| /* |
| * __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. |
| * The register is modified, but all changes are undone |
| * before returning because the C code doesn't know about it. |
| * |
| * Outputs: %[r|e]ax is error code (0 or -EFAULT) |
| * %[r|e]dx contains zero-extended value |
| * |
| * |
| * These functions should not modify any other registers, |
| * as they get called from within inline assembly. |
| */ |
| |
| #include <linux/linkage.h> |
| #include <asm/dwarf2.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) |
| CFI_STARTPROC |
| GET_THREAD_INFO(%_ASM_DX) |
| cmp TI_addr_limit(%_ASM_DX),%_ASM_AX |
| jae bad_get_user |
| ASM_STAC |
| 1: movzb (%_ASM_AX),%edx |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| CFI_ENDPROC |
| ENDPROC(__get_user_1) |
| |
| ENTRY(__get_user_2) |
| CFI_STARTPROC |
| add $1,%_ASM_AX |
| jc bad_get_user |
| GET_THREAD_INFO(%_ASM_DX) |
| cmp TI_addr_limit(%_ASM_DX),%_ASM_AX |
| jae bad_get_user |
| ASM_STAC |
| 2: movzwl -1(%_ASM_AX),%edx |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| CFI_ENDPROC |
| ENDPROC(__get_user_2) |
| |
| ENTRY(__get_user_4) |
| CFI_STARTPROC |
| add $3,%_ASM_AX |
| jc bad_get_user |
| GET_THREAD_INFO(%_ASM_DX) |
| cmp TI_addr_limit(%_ASM_DX),%_ASM_AX |
| jae bad_get_user |
| ASM_STAC |
| 3: mov -3(%_ASM_AX),%edx |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| CFI_ENDPROC |
| ENDPROC(__get_user_4) |
| |
| #ifdef CONFIG_X86_64 |
| ENTRY(__get_user_8) |
| CFI_STARTPROC |
| add $7,%_ASM_AX |
| jc bad_get_user |
| GET_THREAD_INFO(%_ASM_DX) |
| cmp TI_addr_limit(%_ASM_DX),%_ASM_AX |
| jae bad_get_user |
| ASM_STAC |
| 4: movq -7(%_ASM_AX),%_ASM_DX |
| xor %eax,%eax |
| ASM_CLAC |
| ret |
| CFI_ENDPROC |
| ENDPROC(__get_user_8) |
| #endif |
| |
| bad_get_user: |
| CFI_STARTPROC |
| xor %edx,%edx |
| mov $(-EFAULT),%_ASM_AX |
| ASM_CLAC |
| ret |
| CFI_ENDPROC |
| END(bad_get_user) |
| |
| _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) |
| #endif |
