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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-28 21:41:35 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-02-28 21:41:35 +0300 |
| commit | d6cd4715e21508bebbb1928c91d628bd65f5de5f (patch) | |
| tree | 2b89de4d36032bdd3d56fbae6e0d626c2cdd38b8 /arch/x86/lib | |
| parent | 1eca9acbf9cda6437db7de1097c7a18014b1289d (diff) | |
| parent | 0d1622d7f526311d87d7da2ee7dd14b73e45d3fc (diff) | |
| download | linux-d6cd4715e21508bebbb1928c91d628bd65f5de5f.tar.xz | |
Merge branch 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-rwsem-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86-64, rwsem: Avoid store forwarding hazard in __downgrade_write
x86-64, rwsem: 64-bit xadd rwsem implementation
x86: Fix breakage of UML from the changes in the rwsem system
x86-64: support native xadd rwsem implementation
x86: clean up rwsem type system
Diffstat (limited to 'arch/x86/lib')
| -rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/lib/rwsem_64.S | 81 |
2 files changed, 82 insertions, 0 deletions
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 710cc1405866..419386c24b82 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -39,4 +39,5 @@ else lib-y += thunk_64.o clear_page_64.o copy_page_64.o lib-y += memmove_64.o memset_64.o lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o + lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o endif diff --git a/arch/x86/lib/rwsem_64.S b/arch/x86/lib/rwsem_64.S new file mode 100644 index 000000000000..15acecf0d7aa --- /dev/null +++ b/arch/x86/lib/rwsem_64.S @@ -0,0 +1,81 @@ +/* + * x86-64 rwsem wrappers + * + * This interfaces the inline asm code to the slow-path + * C routines. We need to save the call-clobbered regs + * that the asm does not mark as clobbered, and move the + * argument from %rax to %rdi. + * + * NOTE! We don't need to save %rax, because the functions + * will always return the semaphore pointer in %rax (which + * is also the input argument to these helpers) + * + * The following can clobber %rdx because the asm clobbers it: + * call_rwsem_down_write_failed + * call_rwsem_wake + * but %rdi, %rsi, %rcx, %r8-r11 always need saving. + */ + +#include <linux/linkage.h> +#include <asm/rwlock.h> +#include <asm/alternative-asm.h> +#include <asm/frame.h> +#include <asm/dwarf2.h> + +#define save_common_regs \ + pushq %rdi; \ + pushq %rsi; \ + pushq %rcx; \ + pushq %r8; \ + pushq %r9; \ + pushq %r10; \ + pushq %r11 + +#define restore_common_regs \ + popq %r11; \ + popq %r10; \ + popq %r9; \ + popq %r8; \ + popq %rcx; \ + popq %rsi; \ + popq %rdi + +/* Fix up special calling conventions */ +ENTRY(call_rwsem_down_read_failed) + save_common_regs + pushq %rdx + movq %rax,%rdi + call rwsem_down_read_failed + popq %rdx + restore_common_regs + ret + ENDPROC(call_rwsem_down_read_failed) + +ENTRY(call_rwsem_down_write_failed) + save_common_regs + movq %rax,%rdi + call rwsem_down_write_failed + restore_common_regs + ret + ENDPROC(call_rwsem_down_write_failed) + +ENTRY(call_rwsem_wake) + decw %dx /* do nothing if still outstanding active readers */ + jnz 1f + save_common_regs + movq %rax,%rdi + call rwsem_wake + restore_common_regs +1: ret + ENDPROC(call_rwsem_wake) + +/* Fix up special calling conventions */ +ENTRY(call_rwsem_downgrade_wake) + save_common_regs + pushq %rdx + movq %rax,%rdi + call rwsem_downgrade_wake + popq %rdx + restore_common_regs + ret + ENDPROC(call_rwsem_downgrade_wake) |