'asm goto output' generates noticeably better code since we don't need
to test the error etc, the exception just jumps to the error handling
directly.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
---
arch/riscv/include/asm/uaccess.h | 88 +++++++++++++++++++++++---------
1 file changed, 63 insertions(+), 25 deletions(-)
diff --git a/arch/riscv/include/asm/uaccess.h b/arch/riscv/include/asm/uaccess.h
index d8c44705b61d..d9c32b4f7d13 100644
--- a/arch/riscv/include/asm/uaccess.h
+++ b/arch/riscv/include/asm/uaccess.h
@@ -63,27 +63,54 @@
* call.
*/
-#define __get_user_asm(insn, x, ptr, err) \
+#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
+#define __get_user_asm(insn, x, ptr, label) \
+ asm_goto_output( \
+ "1:\n" \
+ " " insn " %0, %1\n" \
+ _ASM_EXTABLE_UACCESS_ERR(1b, %l2, %0) \
+ : "=&r" (x) \
+ : "m" (*(ptr)) : : label)
+#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
+#define __get_user_asm(insn, x, ptr, label) \
do { \
- __typeof__(x) __x; \
+ long __gua_err = 0; \
__asm__ __volatile__ ( \
"1:\n" \
" " insn " %1, %2\n" \
"2:\n" \
_ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 2b, %0, %1) \
- : "+r" (err), "=&r" (__x) \
+ : "+r" (__gua_err), "=&r" (x) \
: "m" (*(ptr))); \
- (x) = __x; \
+ if (__gua_err) \
+ goto label; \
} while (0)
+#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
#ifdef CONFIG_64BIT
-#define __get_user_8(x, ptr, err) \
- __get_user_asm("ld", x, ptr, err)
+#define __get_user_8(x, ptr, label) \
+ __get_user_asm("ld", x, ptr, label)
#else /* !CONFIG_64BIT */
-#define __get_user_8(x, ptr, err) \
+
+#ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
+#define __get_user_8(x, ptr, label) \
+ asm_goto_output( \
+ "1:\n" \
+ " lw %0, %2\n" \
+ "2:\n" \
+ " lw %1, %3\n" \
+ _ASM_EXTABLE_UACCESS_ERR(1b, %l4, %0) \
+ _ASM_EXTABLE_UACCESS_ERR(2b, %l4, %0) \
+ : "=&r" (__lo), "=r" (__hi) \
+ : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]) \
+ : : label)
+
+#else /* !CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
+#define __get_user_8(x, ptr, label) \
do { \
u32 __user *__ptr = (u32 __user *)(ptr); \
u32 __lo, __hi; \
+ long __gu8_err = 0; \
__asm__ __volatile__ ( \
"1:\n" \
" lw %1, %3\n" \
@@ -92,35 +119,51 @@ do { \
"3:\n" \
_ASM_EXTABLE_UACCESS_ERR_ZERO(1b, 3b, %0, %1) \
_ASM_EXTABLE_UACCESS_ERR_ZERO(2b, 3b, %0, %1) \
- : "+r" (err), "=&r" (__lo), "=r" (__hi) \
+ : "+r" (__gu8_err), "=&r" (__lo), "=r" (__hi) \
: "m" (__ptr[__LSW]), "m" (__ptr[__MSW])); \
- if (err) \
+ if (__gu8_err) { \
__hi = 0; \
+ goto label; \
+ } \
(x) = (__typeof__(x))((__typeof__((x)-(x)))( \
(((u64)__hi << 32) | __lo))); \
} while (0)
+#endif /* CONFIG_CC_HAS_ASM_GOTO_OUTPUT */
+
#endif /* CONFIG_64BIT */
-#define __get_user_nocheck(x, __gu_ptr, __gu_err) \
+#define __get_user_nocheck(x, __gu_ptr, label) \
do { \
switch (sizeof(*__gu_ptr)) { \
case 1: \
- __get_user_asm("lb", (x), __gu_ptr, __gu_err); \
+ __get_user_asm("lb", (x), __gu_ptr, label); \
break; \
case 2: \
- __get_user_asm("lh", (x), __gu_ptr, __gu_err); \
+ __get_user_asm("lh", (x), __gu_ptr, label); \
break; \
case 4: \
- __get_user_asm("lw", (x), __gu_ptr, __gu_err); \
+ __get_user_asm("lw", (x), __gu_ptr, label); \
break; \
case 8: \
- __get_user_8((x), __gu_ptr, __gu_err); \
+ __get_user_8((x), __gu_ptr, label); \
break; \
default: \
BUILD_BUG(); \
} \
} while (0)
+#define __get_user_error(x, ptr, err) \
+do { \
+ __label__ __gu_failed; \
+ \
+ __get_user_nocheck(x, ptr, __gu_failed); \
+ err = 0; \
+ break; \
+__gu_failed: \
+ x = 0; \
+ err = -EFAULT; \
+} while (0)
+
/**
* __get_user: - Get a simple variable from user space, with less checking.
