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[PATCH] i386: Use probe_kernel_address instead of __get_user in fault paths

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Makes the intention of the code cleaner to read and avoids
a potential deadlock on mmap_sem. Also change the types of
the arguments to not include __user because they're really
not user addresses.

Signed-off-by: Andi Kleen <ak@suse.de>
This commit is contained in:
Andi Kleen
2006-12-07 02:14:06 +01:00
committed by Andi Kleen
parent ab2bf0c1c6
commit 11a4180c0b
2 changed files with 19 additions and 17 deletions
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12
arch/i386/mm/fault.c
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@@ -22,9 +22,9 @@
#include <linux/highmem.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/desc.h>
#include <asm/kdebug.h>
#include <asm/segment.h>
@@ -167,7 +167,7 @@ static inline unsigned long get_segment_eip(struct pt_regs *regs,
static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
{
unsigned long limit;
unsigned long instr = get_segment_eip (regs, &limit);
unsigned char *instr = (unsigned char *)get_segment_eip (regs, &limit);
int scan_more = 1;
int prefetch = 0;
int i;
@@ -177,9 +177,9 @@ static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
unsigned char instr_hi;
unsigned char instr_lo;
if (instr > limit)
if (instr > (unsigned char *)limit)
break;
if (__get_user(opcode, (unsigned char __user *) instr))
if (probe_kernel_address(instr, opcode))
break;
instr_hi = opcode & 0xf0;
@@ -204,9 +204,9 @@ static int __is_prefetch(struct pt_regs *regs, unsigned long addr)
case 0x00:
/* Prefetch instruction is 0x0F0D or 0x0F18 */
scan_more = 0;
if (instr > limit)
if (instr > (unsigned char *)limit)
break;
if (__get_user(opcode, (unsigned char __user *) instr))
if (probe_kernel_address(instr, opcode))
break;
prefetch = (instr_lo == 0xF) &&
(opcode == 0x0D || opcode == 0x18);