1/* 2 * __put_user functions. 3 * 4 * (C) Copyright 1998 Linus Torvalds 5 * (C) Copyright 2005 Andi Kleen 6 * 7 * These functions have a non-standard call interface 8 * to make them more efficient, especially as they 9 * return an error value in addition to the "real" 10 * return value. 11 */ 12 13/* 14 * __put_user_X 15 * 16 * Inputs: %rcx contains the address 17 * %rdx contains new value 18 * 19 * Outputs: %rax is error code (0 or -EFAULT) 20 * 21 * %r8 is destroyed. 22 * 23 * These functions should not modify any other registers, 24 * as they get called from within inline assembly. 25 */ 26 27#include <linux/linkage.h> 28#include <asm/dwarf2.h> 29#include <asm/page.h> 30#include <asm/errno.h> 31#include <asm/asm-offsets.h> 32#include <asm/thread_info.h> 33 34 .text 35ENTRY(__put_user_1) 36 CFI_STARTPROC 37 GET_THREAD_INFO(%r8) 38 cmpq threadinfo_addr_limit(%r8),%rcx 39 jae bad_put_user 401: movb %dl,(%rcx) 41 xorl %eax,%eax 42 ret 43 CFI_ENDPROC 44ENDPROC(__put_user_1) 45 46ENTRY(__put_user_2) 47 CFI_STARTPROC 48 GET_THREAD_INFO(%r8) 49 addq $1,%rcx 50 jc 20f 51 cmpq threadinfo_addr_limit(%r8),%rcx 52 jae 20f 53 decq %rcx 542: movw %dx,(%rcx) 55 xorl %eax,%eax 56 ret 5720: decq %rcx 58 jmp bad_put_user 59 CFI_ENDPROC 60ENDPROC(__put_user_2) 61 62ENTRY(__put_user_4) 63 CFI_STARTPROC 64 GET_THREAD_INFO(%r8) 65 addq $3,%rcx 66 jc 30f 67 cmpq threadinfo_addr_limit(%r8),%rcx 68 jae 30f 69 subq $3,%rcx 703: movl %edx,(%rcx) 71 xorl %eax,%eax 72 ret 7330: subq $3,%rcx 74 jmp bad_put_user 75 CFI_ENDPROC 76ENDPROC(__put_user_4) 77 78ENTRY(__put_user_8) 79 CFI_STARTPROC 80 GET_THREAD_INFO(%r8) 81 addq $7,%rcx 82 jc 40f 83 cmpq threadinfo_addr_limit(%r8),%rcx 84 jae 40f 85 subq $7,%rcx 864: movq %rdx,(%rcx) 87 xorl %eax,%eax 88 ret 8940: subq $7,%rcx 90 jmp bad_put_user 91 CFI_ENDPROC 92ENDPROC(__put_user_8) 93 94bad_put_user: 95 CFI_STARTPROC 96 movq $(-EFAULT),%rax 97 ret 98 CFI_ENDPROC 99END(bad_put_user) 100 101.section __ex_table,"a" 102 .quad 1b,bad_put_user 103 .quad 2b,bad_put_user 104 .quad 3b,bad_put_user 105 .quad 4b,bad_put_user 106.previous 107