projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 51533b61 MS |
2 | /* |
| 3 | * Add-on to transform csum_partial_copy_nocheck in checksumcopy.S into | |
| 4 | * csum_partial_copy_from_user by adding exception records. | |
| 5 | * | |
| 6 | * Copyright (C) 2001, 2003 Axis Communications AB. | |
| 7 | * | |
| 8 | * Author: Hans-Peter Nilsson. | |
| 9 | */ | |
| 10 | ||
| 11 | #include <asm/errno.h> | |
| 12 | ||
| 13 | /* Same function body, but a different name. If we just added exception | |
| 14 | records to _csum_partial_copy_nocheck and made it generic, we wouldn't | |
| 15 | know a user fault from a kernel fault and we would have overhead in | |
| 16 | each kernel caller for the error-pointer argument. | |
| 17 | ||
| 18 | unsigned int csum_partial_copy_from_user | |
| 19 | (const char *src, char *dst, int len, unsigned int sum, int *errptr); | |
| 20 | ||
| 21 | Note that the errptr argument is only set if we encounter an error. | |
| 22 | It is conveniently located on the stack, so the normal function body | |
| 23 | does not have to handle it. */ | |
| 24 | ||
| 25 | #define csum_partial_copy_nocheck csum_partial_copy_from_user | |
| 26 | ||
| 27 | /* There are local labels numbered 1, 2 and 3 present to mark the | |
| 28 | different from-user accesses. */ | |
| 29 | #include "checksumcopy.S" | |
| 30 | ||
| 31 | .section .fixup,"ax" | |
| 32 | ||
| 33 | ;; Here from the movem loop; restore stack. | |
| 34 | 4: | |
| 35 | movem [$sp+],$r8 | |
| 36 | ;; r12 is already decremented. Add back chunk_size-2. | |
| 37 | addq 40-2,$r12 | |
| 38 | ||
| 39 | ;; Here from the word loop; r12 is off by 2; add it back. | |
| 40 | 5: | |
| 41 | addq 2,$r12 | |
| 42 | ||
| 43 | ;; Here from a failing single byte. | |
| 44 | 6: | |
| 45 | ||
| 46 | ;; Signal in *errptr that we had a failing access. | |
| 47 | move.d [$sp],$acr | |
| 48 | moveq -EFAULT,$r9 | |
| 49 | subq 4,$sp | |
| 50 | move.d $r9,[$acr] | |
| 51 | ||
| 52 | ;; Clear the rest of the destination area using memset. Preserve the | |
| 53 | ;; checksum for the readable bytes. | |
| 54 | move.d $r13,[$sp] | |
| 55 | subq 4,$sp | |
| 56 | move.d $r11,$r10 | |
| 57 | move $srp,[$sp] | |
| 58 | jsr memset | |
| 59 | clear.d $r11 | |
| 60 | ||
| 61 | move [$sp+],$srp | |
| 62 | ret | |
| 63 | move.d [$sp+],$r10 | |
| 64 | ||
| 65 | .previous | |
| 66 | .section __ex_table,"a" | |
| 67 | .dword 1b,4b | |
| 68 | .dword 2b,5b | |
| 69 | .dword 3b,6b | |
| 70 | .previous |