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 102