On Wed, Sep 01, 2004 at 09:51:16AM +0100, Richard Sandiford wrote:
> The latter. gcc is putting the empty asm:
>
> __asm__ ("":"=r" (__gu_val));
>
> into the delay slot of the call.
The purpose of this was to avoid a warning about __gu_val possibly being
used uninitialized without inflating the code. I've got a better solution
that'll actually shrinks the code size of my defconfig build by 5448
bytes. Untested patch below.
Ralf
Index: include/asm-mips/uaccess.h
===================================================================
RCS file: /home/cvs/linux/include/asm-mips/uaccess.h,v
retrieving revision 1.35
diff -u -r1.35 uaccess.h
--- include/asm-mips/uaccess.h 19 Sep 2004 12:30:20 -0000 1.35
+++ include/asm-mips/uaccess.h 20 Sep 2004 12:33:27 -0000
@@ -225,88 +225,86 @@
* for 32 bit mode and old iron.
*/
#ifdef __mips64
-#define __GET_USER_DW __get_user_asm("ld")
+#define __GET_USER_DW(__gu_err) __get_user_asm("ld", __gu_err)
#else
-#define __GET_USER_DW __get_user_asm_ll32
+#define __GET_USER_DW(__gu_err) __get_user_asm_ll32(__gu_err)
#endif
-#define __get_user_nocheck(x,ptr,size) \
-({ \
- long __gu_err; \
- __typeof(*(ptr)) __gu_val; \
- long __gu_addr; \
- might_sleep(); \
- __asm__("":"=r" (__gu_val)); \
- __gu_addr = (long) (ptr); \
- __asm__("":"=r" (__gu_err)); \
- switch (size) { \
- case 1: __get_user_asm("lb"); break; \
- case 2: __get_user_asm("lh"); break; \
- case 4: __get_user_asm("lw"); break; \
- case 8: __GET_USER_DW; break; \
- default: __get_user_unknown(); break; \
- } x = (__typeof__(*(ptr))) __gu_val; __gu_err; \
+#define __get_user_nocheck(x,ptr,size) \
+({ \
+ long __gu_err = 0; \
+ __typeof(*(ptr)) __gu_val = 0; \
+ long __gu_addr; \
+ might_sleep(); \
+ __gu_addr = (long) (ptr); \
+ switch (size) { \
+ case 1: __get_user_asm("lb", __gu_err); break; \
+ case 2: __get_user_asm("lh", __gu_err); break; \
+ case 4: __get_user_asm("lw", __gu_err); break; \
+ case 8: __GET_USER_DW(__gu_err); break; \
+ default: __get_user_unknown(); break; \
+ } \
+ x = (__typeof__(*(ptr))) __gu_val; \
+ __gu_err; \
})
#define __get_user_check(x,ptr,size) \
({ \
- long __gu_err; \
- __typeof__(*(ptr)) __gu_val; \
+ long __gu_err = 0; \
+ __typeof__(*(ptr)) __gu_val = 0; \
long __gu_addr; \
might_sleep(); \
- __asm__("":"=r" (__gu_val)); \
__gu_addr = (long) (ptr); \
- __asm__("":"=r" (__gu_err)); \
if (access_ok(VERIFY_READ,__gu_addr,size)) { \
switch (size) { \
- case 1: __get_user_asm("lb"); break; \
- case 2: __get_user_asm("lh"); break; \
- case 4: __get_user_asm("lw"); break; \
- case 8: __GET_USER_DW; break; \
+ case 1: __get_user_asm("lb", __gu_err); break; \
+ case 2: __get_user_asm("lh", __gu_err); break; \
+ case 4: __get_user_asm("lw", __gu_err); break; \
+ case 8: __GET_USER_DW(__gu_err); break; \
default: __get_user_unknown(); break; \
} \
- } x = (__typeof__(*(ptr))) __gu_val; __gu_err; \
+ } \
+ x = (__typeof__(*(ptr))) __gu_val; \
+ __gu_err; \
})
-#define __get_user_asm(insn) \
+#define __get_user_asm(insn,__gu_err) \
({ \
__asm__ __volatile__( \
- "1:\t" insn "\t%1,%2\n\t" \
- "move\t%0,$0\n" \
- "2:\n\t" \
- ".section\t.fixup,\"ax\"\n" \
- "3:\tli\t%0,%3\n\t" \
- "move\t%1,$0\n\t" \
- "j\t2b\n\t" \
- ".previous\n\t" \
- ".section\t__ex_table,\"a\"\n\t" \
- __UA_ADDR "\t1b,3b\n\t" \
- ".previous" \
- :"=r" (__gu_err), "=r" (__gu_val) \
- :"o" (__m(__gu_addr)), "i" (-EFAULT)); \
+ "1: " insn " %1, %3 \n" \
+ "2: \n" \
+ " .section .fixup,\"ax\" \n" \
+ "3: li %0, %4 \n" \
+ " j 2b \n" \
+ " .previous \n" \
+ " .section __ex_table,\"a\" \n" \
+ " "__UA_ADDR "\t1b, 3b \n" \
+ " .previous \n" \
+ : "=r" (__gu_err), "=r" (__gu_val) \
+ : "0" (__gu_err), "o" (__m(__gu_addr)), "i" (-EFAULT)); \
})
/*
* Get a long long 64 using 32 bit registers.
