| /* SPDX-License-Identifier: GPL-2.0 */ |
| /* |
| * Add-on to transform csum_partial_copy_nocheck in checksumcopy.S into |
| * csum_partial_copy_from_user by adding exception records. |
| * |
| * Copyright (C) 2001 Axis Communications AB. |
| * |
| * Author: Hans-Peter Nilsson. |
| */ |
| |
| #include <asm/errno.h> |
| |
| /* Same function body, but a different name. If we just added exception |
| records to _csum_partial_copy_nocheck and made it generic, we wouldn't |
| know a user fault from a kernel fault and we would have overhead in |
| each kernel caller for the error-pointer argument. |
| |
| unsigned int csum_partial_copy_from_user |
| (const char *src, char *dst, int len, unsigned int sum, int *errptr); |
| |
| Note that the errptr argument is only set if we encounter an error. |
| It is conveniently located on the stack, so the normal function body |
| does not have to handle it. */ |
| |
| #define csum_partial_copy_nocheck csum_partial_copy_from_user |
| |
| /* There are local labels numbered 1, 2 and 3 present to mark the |
| different from-user accesses. */ |
| #include "checksumcopy.S" |
| |
| .section .fixup,"ax" |
| |
| ;; Here from the movem loop; restore stack. |
| 4: |
| movem [$sp+],$r8 |
| ;; r12 is already decremented. Add back chunk_size-2. |
| addq 40-2,$r12 |
| |
| ;; Here from the word loop; r12 is off by 2; add it back. |
| 5: |
| addq 2,$r12 |
| |
| ;; Here from a failing single byte. |
| 6: |
| |
| ;; Signal in *errptr that we had a failing access. |
| moveq -EFAULT,$r9 |
| move.d $r9,[[$sp]] |
| |
| ;; Clear the rest of the destination area using memset. Preserve the |
| ;; checksum for the readable bytes. |
| push $srp |
| push $r13 |
| move.d $r11,$r10 |
| clear.d $r11 |
| jsr memset |
| pop $r10 |
| jump [$sp+] |
| |
| .previous |
| .section __ex_table,"a" |
| .dword 1b,4b |
| .dword 2b,5b |
| .dword 3b,6b |
| .previous |
