| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * __put_user functions. |
| * |
| * (C) Copyright 2005 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. |
| */ |
| #include <linux/linkage.h> |
| #include <asm/thread_info.h> |
| #include <asm/errno.h> |
| #include <asm/asm.h> |
| #include <asm/smap.h> |
| #include <asm/export.h> |
| |
| |
| /* |
| * __put_user_X |
| * |
| * Inputs: %eax[:%edx] contains the data |
| * %ecx contains the address |
| * |
| * Outputs: %eax is error code (0 or -EFAULT) |
| * |
| * These functions should not modify any other registers, |
| * as they get called from within inline assembly. |
| */ |
| |
| #define ENTER mov PER_CPU_VAR(current_task), %_ASM_BX |
| #define EXIT ASM_CLAC ; \ |
| ret |
| |
| .text |
| ENTRY(__put_user_1) |
| ENTER |
| cmp TASK_addr_limit(%_ASM_BX),%_ASM_CX |
| jae bad_put_user |
| ASM_STAC |
| 1: movb %al,(%_ASM_CX) |
| xor %eax,%eax |
| EXIT |
| ENDPROC(__put_user_1) |
| EXPORT_SYMBOL(__put_user_1) |
| |
| ENTRY(__put_user_2) |
| ENTER |
| mov TASK_addr_limit(%_ASM_BX),%_ASM_BX |
| sub $1,%_ASM_BX |
| cmp %_ASM_BX,%_ASM_CX |
| jae bad_put_user |
| ASM_STAC |
| 2: movw %ax,(%_ASM_CX) |
| xor %eax,%eax |
| EXIT |
| ENDPROC(__put_user_2) |
| EXPORT_SYMBOL(__put_user_2) |
| |
| ENTRY(__put_user_4) |
| ENTER |
| mov TASK_addr_limit(%_ASM_BX),%_ASM_BX |
| sub $3,%_ASM_BX |
| cmp %_ASM_BX,%_ASM_CX |
| jae bad_put_user |
| ASM_STAC |
| 3: movl %eax,(%_ASM_CX) |
| xor %eax,%eax |
| EXIT |
| ENDPROC(__put_user_4) |
| EXPORT_SYMBOL(__put_user_4) |
| |
| ENTRY(__put_user_8) |
| ENTER |
| mov TASK_addr_limit(%_ASM_BX),%_ASM_BX |
| sub $7,%_ASM_BX |
| cmp %_ASM_BX,%_ASM_CX |
| jae bad_put_user |
| ASM_STAC |
| 4: mov %_ASM_AX,(%_ASM_CX) |
| #ifdef CONFIG_X86_32 |
| 5: movl %edx,4(%_ASM_CX) |
| #endif |
| xor %eax,%eax |
| EXIT |
| ENDPROC(__put_user_8) |
| EXPORT_SYMBOL(__put_user_8) |
| |
| bad_put_user: |
| movl $-EFAULT,%eax |
| EXIT |
| END(bad_put_user) |
| |
| _ASM_EXTABLE(1b,bad_put_user) |
| _ASM_EXTABLE(2b,bad_put_user) |
| _ASM_EXTABLE(3b,bad_put_user) |
| _ASM_EXTABLE(4b,bad_put_user) |
| #ifdef CONFIG_X86_32 |
| _ASM_EXTABLE(5b,bad_put_user) |
| #endif |