* @x: Variable to store result.
@@ -145,13 +188,16 @@ do { \
({ \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
long __gu_err = 0; \
+ __typeof__(x) __gu_val; \
\
__chk_user_ptr(__gu_ptr); \
\
__enable_user_access(); \
- __get_user_nocheck(x, __gu_ptr, __gu_err); \
+ __get_user_error(__gu_val, __gu_ptr, __gu_err); \
__disable_user_access(); \
\
+ (x) = __gu_val; \
+ \
__gu_err; \
})
@@ -336,13 +382,7 @@ unsigned long __must_check clear_user(void __user *to, unsigned long n)
}
#define __get_kernel_nofault(dst, src, type, err_label) \
-do { \
- long __kr_err = 0; \
- \
- __get_user_nocheck(*((type *)(dst)), (type *)(src), __kr_err); \
- if (unlikely(__kr_err)) \
- goto err_label; \
-} while (0)
+ __get_user_nocheck(*((type *)(dst)), (type *)(src), err_label);
#define __put_kernel_nofault(dst, src, type, err_label) \
__put_user_nocheck(*((type *)(src)), (type *)(dst), err_label);
@@ -364,11 +404,9 @@ static inline void user_access_restore(unsigned long enabled) { }
__put_user_nocheck(x, (ptr), label);
#define unsafe_get_user(x, ptr, label) do { \
- long __kr_err = 0; \
__inttype(*(ptr)) __gu_val; \
- __get_user_nocheck(__gu_val, (ptr), __kr_err); \
+ __get_user_nocheck(__gu_val, (ptr), label); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
- if (__kr_err) goto label; \
} while (0)
/*
--
2.43.0Hi Jisheng,
kernel test robot noticed the following build errors:
[auto build test ERROR on linus/master]
[also build test ERROR on v6.10-rc6]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Jisheng-Zhang/riscv-implement-user_access_begin-and-families/20240626-005352
base: linus/master
patch link: https://lore.kernel.org/r/20240625040500.1788-5-jszhang%40kernel.org
patch subject: [PATCH 4/4] riscv: uaccess: use 'asm goto output' for get_user
config: riscv-randconfig-r121-20240705 (https://download.01.org/0day-ci/archive/20240705/202407051159.ArkAPA6L-lkp@intel.com/config)
compiler: riscv32-linux-gcc (GCC) 13.2.0
reproduce: (https://download.01.org/0day-ci/archive/20240705/202407051159.ArkAPA6L-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202407051159.ArkAPA6L-lkp@intel.com/
All errors (new ones prefixed by >>):
In file included from include/linux/compiler_types.h:174,
from <command-line>:
net/rfkill/core.c: In function 'rfkill_fop_ioctl':
>> arch/riscv/include/asm/uaccess.h:104:26: error: '__lo' undeclared (first use in this function)
104 | : "=&r" (__lo), "=r" (__hi) \
| ^~~~
include/linux/compiler-gcc.h:84:32: note: in definition of macro 'asm_goto_output'
84 | do { asm volatile goto(x); asm (""); } while (0)
| ^
arch/riscv/include/asm/uaccess.h:148:17: note: in expansion of macro '__get_user_8'
148 | __get_user_8((x), __gu_ptr, label); \
| ^~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:159:9: note: in expansion of macro '__get_user_nocheck'
159 | __get_user_nocheck(x, ptr, __gu_failed); \
| ^~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:196:9: note: in expansion of macro '__get_user_error'
196 | __get_user_error(__gu_val, __gu_ptr, __gu_err); \
| ^~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:226:17: note: in expansion of macro '__get_user'
226 | __get_user((x), __p) : \
| ^~~~~~~~~~
net/rfkill/core.c:1373:21: note: in expansion of macro 'get_user'
1373 | if (get_user(size, (__u32 __user *)arg)) {
| ^~~~~~~~
arch/riscv/include/asm/uaccess.h:104:26: note: each undeclared identifier is reported only once for each function it appears in
104 | : "=&r" (__lo), "=r" (__hi) \