*/
-#define __get_user_asm_ll32 \
+#define __get_user_asm_ll32(__gu_err) \
({ \
__asm__ __volatile__( \
- "1:\tlw\t%1,%2\n" \
- "2:\tlw\t%D1,%3\n\t" \
- "move\t%0,$0\n" \
- "3:\t.section\t.fixup,\"ax\"\n" \
- "4:\tli\t%0,%4\n\t" \
- "move\t%1,$0\n\t" \
- "move\t%D1,$0\n\t" \
- "j\t3b\n\t" \
- ".previous\n\t" \
- ".section\t__ex_table,\"a\"\n\t" \
- __UA_ADDR "\t1b,4b\n\t" \
- __UA_ADDR "\t2b,4b\n\t" \
- ".previous" \
- :"=r" (__gu_err), "=&r" (__gu_val) \
- :"o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)), \
+ "1: lw %1,%2 \n" \
+ "2: lw %D1,%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" (__gu_val) \
+ : "o" (__m(__gu_addr)), "o" (__m(__gu_addr + 4)), \
"i" (-EFAULT)); \
})
@@ -317,25 +315,24 @@
* for 32 bit mode and old iron.
*/
#ifdef __mips64
-#define __PUT_USER_DW __put_user_asm("sd")
+#define __PUT_USER_DW(__pu_val) __put_user_asm("sd", __pu_val)
#else
-#define __PUT_USER_DW __put_user_asm_ll32
+#define __PUT_USER_DW(__pu_val) __put_user_asm_ll32(__pu_val)
#endif
#define __put_user_nocheck(x,ptr,size) \
({ \
- long __pu_err; \
+ long __pu_err = 0; \
__typeof__(*(ptr)) __pu_val; \
long __pu_addr; \
might_sleep(); \
__pu_val = (x); \
__pu_addr = (long) (ptr); \
- __asm__("":"=r" (__pu_err)); \
switch (size) { \
- case 1: __put_user_asm("sb"); break; \
- case 2: __put_user_asm("sh"); break; \
- case 4: __put_user_asm("sw"); break; \
- case 8: __PUT_USER_DW; break; \
+ case 1: __put_user_asm("sb", __pu_val); break; \
+ case 2: __put_user_asm("sh", __pu_val); break; \
+ case 4: __put_user_asm("sw", __pu_val); break; \
+ case 8: __PUT_USER_DW(__pu_val); break; \
default: __put_user_unknown(); break; \
} \
__pu_err; \
@@ -343,57 +340,55 @@
#define __put_user_check(x,ptr,size) \
({ \
- long __pu_err; \
+ long __pu_err = 0; \
__typeof__(*(ptr)) __pu_val; \
long __pu_addr; \
might_sleep(); \
__pu_val = (x); \
__pu_addr = (long) (ptr); \
- __asm__("":"=r" (__pu_err)); \
if (access_ok(VERIFY_WRITE, __pu_addr, size)) { \
switch (size) { \
- case 1: __put_user_asm("sb"); break; \
- case 2: __put_user_asm("sh"); break; \
- case 4: __put_user_asm("sw"); break; \
- case 8: __PUT_USER_DW; break; \
+ case 1: __put_user_asm("sb", __pu_val); break; \
+ case 2: __put_user_asm("sh", __pu_val); break; \
+ case 4: __put_user_asm("sw", __pu_val); break; \
+ case 8: __PUT_USER_DW(__pu_val); break; \
default: __put_user_unknown(); break; \
} \
} \
__pu_err; \
})
-#define __put_user_asm(insn) \
+#define __put_user_asm(insn, __pu_val) \
({ \
__asm__ __volatile__( \
- "1:\t" insn "\t%z1, %2\t\t\t# __put_user_asm\n\t" \
- "move\t%0, $0\n" \
- "2:\n\t" \
- ".section\t.fixup,\"ax\"\n" \
- "3:\tli\t%0,%3\n\t" \
- "j\t2b\n\t" \
- ".previous\n\t" \
- ".section\t__ex_table,\"a\"\n\t" \
- __UA_ADDR "\t1b,3b\n\t" \
- ".previous" \
+ "1: " insn " %z1, %2 # __put_user_asm\n" \
+ "2: \n" \
+ " .section .fixup,\"ax\" \n" \
+ "3: li %0,%3 \n" \
+ " j 2b \n" \
+ " .previous \n" \
+ " .section __ex_table,\"a\" \n" \
+ " " __UA_ADDR " 1b, 3b \n" \
+ " .previous \n" \
:"=r" (__pu_err) \
:"Jr" (__pu_val), "o" (__m(__pu_addr)), "i" (-EFAULT)); \
})
-#define __put_user_asm_ll32 \
+#define __put_user_asm_ll32(__pu_val) \
({ \
__asm__ __volatile__( \
- "1:\tsw\t%1, %2\t\t\t# __put_user_asm_ll32\n\t" \
- "2:\tsw\t%D1, %3\n" \
- "move\t%0, $0\n" \
- "3:\n\t" \
- ".section\t.fixup,\"ax\"\n" \
- "4:\tli\t%0,%4\n\t" \
- "j\t3b\n\t" \
- ".previous\n\t" \
- ".section\t__ex_table,\"a\"\n\t" \
- __UA_ADDR "\t1b,4b\n\t" \
- __UA_ADDR "\t2b,4b\n\t" \
- ".previous" \
+ "1: sw %1, %2 # __put_user_asm_ll32 \n" \
+ "2: sw %D1, %3 \n" \
+ " move %0, $0 \n" \
+ "3: \n" \
+ " .section .fixup,\"ax\" \n" \
+ "4: li %0, %4 \n" \
+ " j 3b \n" \
+ " .previous \n" \
+ " .section __ex_table,\"a\" \n" \
+ " " __UA_ADDR " 1b, 4b \n" \
+ " " __UA_ADDR " 2b, 4b \n" \
+ " .previous" \
:"=r" (__pu_err) \
:"r" (__pu_val), "o" (__m(__pu_addr)), \
"o" (__m(__pu_addr + 4)), "i" (-EFAULT)); \
