| David Brazdil | 0f672f6 | 2019-12-10 10:32:29 +0000 | [diff] [blame^] | 1 | /* SPDX-License-Identifier: GPL-2.0-only */ |
| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 2 | |
| 3 | #include <linux/linkage.h> |
| 4 | #include <asm/export.h> |
| 5 | |
| 6 | .text |
| 7 | |
| 8 | /* |
| 9 | * Inputs: |
| 10 | * %esi : memory location to compare |
| 11 | * %eax : low 32 bits of old value |
| 12 | * %edx : high 32 bits of old value |
| 13 | * %ebx : low 32 bits of new value |
| 14 | * %ecx : high 32 bits of new value |
| 15 | */ |
| 16 | ENTRY(cmpxchg8b_emu) |
| 17 | |
| 18 | # |
| 19 | # Emulate 'cmpxchg8b (%esi)' on UP except we don't |
| 20 | # set the whole ZF thing (caller will just compare |
| 21 | # eax:edx with the expected value) |
| 22 | # |
| 23 | pushfl |
| 24 | cli |
| 25 | |
| 26 | cmpl (%esi), %eax |
| 27 | jne .Lnot_same |
| 28 | cmpl 4(%esi), %edx |
| 29 | jne .Lhalf_same |
| 30 | |
| 31 | movl %ebx, (%esi) |
| 32 | movl %ecx, 4(%esi) |
| 33 | |
| 34 | popfl |
| 35 | ret |
| 36 | |
| 37 | .Lnot_same: |
| 38 | movl (%esi), %eax |
| 39 | .Lhalf_same: |
| 40 | movl 4(%esi), %edx |
| 41 | |
| 42 | popfl |
| 43 | ret |
| 44 | |
| 45 | ENDPROC(cmpxchg8b_emu) |
| 46 | EXPORT_SYMBOL(cmpxchg8b_emu) |