| ^~~~
include/linux/compiler-gcc.h:84:32: note: in definition of macro 'asm_goto_output'
84 | do { asm volatile goto(x); asm (""); } while (0)
| ^
arch/riscv/include/asm/uaccess.h:148:17: note: in expansion of macro '__get_user_8'
148 | __get_user_8((x), __gu_ptr, label); \
| ^~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:159:9: note: in expansion of macro '__get_user_nocheck'
159 | __get_user_nocheck(x, ptr, __gu_failed); \
| ^~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:196:9: note: in expansion of macro '__get_user_error'
196 | __get_user_error(__gu_val, __gu_ptr, __gu_err); \
| ^~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:226:17: note: in expansion of macro '__get_user'
226 | __get_user((x), __p) : \
| ^~~~~~~~~~
net/rfkill/core.c:1373:21: note: in expansion of macro 'get_user'
1373 | if (get_user(size, (__u32 __user *)arg)) {
| ^~~~~~~~
>> arch/riscv/include/asm/uaccess.h:104:39: error: '__hi' undeclared (first use in this function)
104 | : "=&r" (__lo), "=r" (__hi) \
| ^~~~
include/linux/compiler-gcc.h:84:32: note: in definition of macro 'asm_goto_output'
84 | do { asm volatile goto(x); asm (""); } while (0)
| ^
arch/riscv/include/asm/uaccess.h:148:17: note: in expansion of macro '__get_user_8'
148 | __get_user_8((x), __gu_ptr, label); \
| ^~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:159:9: note: in expansion of macro '__get_user_nocheck'
159 | __get_user_nocheck(x, ptr, __gu_failed); \
| ^~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:196:9: note: in expansion of macro '__get_user_error'
196 | __get_user_error(__gu_val, __gu_ptr, __gu_err); \
| ^~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:226:17: note: in expansion of macro '__get_user'
226 | __get_user((x), __p) : \
| ^~~~~~~~~~
net/rfkill/core.c:1373:21: note: in expansion of macro 'get_user'
1373 | if (get_user(size, (__u32 __user *)arg)) {
| ^~~~~~~~
>> arch/riscv/include/asm/uaccess.h:105:24: error: '__ptr' undeclared (first use in this function); did you mean '__p'?
105 | : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]) \
| ^~~~~
include/linux/compiler-gcc.h:84:32: note: in definition of macro 'asm_goto_output'
84 | do { asm volatile goto(x); asm (""); } while (0)
| ^
arch/riscv/include/asm/uaccess.h:148:17: note: in expansion of macro '__get_user_8'
148 | __get_user_8((x), __gu_ptr, label); \
| ^~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:159:9: note: in expansion of macro '__get_user_nocheck'
159 | __get_user_nocheck(x, ptr, __gu_failed); \
| ^~~~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:196:9: note: in expansion of macro '__get_user_error'
196 | __get_user_error(__gu_val, __gu_ptr, __gu_err); \
| ^~~~~~~~~~~~~~~~
arch/riscv/include/asm/uaccess.h:226:17: note: in expansion of macro '__get_user'
226 | __get_user((x), __p) : \
| ^~~~~~~~~~
net/rfkill/core.c:1373:21: note: in expansion of macro 'get_user'
1373 | if (get_user(size, (__u32 __user *)arg)) {
| ^~~~~~~~
vim +/__lo +104 arch/riscv/include/asm/uaccess.h
94
95 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT
96 #define __get_user_8(x, ptr, label) \
97 asm_goto_output( \
98 "1:\n" \
99 " lw %0, %2\n" \
100 "2:\n" \
101 " lw %1, %3\n" \
102 _ASM_EXTABLE_UACCESS_ERR(1b, %l4, %0) \
103 _ASM_EXTABLE_UACCESS_ERR(2b, %l4, %0) \
> 104 : "=&r" (__lo), "=r" (__hi) \
> 105 : "m" (__ptr[__LSW]), "m" (__ptr[__MSW]) \
106 : : label)
107
--
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