From 3218357c94af92478ef39163163a81e654385320 Mon Sep 17 00:00:00 2001 From: Ralf Baechle Date: Fri, 10 Feb 2006 01:31:24 +0000 Subject: [PATCH] [MIPS] More uaccess.h fixes with gcc >= 4.0.1. From Richard Sandiford : This patch caused a miscompilation of the restore_gp_regs() block in restore_sigcontext(). This was in a 32-bit kernel compiled with GCC CVS head. restore_gp_regs() copies 64-bit user fields into 32-bit variables, and in this combination, the new __get_user_asm_ll32() clobbers too many registers. It says: /* * Get a long long 64 using 32 bit registers. */ { \ __asm__ __volatile__( \ "1: lw %1, (%3) \n" \ "2: lw %D1, 4(%3) \n" \ " move %0, $0 \n" \ "3: .section .fixup,\"ax\" \n" \ "4: li %0, %4 \n" \ " move %1, $0 \n" \ " move %D1, $0 \n" \ " j 3b \n" \ " .previous \n" \ " .section __ex_table,\"a\" \n" \ " " __UA_ADDR " 1b, 4b \n" \ " " __UA_ADDR " 2b, 4b \n" \ " .previous \n" \ : "=r" (__gu_err), "=&r" (val) \ : "0" (0), "r" (addr), "i" (-EFAULT)); \ } and this requires val (%1) to be a 64-bit value. In the case I saw, gcc was using $3 for the 32-bit val, and wasn't expecting $4 to be clobbered. Signed-off-by: Ralf Baechle --- include/asm-mips/uaccess.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/include/asm-mips/uaccess.h b/include/asm-mips/uaccess.h index 91d813a378..7a553e9d44 100644 --- a/include/asm-mips/uaccess.h +++ b/include/asm-mips/uaccess.h @@ -266,6 +266,8 @@ do { \ */ #define __get_user_asm_ll32(val, addr) \ { \ + unsigned long long __gu_tmp; \ + \ __asm__ __volatile__( \ "1: lw %1, (%3) \n" \ "2: lw %D1, 4(%3) \n" \ @@ -280,8 +282,9 @@ do { \ " " __UA_ADDR " 1b, 4b \n" \ " " __UA_ADDR " 2b, 4b \n" \ " .previous \n" \ - : "=r" (__gu_err), "=&r" (val) \ + : "=r" (__gu_err), "=&r" (__gu_tmp) \ : "0" (0), "r" (addr), "i" (-EFAULT)); \ + (val) = __gu_tmp; \ } /* -- 2.39.5