linux/arch/x86/lib/getuser.S
Andy Lutomirski 13d4ea097d x86/uaccess: Move thread_info::addr_limit to thread_struct
struct thread_info is a legacy mess.  To prepare for its partial removal,
move thread_info::addr_limit out.

As an added benefit, this way is simpler.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/15bee834d09402b47ac86f2feccdf6529f9bc5b0.1468527351.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-07-15 10:26:30 +02:00

128 lines
2.4 KiB
ArmAsm

/*
* __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>
.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
ASM_STAC
1: movzbl (%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__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
ASM_STAC
2: movzwl -1(%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__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
ASM_STAC
3: movl -3(%_ASM_AX),%edx
xor %eax,%eax
ASM_CLAC
ret
ENDPROC(__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
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
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)
bad_get_user:
xor %edx,%edx
mov $(-EFAULT),%_ASM_AX
ASM_CLAC
ret
END(bad_get_user)
#ifdef CONFIG_X86_32
bad_get_user_8:
xor %edx,%edx
xor %ecx,%ecx
mov $(-EFAULT),%_ASM_AX
ASM_CLAC
ret
END(bad_get_user_8)
#endif
_ASM_EXTABLE(1b,bad_get_user)
_ASM_EXTABLE(2b,bad_get_user)
_ASM_EXTABLE(3b,bad_get_user)
#ifdef CONFIG_X86_64
_ASM_EXTABLE(4b,bad_get_user)
#else
_ASM_EXTABLE(4b,bad_get_user_8)
_ASM_EXTABLE(5b,bad_get_user_8)
#endif