[tip:x86/asm] x86: Unify rwlock assembly implementation

From: tip-bot for Jan Beulich
Date: Thu Jul 21 2011 - 06:08:07 EST

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Commit-ID: 4625cd637919edfb562e0d62abf94f52e9321335
Gitweb: http://git.kernel.org/tip/4625cd637919edfb562e0d62abf94f52e9321335
Author: Jan Beulich <JBeulich@xxxxxxxxxx>
AuthorDate: Tue, 19 Jul 2011 12:59:51 +0100
Committer: Ingo Molnar <mingo@xxxxxxx>
CommitDate: Thu, 21 Jul 2011 09:03:31 +0200

x86: Unify rwlock assembly implementation

Rather than having two functionally identical implementations
for 32- and 64-bit configurations, extend the existing assembly
abstractions enough to fold the two rwlock implementations into
a shared one.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/4E258DD7020000780004E3EA@xxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/include/asm/asm.h | 3 +-
arch/x86/include/asm/frame.h | 11 +++++----
arch/x86/lib/Makefile | 6 +++-
arch/x86/lib/rwlock.S | 44 ++++++++++++++++++++++++++++++++++++++++++
arch/x86/lib/rwlock_64.S | 38 ------------------------------------
arch/x86/lib/semaphore_32.S | 44 ------------------------------------------
6 files changed, 56 insertions(+), 90 deletions(-)

diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index b3ed1e1..5890beb 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -15,7 +15,8 @@
# define __ASM_SEL(a,b) __ASM_FORM(b)
#endif

-#define __ASM_SIZE(inst) __ASM_SEL(inst##l, inst##q)
+#define __ASM_SIZE(inst, ...) __ASM_SEL(inst##l##__VA_ARGS__, \
+ inst##q##__VA_ARGS__)
#define __ASM_REG(reg) __ASM_SEL(e##reg, r##reg)

#define _ASM_PTR __ASM_SEL(.long, .quad)
diff --git a/arch/x86/include/asm/frame.h b/arch/x86/include/asm/frame.h
index 2c6fc9e..3b629f4 100644
--- a/arch/x86/include/asm/frame.h
+++ b/arch/x86/include/asm/frame.h
@@ -1,5 +1,6 @@
#ifdef __ASSEMBLY__

+#include <asm/asm.h>
#include <asm/dwarf2.h>

/* The annotation hides the frame from the unwinder and makes it look
@@ -7,13 +8,13 @@
frame pointer later */
#ifdef CONFIG_FRAME_POINTER
.macro FRAME
- pushl_cfi %ebp
- CFI_REL_OFFSET ebp,0
- movl %esp,%ebp
+ __ASM_SIZE(push,_cfi) %__ASM_REG(bp)
+ CFI_REL_OFFSET __ASM_REG(bp), 0
+ __ASM_SIZE(mov) %__ASM_REG(sp), %__ASM_REG(bp)
.endm
.macro ENDFRAME
- popl_cfi %ebp
- CFI_RESTORE ebp
+ __ASM_SIZE(pop,_cfi) %__ASM_REG(bp)
+ CFI_RESTORE __ASM_REG(bp)
.endm
#else
.macro FRAME
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f2479f1..d3ed120 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -20,6 +20,7 @@ lib-y := delay.o
lib-y += thunk_$(BITS).o
lib-y += usercopy_$(BITS).o getuser.o putuser.o
lib-y += memcpy_$(BITS).o
+lib-$(CONFIG_SMP) += rwlock.o
lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o

