diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 11:22:41 -0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-16 11:22:41 -0400 |
commit | 79d8a8f736151b12129984b1250fd708440e742c (patch) | |
tree | f67eebe2bafca8820955ee9f851985a41fb32e66 /arch/x86/lib | |
parent | bd2895eeade5f11f3e5906283c630bbdb4b57454 (diff) | |
parent | b9ec40af0e18fb7d02106be148036c2ea490fdf9 (diff) |
Merge branch 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu
* 'for-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu:
percpu, x86: Add arch-specific this_cpu_cmpxchg_double() support
percpu: Generic support for this_cpu_cmpxchg_double()
alpha: use L1_CACHE_BYTES for cacheline size in the linker script
percpu: align percpu readmostly subsection to cacheline
Fix up trivial conflict in arch/x86/kernel/vmlinux.lds.S due to the
percpu alignment having changed ("x86: Reduce back the alignment of the
per-CPU data section")
Diffstat (limited to 'arch/x86/lib')
-rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
-rw-r--r-- | arch/x86/lib/cmpxchg16b_emu.S | 59 |
2 files changed, 60 insertions, 0 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index e10cf070ede0..f2479f19ddde 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile | |||
@@ -42,4 +42,5 @@ else | |||
42 | lib-y += memmove_64.o memset_64.o | 42 | lib-y += memmove_64.o memset_64.o |
43 | lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o | 43 | lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o |
44 | lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o | 44 | lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o |
45 | lib-y += cmpxchg16b_emu.o | ||
45 | endif | 46 | endif |
diff --git a/arch/x86/lib/cmpxchg16b_emu.S b/arch/x86/lib/cmpxchg16b_emu.S new file mode 100644 index 000000000000..3e8b08a6de2b --- /dev/null +++ b/arch/x86/lib/cmpxchg16b_emu.S | |||
@@ -0,0 +1,59 @@ | |||
1 | /* | ||
2 | * This program is free software; you can redistribute it and/or | ||
3 | * modify it under the terms of the GNU General Public License | ||
4 | * as published by the Free Software Foundation; version 2 | ||
5 | * of the License. | ||
6 | * | ||
7 | */ | ||
8 | #include <linux/linkage.h> | ||
9 | #include <asm/alternative-asm.h> | ||
10 | #include <asm/frame.h> | ||
11 | #include <asm/dwarf2.h> | ||
12 | |||
13 | .text | ||
14 | |||
15 | /* | ||
16 | * Inputs: | ||
17 | * %rsi : memory location to compare | ||
18 | * %rax : low 64 bits of old value | ||
19 | * %rdx : high 64 bits of old value | ||
20 | * %rbx : low 64 bits of new value | ||
21 | * %rcx : high 64 bits of new value | ||
22 | * %al : Operation successful | ||
23 | */ | ||
24 | ENTRY(this_cpu_cmpxchg16b_emu) | ||
25 | CFI_STARTPROC | ||
26 | |||
27 | # | ||
28 | # Emulate 'cmpxchg16b %gs:(%rsi)' except we return the result in %al not | ||
29 | # via the ZF. Caller will access %al to get result. | ||
30 | # | ||
31 | # Note that this is only useful for a cpuops operation. Meaning that we | ||
32 | # do *not* have a fully atomic operation but just an operation that is | ||
33 | # *atomic* on a single cpu (as provided by the this_cpu_xx class of | ||
34 | # macros). | ||
35 | # | ||
36 | this_cpu_cmpxchg16b_emu: | ||
37 | pushf | ||
38 | cli | ||
39 | |||
40 | cmpq %gs:(%rsi), %rax | ||
41 | jne not_same | ||
42 | cmpq %gs:8(%rsi), %rdx | ||
43 | jne not_same | ||
44 | |||
45 | movq %rbx, %gs:(%rsi) | ||
46 | movq %rcx, %gs:8(%rsi) | ||
47 | |||
48 | popf | ||
49 | mov $1, %al | ||
50 | ret | ||
51 | |||
52 | not_same: | ||
53 | popf | ||
54 | xor %al,%al | ||
55 | ret | ||
56 | |||
57 | CFI_ENDPROC | ||
58 | |||
59 | ENDPROC(this_cpu_cmpxchg16b_emu) | ||