From bf0e12c753ee71fa9fcb1210e5b961ba1df7981f Mon Sep 17 00:00:00 2001 From: Michal Simek Date: Mon, 15 Oct 2012 11:49:22 +0200 Subject: microblaze: uaccess.h: Fix timerfd syscall __pu_val must be volatile to ensure that the value is not lost. It was causing the problem with timerfd syscall where using inline asm at the end of function call doesn't save u64 bit value to the stack. In comparison both cases you can find out this fragment where you can see the first part which is saved u64 value to stack and then using it in __put_user_asm_8 macro. Origin broken implementation misses the first two swi instructions. swi r22, r1, 28 /* missing without volatile */ swi r23, r1, 32 ... addik r4, r1, 28 lwi r3, r4, 0 swi r3, r25, 0 lwi r3, r4, 4 swi r3, r25, 4 addk r3, r0, r0 NOTE: Moving __put_val initialization after declaration has not impact on this bug. It is just coding style issue. Signed-off-by: Michal Simek --- arch/microblaze/include/asm/uaccess.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'arch/microblaze') diff --git a/arch/microblaze/include/asm/uaccess.h b/arch/microblaze/include/asm/uaccess.h index ef25f7538d4a..927540d3cb7d 100644 --- a/arch/microblaze/include/asm/uaccess.h +++ b/arch/microblaze/include/asm/uaccess.h @@ -298,11 +298,10 @@ extern long __user_bad(void); #define __put_user_check(x, ptr, size) \ ({ \ - typeof(*(ptr)) __pu_val; \ + typeof(*(ptr)) volatile __pu_val = x; \ typeof(*(ptr)) __user *__pu_addr = (ptr); \ int __pu_err = 0; \ \ - __pu_val = (x); \ if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \ switch (size) { \ case 1: \ -- cgit v1.2.1