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authorAndi Kleen <ak@suse.de>2006-09-26 10:52:28 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:28 +0200
commit9a0b26e6bc4ae1979d9bcc6194e57a71b2b5cac6 (patch)
tree01601a502007b85d4fc88f79de7a93c257ef9d97 /arch/x86_64/lib
parentb4062b16094038334d9bbadac0397a3fc9e981b0 (diff)
downloadlinux-linaro-stable-9a0b26e6bc4ae1979d9bcc6194e57a71b2b5cac6.tar.gz
[PATCH] Clean up read write lock assembly
- Move the slow path fallbacks to their own assembly files This makes them much easier to read and is needed for the next change. - Add CFI annotations for unwinding (XXX need review) - Remove constant case which can never happen with out of line spinlocks - Use patchable LOCK prefixes - Don't use lock sections anymore for inline code because they can't be expressed by the unwinder (this adds one taken jump to the lock fast path) Cc: jbeulich@novell.com Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/x86_64/lib')
-rw-r--r--arch/x86_64/lib/Makefile2
-rw-r--r--arch/x86_64/lib/rwlock.S38
-rw-r--r--arch/x86_64/lib/thunk.S30
3 files changed, 39 insertions, 31 deletions
diff --git a/arch/x86_64/lib/Makefile b/arch/x86_64/lib/Makefile
index ccef6ae747a3..b78d4170fce2 100644
--- a/arch/x86_64/lib/Makefile
+++ b/arch/x86_64/lib/Makefile
@@ -9,4 +9,4 @@ obj-y := io.o iomap_copy.o
lib-y := csum-partial.o csum-copy.o csum-wrappers.o delay.o \
usercopy.o getuser.o putuser.o \
thunk.o clear_page.o copy_page.o bitstr.o bitops.o
-lib-y += memcpy.o memmove.o memset.o copy_user.o
+lib-y += memcpy.o memmove.o memset.o copy_user.o rwlock.o
diff --git a/arch/x86_64/lib/rwlock.S b/arch/x86_64/lib/rwlock.S
new file mode 100644
index 000000000000..0cde1f807314
--- /dev/null
+++ b/arch/x86_64/lib/rwlock.S
@@ -0,0 +1,38 @@
+/* Slow paths of read/write spinlocks. */
+
+#include <linux/linkage.h>
+#include <asm/rwlock.h>
+#include <asm/alternative-asm.i>
+#include <asm/dwarf2.h>
+
+/* rdi: pointer to rwlock_t */
+ENTRY(__write_lock_failed)
+ CFI_STARTPROC
+ LOCK_PREFIX
+ addl $RW_LOCK_BIAS,(%rdi)
+1: rep
+ nop
+ cmpl $RW_LOCK_BIAS,(%rdi)
+ jne 1b
+ LOCK_PREFIX
+ subl $RW_LOCK_BIAS,(%rdi)
+ jnz __write_lock_failed
+ ret
+ CFI_ENDPROC
+END(__write_lock_failed)
+
+/* rdi: pointer to rwlock_t */
+ENTRY(__read_lock_failed)
+ CFI_STARTPROC
+ LOCK_PREFIX
+ incl (%rdi)
+1: rep
+ nop
+ cmpl $1,(%rdi)
+ js 1b
+ LOCK_PREFIX
+ decl (%rdi)
+ js __read_lock_failed
+ ret
+ CFI_ENDPROC
+END(__read_lock_failed)
diff --git a/arch/x86_64/lib/thunk.S b/arch/x86_64/lib/thunk.S
index 332ea5dff916..6cff27c775ae 100644
--- a/arch/x86_64/lib/thunk.S
+++ b/arch/x86_64/lib/thunk.S
@@ -67,33 +67,3 @@ restore_norax:
RESTORE_ARGS 1
ret
CFI_ENDPROC
-
-#ifdef CONFIG_SMP
-/* Support for read/write spinlocks. */
- .text
-/* rax: pointer to rwlock_t */
-ENTRY(__write_lock_failed)
- lock
- addl $RW_LOCK_BIAS,(%rax)
-1: rep
- nop
- cmpl $RW_LOCK_BIAS,(%rax)
- jne 1b
- lock
- subl $RW_LOCK_BIAS,(%rax)
- jnz __write_lock_failed
- ret
-
-/* rax: pointer to rwlock_t */
-ENTRY(__read_lock_failed)
- lock
- incl (%rax)
-1: rep
- nop
- cmpl $1,(%rax)
- js 1b
- lock
- decl (%rax)
- js __read_lock_failed
- ret
-#endif