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@novell.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4E258DD7020000780004E3EA@nat28.tlf.novell.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>

4 files changed, 48 insertions, 84 deletions

diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index f2479f19ddde..d3ed1203cdd7 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 000000000000..fca17829caa8
--- /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 05ea55f71405..000000000000
--- 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 06691daa4108..65b591d778b1 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