1/*
  2 * __put_user functions.
  3 *
  4 * (C) Copyright 2005 Linus Torvalds
  5 * (C) Copyright 2005 Andi Kleen
  6 * (C) Copyright 2008 Glauber Costa
  7 *
  8 * These functions have a non-standard call interface
  9 * to make them more efficient, especially as they
 10 * return an error value in addition to the "real"
 11 * return value.
 12 */
 13#include <linux/linkage.h>
 14#include <asm/dwarf2.h>
 15#include <asm/thread_info.h>
 16#include <asm/errno.h>
 17#include <asm/asm.h>
 18#include <asm/smap.h>
 19
 20
 21/*
 22 * __put_user_X
 23 *
 24 * Inputs:	%eax[:%edx] contains the data
 25 *		%ecx contains the address
 26 *
 27 * Outputs:	%eax is error code (0 or -EFAULT)
 28 *
 29 * These functions should not modify any other registers,
 30 * as they get called from within inline assembly.
 31 */
 32
 33#define ENTER	CFI_STARTPROC ; \
 34		GET_THREAD_INFO(%_ASM_BX)
 35#define EXIT	ASM_CLAC ;	\
 36		ret ;		\
 37		CFI_ENDPROC
 38
 39.text
 40ENTRY(__put_user_1)
 41	ENTER
 42	cmp TI_addr_limit(%_ASM_BX),%_ASM_CX
 43	jae bad_put_user
 44	ASM_STAC
 451:	movb %al,(%_ASM_CX)
 46	xor %eax,%eax
 47	EXIT
 48ENDPROC(__put_user_1)
 49
 50ENTRY(__put_user_2)
 51	ENTER
 52	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
 53	sub $1,%_ASM_BX
 54	cmp %_ASM_BX,%_ASM_CX
 55	jae bad_put_user
 56	ASM_STAC
 572:	movw %ax,(%_ASM_CX)
 58	xor %eax,%eax
 59	EXIT
 60ENDPROC(__put_user_2)
 61
 62ENTRY(__put_user_4)
 63	ENTER
 64	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
 65	sub $3,%_ASM_BX
 66	cmp %_ASM_BX,%_ASM_CX
 67	jae bad_put_user
 68	ASM_STAC
 693:	movl %eax,(%_ASM_CX)
 70	xor %eax,%eax
 71	EXIT
 72ENDPROC(__put_user_4)
 73
 74ENTRY(__put_user_8)
 75	ENTER
 76	mov TI_addr_limit(%_ASM_BX),%_ASM_BX
 77	sub $7,%_ASM_BX
 78	cmp %_ASM_BX,%_ASM_CX
 79	jae bad_put_user
 80	ASM_STAC
 814:	mov %_ASM_AX,(%_ASM_CX)
 82#ifdef CONFIG_X86_32
 835:	movl %edx,4(%_ASM_CX)
 84#endif
 85	xor %eax,%eax
 86	EXIT
 87ENDPROC(__put_user_8)
 88
 89bad_put_user:
 90	CFI_STARTPROC
 91	movl $-EFAULT,%eax
 92	EXIT
 93END(bad_put_user)
 94
 95	_ASM_EXTABLE(1b,bad_put_user)
 96	_ASM_EXTABLE(2b,bad_put_user)
 97	_ASM_EXTABLE(3b,bad_put_user)
 98	_ASM_EXTABLE(4b,bad_put_user)
 99#ifdef CONFIG_X86_32
100	_ASM_EXTABLE(5b,bad_put_user)
101#endif