niansa-misc/linux
1
0
Fork 0
mirror of synced 2025-03-06 20:59:54 +01:00
Code Issues Projects Releases Packages Wiki Activity

x86/uaccess: Improve the 8-byte getuser() case

Browse source 
Streamline the 8-byte case and drop the special handling. Use a macro
which hides the exception handling.

No functional changes.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/r/CAHk-=whYb2L_atsRk9pBiFiVLGe5wNZLHhRinA69yu6FiKvDsw@mail.gmail.com
This commit is contained in:
Linus Torvalds 2024-06-19 14:54:23 +02:00 • committed by Borislav Petkov (AMD)
parent 6ba59ff422
commit 8a2462df15
1 changed files with 20 additions and 49 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

69
arch/x86/lib/getuser.S
View file

@ -44,21 +44,23 @@
or %rdx, %rax or %rdx, %rax
.else .else
cmp $TASK_SIZE_MAX-\size+1, %eax cmp $TASK_SIZE_MAX-\size+1, %eax
.if \size != 8
jae .Lbad_get_user jae .Lbad_get_user
.else
jae .Lbad_get_user_8
.endif
sbb %edx, %edx /* array_index_mask_nospec() */ sbb %edx, %edx /* array_index_mask_nospec() */
and %edx, %eax and %edx, %eax
.endif .endif
.endm .endm
.macro UACCESS op src dst
1: \op \src,\dst
_ASM_EXTABLE_UA(1b, __get_user_handle_exception)
.endm
.text .text
SYM_FUNC_START(__get_user_1) SYM_FUNC_START(__get_user_1)
check_range size=1 check_range size=1
ASM_STAC ASM_STAC
1: movzbl (%_ASM_AX),%edx UACCESS movzbl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -68,7 +70,7 @@ EXPORT_SYMBOL(__get_user_1)
SYM_FUNC_START(__get_user_2) SYM_FUNC_START(__get_user_2)
check_range size=2 check_range size=2
ASM_STAC ASM_STAC
2: movzwl (%_ASM_AX),%edx UACCESS movzwl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -78,7 +80,7 @@ EXPORT_SYMBOL(__get_user_2)
SYM_FUNC_START(__get_user_4) SYM_FUNC_START(__get_user_4)
check_range size=4 check_range size=4
ASM_STAC ASM_STAC
3: movl (%_ASM_AX),%edx UACCESS movl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -89,10 +91,11 @@ SYM_FUNC_START(__get_user_8)
check_range size=8 check_range size=8
ASM_STAC ASM_STAC
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
4: movq (%_ASM_AX),%rdx UACCESS movq (%_ASM_AX),%rdx
#else #else
4: movl (%_ASM_AX),%edx xor %ecx,%ecx
5: movl 4(%_ASM_AX),%ecx UACCESS movl (%_ASM_AX),%edx
UACCESS movl 4(%_ASM_AX),%ecx
#endif #endif
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
@ -104,7 +107,7 @@ EXPORT_SYMBOL(__get_user_8)
SYM_FUNC_START(__get_user_nocheck_1) SYM_FUNC_START(__get_user_nocheck_1)
ASM_STAC ASM_STAC
ASM_BARRIER_NOSPEC ASM_BARRIER_NOSPEC
6: movzbl (%_ASM_AX),%edx UACCESS movzbl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -114,7 +117,7 @@ EXPORT_SYMBOL(__get_user_nocheck_1)
SYM_FUNC_START(__get_user_nocheck_2) SYM_FUNC_START(__get_user_nocheck_2)
ASM_STAC ASM_STAC
ASM_BARRIER_NOSPEC ASM_BARRIER_NOSPEC
7: movzwl (%_ASM_AX),%edx UACCESS movzwl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -124,7 +127,7 @@ EXPORT_SYMBOL(__get_user_nocheck_2)
SYM_FUNC_START(__get_user_nocheck_4) SYM_FUNC_START(__get_user_nocheck_4)
ASM_STAC ASM_STAC
ASM_BARRIER_NOSPEC ASM_BARRIER_NOSPEC
8: movl (%_ASM_AX),%edx UACCESS movl (%_ASM_AX),%edx
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
RET RET
@ -135,10 +138,11 @@ SYM_FUNC_START(__get_user_nocheck_8)
ASM_STAC ASM_STAC
ASM_BARRIER_NOSPEC ASM_BARRIER_NOSPEC
#ifdef CONFIG_X86_64 #ifdef CONFIG_X86_64
9: movq (%_ASM_AX),%rdx UACCESS movq (%_ASM_AX),%rdx
#else #else
9: movl (%_ASM_AX),%edx xor %ecx,%ecx
10: movl 4(%_ASM_AX),%ecx UACCESS movl (%_ASM_AX),%edx
UACCESS movl 4(%_ASM_AX),%ecx
#endif #endif
xor %eax,%eax xor %eax,%eax
ASM_CLAC ASM_CLAC
@ -154,36 +158,3 @@ SYM_CODE_START_LOCAL(__get_user_handle_exception)
mov $(-EFAULT),%_ASM_AX mov $(-EFAULT),%_ASM_AX
RET RET
SYM_CODE_END(__get_user_handle_exception) SYM_CODE_END(__get_user_handle_exception)
#ifdef CONFIG_X86_32
SYM_CODE_START_LOCAL(__get_user_8_handle_exception)
ASM_CLAC
.Lbad_get_user_8:
xor %edx,%edx
xor %ecx,%ecx
mov $(-EFAULT),%_ASM_AX
RET
SYM_CODE_END(__get_user_8_handle_exception)
#endif
/* get_user */
_ASM_EXTABLE_UA(1b, __get_user_handle_exception)
_ASM_EXTABLE_UA(2b, __get_user_handle_exception)
_ASM_EXTABLE_UA(3b, __get_user_handle_exception)
#ifdef CONFIG_X86_64
_ASM_EXTABLE_UA(4b, __get_user_handle_exception)
#else
_ASM_EXTABLE_UA(4b, __get_user_8_handle_exception)
_ASM_EXTABLE_UA(5b, __get_user_8_handle_exception)
#endif
/* __get_user */
_ASM_EXTABLE_UA(6b, __get_user_handle_exception)
_ASM_EXTABLE_UA(7b, __get_user_handle_exception)
_ASM_EXTABLE_UA(8b, __get_user_handle_exception)
#ifdef CONFIG_X86_64
_ASM_EXTABLE_UA(9b, __get_user_handle_exception)
#else
_ASM_EXTABLE_UA(9b, __get_user_8_handle_exception)
_ASM_EXTABLE_UA(10b, __get_user_8_handle_exception)
#endif