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-rw-r--r--arch/arm/oprofile/backtrace.c46
-rw-r--r--arch/i386/oprofile/backtrace.c38
-rw-r--r--include/linux/mm.h1
-rw-r--r--mm/memory.c29
4 files changed, 26 insertions, 88 deletions
diff --git a/arch/arm/oprofile/backtrace.c b/arch/arm/oprofile/backtrace.c
index df35c452a8bf..7c22c12618cc 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 65dfd2edb671..21654be3f73f 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(&current->mm->page_table_lock))
- return;
-#endif
-
- while (depth-- && head && pages_present(head))
+ while (depth-- && head)
head = dump_backtrace(head);
-
-#ifdef CONFIG_SMP
- spin_unlock(&current->mm->page_table_lock);
-#endif
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 972e2ce8e07c..aa8de20e2e80 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 622a4ef5409f..51f7c0a220d4 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)