diff options
| -rw-r--r-- | arch/arm/oprofile/backtrace.c | 46 | ||||
| -rw-r--r-- | arch/i386/oprofile/backtrace.c | 38 | ||||
| -rw-r--r-- | include/linux/mm.h | 1 | ||||
| -rw-r--r-- | mm/memory.c | 29 |
4 files changed, 26 insertions, 88 deletions
diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c index df35c452a8b..7c22c12618c 100644 --- a/arch/arm/oprofile/backtrace.c +++ b/arch/arm/oprofile/backtrace.c @@ -49,42 +49,22 @@ static struct frame_tail* kernel_backtrace(struct frame_tail *tail) static struct frame_tail* user_backtrace(struct frame_tail *tail) { - struct frame_tail buftail; + struct frame_tail buftail[2]; - /* hardware pte might not be valid due to dirty/accessed bit emulation - * so we use copy_from_user and benefit from exception fixups */ - if (copy_from_user(&buftail, tail, sizeof(struct frame_tail))) + /* Also check accessibility of one struct frame_tail beyond */ + if (!access_ok(VERIFY_READ, tail, sizeof(buftail))) + return NULL; + if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail))) return NULL; - oprofile_add_trace(buftail.lr); + oprofile_add_trace(buftail[0].lr); /* frame pointers should strictly progress back up the stack * (towards higher addresses) */ - if (tail >= buftail.fp) + if (tail >= buftail[0].fp) return NULL; - return buftail.fp-1; -} - -/* Compare two addresses and see if they're on the same page */ -#define CMP_ADDR_EQUAL(x,y,offset) ((((unsigned long) x) >> PAGE_SHIFT) \ - == ((((unsigned long) y) + offset) >> PAGE_SHIFT)) - -/* check that the page(s) containing the frame tail are present */ -static int pages_present(struct frame_tail *tail) -{ - struct mm_struct * mm = current->mm; - - if (!check_user_page_readable(mm, (unsigned long)tail)) - return 0; - - if (CMP_ADDR_EQUAL(tail, tail, 8)) - return 1; - - if (!check_user_page_readable(mm, ((unsigned long)tail) + 8)) - return 0; - - return 1; + return buftail[0].fp-1; } /* @@ -118,7 +98,6 @@ static int valid_kernel_stack(struct frame_tail *tail, struct pt_regs *regs) void arm_backtrace(struct pt_regs * const regs, unsigned int depth) { struct frame_tail *tail; - unsigned long last_address = 0; tail = ((struct frame_tail *) regs->ARM_fp) - 1; @@ -132,13 +111,6 @@ void arm_backtrace(struct pt_regs * const regs, unsigned int depth) return; } - while (depth-- && tail && !((unsigned long) tail & 3)) { - if ((!CMP_ADDR_EQUAL(last_address, tail, 0) - || !CMP_ADDR_EQUAL(last_address, tail, 8)) - && !pages_present(tail)) - return; - last_address = (unsigned long) tail; + while (depth-- && tail && !((unsigned long) tail & 3)) tail = user_backtrace(tail); - } } - diff --git a/arch/i386/oprofile/backtrace.c b/arch/i386/oprofile/backtrace.c index 65dfd2edb67..21654be3f73 100644 --- a/arch/i386/oprofile/backtrace.c +++ b/arch/i386/oprofile/backtrace.c @@ -12,6 +12,7 @@ #include <linux/sched.h> #include <linux/mm.h> #include <asm/ptrace.h> +#include <asm/uaccess.h> struct frame_head { struct frame_head * ebp; @@ -21,26 +22,22 @@ struct frame_head { static struct frame_head * dump_backtrace(struct frame_head * head) { - oprofile_add_trace(head->ret); + struct frame_head bufhead[2]; - /* frame pointers should strictly progress back up the stack - * (towards higher addresses) */ - if (head >= head->ebp) + /* Also check accessibility of one struct frame_head beyond */ + if (!access_ok(VERIFY_READ, head, sizeof(bufhead))) + return NULL; + if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead))) return NULL; - return head->ebp; -} - -/* check that the page(s) containing the frame head are present */ -static int pages_present(struct frame_head * head) -{ - struct mm_struct * mm = current->mm; + oprofile_add_trace(bufhead[0].ret); - /* FIXME: only necessary once per page */ - if (!check_user_page_readable(mm, (unsigned long)head)) - return 0; + /* frame pointers should strictly progress back up the stack + * (towards higher addresses) */ + if (head >= bufhead[0].ebp) + return NULL; - return check_user_page_readable(mm, (unsigned long)(head + 1)); + return bufhead[0].ebp; } /* @@ -97,15 +94,6 @@ x86_backtrace(struct pt_regs * const regs, unsigned int depth) return; } -#ifdef CONFIG_SMP - if (!spin_trylock(¤t->mm->page_table_lock)) - return; -#endif - - while (depth-- && head && pages_present(head)) + while (depth-- && head) head = dump_backtrace(head); - -#ifdef CONFIG_SMP - spin_unlock(¤t->mm->page_table_lock); -#endif } diff --git a/include/linux/mm.h b/include/linux/mm.h index 972e2ce8e07..aa8de20e2e8 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -944,7 +944,6 @@ extern struct page * vmalloc_to_page(void *addr); extern unsigned long vmalloc_to_pfn(void *addr); extern struct page * follow_page(struct mm_struct *mm, unsigned long address, int write); -extern int check_user_page_readable(struct mm_struct *mm, unsigned long address); int remap_pfn_range(struct vm_area_struct *, unsigned long, unsigned long, unsigned long, pgprot_t); diff --git a/mm/memory.c b/mm/memory.c index 622a4ef5409..51f7c0a220d 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -809,8 +809,7 @@ unsigned long zap_page_range(struct vm_area_struct *vma, unsigned long address, * Do a quick page-table lookup for a single page. * mm->page_table_lock must be held. */ -static struct page *__follow_page(struct mm_struct *mm, unsigned long address, - int read, int write, int accessed) +struct page *follow_page(struct mm_struct *mm, unsigned long address, int write) { pgd_t *pgd; pud_t *pud; @@ -846,16 +845,12 @@ static struct page *__follow_page(struct mm_struct *mm, unsigned long address, if (pte_present(pte)) { if (write && !pte_write(pte)) goto out; - if (read && !pte_read(pte)) - goto out; pfn = pte_pfn(pte); if (pfn_valid(pfn)) { page = pfn_to_page(pfn); - if (accessed) { - if (write && !pte_dirty(pte) &&!PageDirty(page)) - set_page_dirty(page); - mark_page_accessed(page); - } + if (write && !pte_dirty(pte) &&!PageDirty(page)) + set_page_dirty(page); + mark_page_accessed(page); return page; } } @@ -864,22 +859,6 @@ out: return NULL; } -inline struct page * -follow_page(struct mm_struct *mm, unsigned long address, int write) -{ - return __follow_page(mm, address, 0, write, 1); -} - -/* - * check_user_page_readable() can be called frm niterrupt context by oprofile, - * so we need to avoid taking any non-irq-safe locks - */ -int check_user_page_readable(struct mm_struct *mm, unsigned long address) -{ - return __follow_page(mm, address, 1, 0, 0) != NULL; -} -EXPORT_SYMBOL(check_user_page_readable); - static inline int untouched_anonymous_page(struct mm_struct* mm, struct vm_area_struct *vma, unsigned long address) |