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author | Peter Zijlstra <peterz@infradead.org> | 2021-11-10 13:01:12 +0300 |
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committer | Peter Zijlstra <peterz@infradead.org> | 2021-12-11 11:09:47 +0300 |
commit | 99641e094d6ccf547b3eba833aea9a34fdf5681e (patch) | |
tree | e527b5ba2d297cc372c6f8165c39d5a8767a37d0 /arch/x86/include/asm/uaccess.h | |
parent | 4c132d1d844a53fc4e4b5c34e36ef10d6124b783 (diff) | |
download | linux-99641e094d6ccf547b3eba833aea9a34fdf5681e.tar.xz |
x86/uaccess: Remove .fixup usage
For the !CC_AS_ASM_GOTO_OUTPUT (aka. the legacy codepath), remove the
.fixup usage by employing both EX_TYPE_EFAULT_REG and EX_FLAG_CLEAR.
Like was already done for X86_32's version of __get_user_asm_u64() use
the "a" register for output, specifically so we can use CLEAR_AX.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20211110101325.485154848@infradead.org
Diffstat (limited to 'arch/x86/include/asm/uaccess.h')
-rw-r--r-- | arch/x86/include/asm/uaccess.h | 39 |
1 files changed, 17 insertions, 22 deletions
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h index 33a68407def3..ac6233a15856 100644 --- a/arch/x86/include/asm/uaccess.h +++ b/arch/x86/include/asm/uaccess.h @@ -351,24 +351,22 @@ do { \ "1: movl %[lowbits],%%eax\n" \ "2: movl %[highbits],%%edx\n" \ "3:\n" \ - ".section .fixup,\"ax\"\n" \ - "4: mov %[efault],%[errout]\n" \ - " xorl %%eax,%%eax\n" \ - " xorl %%edx,%%edx\n" \ - " jmp 3b\n" \ - ".previous\n" \ - _ASM_EXTABLE_UA(1b, 4b) \ - _ASM_EXTABLE_UA(2b, 4b) \ + _ASM_EXTABLE_TYPE_REG(1b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ + _ASM_EXTABLE_TYPE_REG(2b, 3b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX_DX, \ + %[errout]) \ : [errout] "=r" (retval), \ [output] "=&A"(x) \ : [lowbits] "m" (__m(__ptr)), \ [highbits] "m" __m(((u32 __user *)(__ptr)) + 1), \ - [efault] "i" (-EFAULT), "0" (retval)); \ + "0" (retval)); \ }) #else #define __get_user_asm_u64(x, ptr, retval) \ - __get_user_asm(x, ptr, retval, "q", "=r") + __get_user_asm(x, ptr, retval, "q") #endif #define __get_user_size(x, ptr, size, retval) \ @@ -379,14 +377,14 @@ do { \ __chk_user_ptr(ptr); \ switch (size) { \ case 1: \ - __get_user_asm(x_u8__, ptr, retval, "b", "=q"); \ + __get_user_asm(x_u8__, ptr, retval, "b"); \ (x) = x_u8__; \ break; \ case 2: \ - __get_user_asm(x, ptr, retval, "w", "=r"); \ + __get_user_asm(x, ptr, retval, "w"); \ break; \ case 4: \ - __get_user_asm(x, ptr, retval, "l", "=r"); \ + __get_user_asm(x, ptr, retval, "l"); \ break; \ case 8: \ __get_user_asm_u64(x, ptr, retval); \ @@ -396,20 +394,17 @@ do { \ } \ } while (0) -#define __get_user_asm(x, addr, err, itype, ltype) \ +#define __get_user_asm(x, addr, err, itype) \ asm volatile("\n" \ "1: mov"itype" %[umem],%[output]\n" \ "2:\n" \ - ".section .fixup,\"ax\"\n" \ - "3: mov %[efault],%[errout]\n" \ - " xorl %k[output],%k[output]\n" \ - " jmp 2b\n" \ - ".previous\n" \ - _ASM_EXTABLE_UA(1b, 3b) \ + _ASM_EXTABLE_TYPE_REG(1b, 2b, EX_TYPE_EFAULT_REG | \ + EX_FLAG_CLEAR_AX, \ + %[errout]) \ : [errout] "=r" (err), \ - [output] ltype(x) \ + [output] "=a" (x) \ : [umem] "m" (__m(addr)), \ - [efault] "i" (-EFAULT), "0" (err)) + "0" (err)) #endif // CONFIG_CC_HAS_ASM_GOTO_OUTPUT |