte_t *pte; pte_t entry; + struct mm_struct *mm; + spinlock_t *ptl; + int ret = 1; #ifdef CONFIG_SH_KGDB if (kgdb_nofault && kgdb_bus_err_hook) @@ -208,28 +211,28 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, addrmax = P4SEG_STORE_QUE + 0x04000000; #endif - if (address >= P3SEG && address < addrmax) - dir = pgd_offset_k(address); - else if (address >= TASK_SIZE) + if (address >= P3SEG && address < addrmax) { + pgd = pgd_offset_k(address); + mm = NULL; + } else if (address >= TASK_SIZE) return 1; - else if (!current->mm) + else if (!(mm = current->mm)) return 1; else - dir = pgd_offset(current->mm, address); + pgd = pgd_offset(mm, address); - pmd = pmd_offset(dir, address); - if (pmd_none(*pmd)) - return 1; - if (pmd_bad(*pmd)) { - pmd_ERROR(*pmd); - pmd_clear(pmd); + pmd = pmd_offset(pgd, address); + if (pmd_none_or_clear_bad(pmd)) return 1; - } - pte = pte_offset_kernel(pmd, address); + if (mm) + pte = pte_offset_map_lock(mm, pmd, address, &ptl); + else + pte = pte_offset_kernel(pmd, address); + entry = *pte; if (pte_none(entry) || pte_not_present(entry) || (writeaccess && !pte_write(entry))) - return 1; + goto unlock; if (writeaccess) entry = pte_mkdirty(entry); @@ -251,8 +254,11 @@ asmlinkage int __do_page_fault(struct pt_regs *regs, unsigned long writeaccess, set_pte(pte, entry); update_mmu_cache(NULL, address, entry); - - return 0; + ret = 0; +unlock: + if (mm) + pte_unmap_unlock(pte, ptl); + return ret; } void flush_tlb_page(struct vm_area_struct *vma, unsigned long page) diff --git a/arch/sh64/mm/cache.c b/arch/sh64/mm/cache.c index 3b87e25ea77..c0c1b21350d 100644 --- a/arch/sh64/mm/cache.c +++ b/arch/sh64/mm/cache.c @@ -584,32 +584,36 @@ static void sh64_dcache_purge_phy_page(unsigned long paddr) } } -static void sh64_dcache_purge_user_page(struct mm_struct *mm, unsigned long eaddr) +static void sh64_dcache_purge_user_pages(struct mm_struct *mm, + unsigned long addr, unsigned long end) { pgd_t *pgd; pmd_t *pmd; pte_t *pte; pte_t entry; + spinlock_t *ptl; unsigned long paddr; - /* NOTE : all the callers of this have mm->page_table_lock held, so the - following page table traversal is safe even on SMP/pre-emptible. */ - - if (!mm) return; /* No way to find physical address of page */ - pgd = pgd_offset(mm, eaddr); - if (pgd_bad(*pgd)) return; - - pmd = pmd_offset(pgd, eaddr); - if (pmd_none(*pmd) || pmd_bad(*pmd)) return; - - pte = pte_offset_kernel(pmd, eaddr); - entry = *pte; - if (pte_none(entry) || !pte_present(entry)) return; - - paddr = pte_val(entry) & PAGE_MASK; - - sh64_dcache_purge_coloured_phy_page(paddr, eaddr); - + if (!mm) + return; /* No way to find physical address of page */ + + pgd = pgd_offset(mm, addr); + if (pgd_bad(*pgd)) + return; + + pmd = pmd_offset(pgd, addr); + if (pmd_none(*pmd) || pmd_bad(*pmd)) + return; + + pte = pte_offset_map_lock(mm, pmd, addr, &ptl); + do { + entry = *pte; + if (pte_none(entry) || !pte_present(entry)) + continue; + paddr = pte_val(entry) & PAGE_MASK; + sh64_dcache_purge_coloured_phy_page(paddr, addr); + } while (pte++, addr += PAGE_SIZE, addr != end); + pte_unmap_unlock(pte - 1, ptl); } /****************************************************************************/ @@ -668,7 +672,7 @@ static void sh64_dcache_purge_user_range(struct mm_struct *mm, int n_pages; n_pages = ((end - start) >> PAGE_SHIFT); - if (n_pages >= 64) { + if (n_pages >= 64 || ((start ^ (end - 1)) & PMD_MASK)) { #if 1 sh64_dcache_purge_all(); #else @@ -707,20 +711,10 @@ static void sh64_dcache_purge_user_range(struct mm_struct *mm, } #endif } else { - /* 'Small' range */ - unsigned long aligned_start; - unsigned long eaddr; - unsigned long last_page_start; - - aligned_start = start & PAGE_MASK; - /* 'end' is 1 byte beyond the end of the range */ - last_page_start = (end - 1) & PAGE_MASK; - - eaddr = aligned_start; - while (eaddr <= last_page_start) { - sh64_dcache_purge_user_page(mm, eaddr); - eaddr += PAGE_SIZE; - } + /* Small range, covered by a single page table page */ + start &= PAGE_MASK; /* should already be so */ + end = PAGE_ALIGN(end); /* should already be so */ + sh64_dcache_purge_user_pages(mm, start, end); } return; } @@ -880,9 +874,7 @@ void flush_cache_range(struct vm_area_struct *vma, unsigned long start, addresses from the user address space specified by mm, after writing back any dirty data. - Note(1), 'end' is 1 byte beyond the end of the range to flush. - - Note(2), this is called with mm->page_table_lock held.*/ + Note, 'end' is 1 byte beyond the end of the range to flush. */ sh64_dcache_purge_user_range(mm, start, end); sh64_icache_inv_user_page_range(mm, start, end); @@ -898,7 +890,7 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long eaddr, unsigned the I-cache must be searched too in case the page in question is both writable and being executed from (e.g. stack trampolines.) - Note(1), this is called with mm->page_table_lock held. + Note, this is called with pte lock held. */ sh64_dcache_purge_phy_page(pfn << PAGE_SHIFT); -- 2.20.1