obj-y += msr.o msr-reg.o msr-reg-export.o
@@ -29,7 +30,8 @@ ifeq ($(CONFIG_X86_32),y)
lib-y += atomic64_cx8_32.o
lib-y += checksum_32.o
lib-y += strstr_32.o
- lib-y += semaphore_32.o string_32.o
+ lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += semaphore_32.o
+ lib-y += string_32.o
lib-y += cmpxchg.o
ifneq ($(CONFIG_X86_CMPXCHG64),y)
lib-y += cmpxchg8b_emu.o atomic64_386_32.o
@@ -40,7 +42,7 @@ else
lib-y += csum-partial_64.o csum-copy_64.o csum-wrappers_64.o
lib-y += thunk_64.o clear_page_64.o copy_page_64.o
lib-y += memmove_64.o memset_64.o
- lib-y += copy_user_64.o rwlock_64.o copy_user_nocache_64.o
+ lib-y += copy_user_64.o copy_user_nocache_64.o
lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem_64.o
lib-y += cmpxchg16b_emu.o
endif
diff --git a/arch/x86/lib/rwlock.S b/arch/x86/lib/rwlock.S
new file mode 100644
index 0000000..fca1782
--- /dev/null
+++ b/arch/x86/lib/rwlock.S
@@ -0,0 +1,44 @@
+/* Slow paths of read/write spinlocks. */
+
+#include <linux/linkage.h>
+#include <asm/alternative-asm.h>
+#include <asm/frame.h>
+#include <asm/rwlock.h>
+
+#ifdef CONFIG_X86_32
+# define __lock_ptr eax
+#else
+# define __lock_ptr rdi
+#endif
+
+ENTRY(__write_lock_failed)
+ CFI_STARTPROC
+ FRAME
+0: LOCK_PREFIX
+ addl $RW_LOCK_BIAS, (%__lock_ptr)
+1: rep; nop
+ cmpl $RW_LOCK_BIAS, (%__lock_ptr)
+ jne 1b
+ LOCK_PREFIX
+ subl $RW_LOCK_BIAS, (%__lock_ptr)
+ jnz 0b
+ ENDFRAME
+ ret
+ CFI_ENDPROC
+END(__write_lock_failed)
+
+ENTRY(__read_lock_failed)
+ CFI_STARTPROC
+ FRAME
+0: LOCK_PREFIX
+ incl (%__lock_ptr)
+1: rep; nop
+ cmpl $1, (%__lock_ptr)
+ js 1b
+ LOCK_PREFIX
+ decl (%__lock_ptr)
+ js 0b
+ ENDFRAME
+ ret
+ CFI_ENDPROC
+END(__read_lock_failed)
diff --git a/arch/x86/lib/rwlock_64.S b/arch/x86/lib/rwlock_64.S
deleted file mode 100644
index 05ea55f..0000000
--- a/arch/x86/lib/rwlock_64.S
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Slow paths of read/write spinlocks. */
-
-#include <linux/linkage.h>
-#include <asm/rwlock.h>
-#include <asm/alternative-asm.h>
-#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/lib/semaphore_32.S b/arch/x86/lib/semaphore_32.S
index 06691da..65b591d 100644
--- a/arch/x86/lib/semaphore_32.S
+++ b/arch/x86/lib/semaphore_32.S
@@ -14,8 +14,6 @@
*/

#include <linux/linkage.h>
-#include <asm/rwlock.h>
-#include <asm/alternative-asm.h>
#include <asm/frame.h>
#include <asm/dwarf2.h>

@@ -31,46 +29,6 @@
*/
.section .sched.text, "ax"

-/*
- * rw spinlock fallbacks
- */
-#ifdef CONFIG_SMP
-ENTRY(__write_lock_failed)
- CFI_STARTPROC
- FRAME
-2: LOCK_PREFIX
- addl $ RW_LOCK_BIAS,(%eax)
-1: rep; nop
- cmpl $ RW_LOCK_BIAS,(%eax)
- jne 1b
- LOCK_PREFIX
- subl $ RW_LOCK_BIAS,(%eax)
- jnz 2b
- ENDFRAME
- ret
- CFI_ENDPROC
- ENDPROC(__write_lock_failed)
-
-ENTRY(__read_lock_failed)
- CFI_STARTPROC
- FRAME
-2: LOCK_PREFIX
- incl (%eax)
-1: rep; nop
- cmpl $1,(%eax)
- js 1b
- LOCK_PREFIX
- decl (%eax)
- js 2b
- ENDFRAME
- ret
- CFI_ENDPROC
- ENDPROC(__read_lock_failed)
-
-#endif
-
-#ifdef CONFIG_RWSEM_XCHGADD_ALGORITHM
-
/* Fix up special calling conventions */
ENTRY(call_rwsem_down_read_failed)
CFI_STARTPROC
@@ -120,5 +78,3 @@ ENTRY(call_rwsem_downgrade_wake)
ret
CFI_ENDPROC
ENDPROC(call_rwsem_downgrade_wake)
-
-#endif
--
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Next message: tip-bot for Jan Beulich: "[tip:x86/asm] x86: Unify rwsem assembly implementation"
Previous message: tip-bot for Masami Hiramatsu: "[tip:perf/core] perf probe: Support adding probes on offline kernel modules"
In reply to: Jan Beulich: "[PATCH 1/3, resend] x86: unify rwlock assembly implementation"
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