linux_dsm_epyc7002/arch/x86/lib/getuser.S
Josh Poimboeuf 82e844a653 x86/uaccess: Remove redundant CLACs in getuser/putuser error paths
The same getuser/putuser error paths are used regardless of whether AC
is set.  In non-exception failure cases, this results in an unnecessary
CLAC.

Fixes the following warnings:

  arch/x86/lib/getuser.o: warning: objtool: .altinstr_replacement+0x18: redundant UACCESS disable
  arch/x86/lib/putuser.o: warning: objtool: .altinstr_replacement+0x18: redundant UACCESS disable

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/bc14ded2755ae75bd9010c446079e113dbddb74b.1563413318.git.jpoimboe@redhat.com
2019-07-18 21:01:06 +02:00

144 lines
3.0 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/*
* __get_user functions.
*
* (C) Copyright 1998 Linus Torvalds
* (C) Copyright 2005 Andi Kleen
* (C) Copyright 2008 Glauber Costa
*
* These functions have a non-standard call interface
* to make them more efficient, especially as they
* return an error value in addition to the "real"
* return value.
*/
/*
* __get_user_X
*
* Inputs: %[r|e]ax contains the address.
*
* Outputs: %[r|e]ax is error code (0 or -EFAULT)
* %[r|e]dx contains zero-extended value
* %ecx contains the high half for 32-bit __get_user_8
*
*
* These functions should not modify any other registers,
* as they get called from within inline assembly.
*/
#include <linux/linkage.h>
#include <asm/page_types.h>
#include <asm/errno.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
#include <asm/asm.h>
#include <asm/smap.h>
#include <asm/export.h>
.text
ENTRY(__get_user_1)
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
and %_ASM_DX, %_ASM_AX
ASM_STAC
1: movzbl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__get_user_1)
EXPORT_SYMBOL(__get_user_1)
ENTRY(__get_user_2)
add $1,%_ASM_AX
jc bad_get_user
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
and %_ASM_DX, %_ASM_AX
ASM_STAC
2: movzwl -1(%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__get_user_2)
EXPORT_SYMBOL(__get_user_2)
ENTRY(__get_user_4)
add $3,%_ASM_AX
jc bad_get_user
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
and %_ASM_DX, %_ASM_AX
ASM_STAC
3: movl -3(%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__get_user_4)
EXPORT_SYMBOL(__get_user_4)
ENTRY(__get_user_8)
#ifdef CONFIG_X86_64
add $7,%_ASM_AX
jc bad_get_user
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user
sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
and %_ASM_DX, %_ASM_AX
ASM_STAC
4: movq -7(%_ASM_AX),%rdx
xor %eax,%eax
ASM_CLAC
ret
#else
add $7,%_ASM_AX
jc bad_get_user_8
mov PER_CPU_VAR(current_task), %_ASM_DX
cmp TASK_addr_limit(%_ASM_DX),%_ASM_AX
jae bad_get_user_8
sbb %_ASM_DX, %_ASM_DX /* array_index_mask_nospec() */
and %_ASM_DX, %_ASM_AX
ASM_STAC
4: movl -7(%_ASM_AX),%edx
5: movl -3(%_ASM_AX),%ecx
xor %eax,%eax
ASM_CLAC
ret
#endif
ENDPROC(__get_user_8)
EXPORT_SYMBOL(__get_user_8)
bad_get_user_clac:
ASM_CLAC
bad_get_user:
xor %edx,%edx
mov $(-EFAULT),%_ASM_AX
ret
#ifdef CONFIG_X86_32
bad_get_user_8_clac:
ASM_CLAC
bad_get_user_8:
xor %edx,%edx
xor %ecx,%ecx
mov $(-EFAULT),%_ASM_AX
ret
#endif
_ASM_EXTABLE_UA(1b, bad_get_user_clac)
_ASM_EXTABLE_UA(2b, bad_get_user_clac)
_ASM_EXTABLE_UA(3b, bad_get_user_clac)
#ifdef CONFIG_X86_64
_ASM_EXTABLE_UA(4b, bad_get_user_clac)
#else
_ASM_EXTABLE_UA(4b, bad_get_user_8_clac)
_ASM_EXTABLE_UA(5b, bad_get_user_8_clac)
#endif