From: Andi Kleen <ak@suse.de>
Date: Wed, 30 Aug 2006 17:37:14 +0000 (+0200)
Subject: [PATCH] i386: Remove alternative_smp
X-Git-Tag: v2.6.18-rc6~45
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c74932779fc6f61b4c30145863a17125c1a296c;p=linux-2.6

[PATCH] i386: Remove alternative_smp

The .fill causes miscompilations with some binutils version.

Instead just patch the lock prefix in the lock constructs. That is the
majority of the cost and should be good enough.

Cc: Gerd Hoffmann <kraxel@suse.de>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/include/asm-i386/alternative.h b/include/asm-i386/alternative.h
index bb3b6317c8..b01a7ec409 100644
--- a/include/asm-i386/alternative.h
+++ b/include/asm-i386/alternative.h
@@ -88,9 +88,6 @@ static inline void alternatives_smp_switch(int smp) {}
 /*
  * Alternative inline assembly for SMP.
  *
- * alternative_smp() takes two versions (SMP first, UP second) and is
- * for more complex stuff such as spinlocks.
- *
  * The LOCK_PREFIX macro defined here replaces the LOCK and
  * LOCK_PREFIX macros used everywhere in the source tree.
  *
@@ -110,21 +107,6 @@ static inline void alternatives_smp_switch(int smp) {}
  */
 
 #ifdef CONFIG_SMP
-#define alternative_smp(smpinstr, upinstr, args...)			\
-	asm volatile ("661:\n\t" smpinstr "\n662:\n" 			\
-		      ".section .smp_altinstructions,\"a\"\n"		\
-		      "  .align 4\n"					\
-		      "  .long 661b\n"            /* label */		\
-		      "  .long 663f\n"		  /* new instruction */	\
-		      "  .byte " __stringify(X86_FEATURE_UP) "\n"	\
-		      "  .byte 662b-661b\n"       /* sourcelen */	\
-		      "  .byte 664f-663f\n"       /* replacementlen */	\
-		      ".previous\n"					\
-		      ".section .smp_altinstr_replacement,\"awx\"\n"   	\
-		      "663:\n\t" upinstr "\n"     /* replacement */	\
-		      "664:\n\t.fill 662b-661b,1,0x42\n" /* space for original */ \
-		      ".previous" : args)
-
 #define LOCK_PREFIX \
 		".section .smp_locks,\"a\"\n"	\
 		"  .align 4\n"			\
@@ -133,8 +115,6 @@ static inline void alternatives_smp_switch(int smp) {}
 	       	"661:\n\tlock; "
 
 #else /* ! CONFIG_SMP */
-#define alternative_smp(smpinstr, upinstr, args...) \
-	asm volatile (upinstr : args)
 #define LOCK_PREFIX ""
 #endif
 
diff --git a/include/asm-i386/rwlock.h b/include/asm-i386/rwlock.h
index 96b0bef2ea..3ac1ba98b1 100644
--- a/include/asm-i386/rwlock.h
+++ b/include/asm-i386/rwlock.h
@@ -21,22 +21,20 @@
 #define RW_LOCK_BIAS_STR	"0x01000000"
 
 #define __build_read_lock_ptr(rw, helper)   \
-	alternative_smp("lock; subl $1,(%0)\n\t" \
+	asm volatile(LOCK_PREFIX " ; subl $1,(%0)\n\t" \
 			"jns 1f\n" \
 			"call " helper "\n\t" \
-			"1:\n", \
-			"subl $1,(%0)\n\t", \
+			"1:\n" \
 			:"a" (rw) : "memory")
 
 #define __build_read_lock_const(rw, helper)   \
-	alternative_smp("lock; subl $1,%0\n\t" \
+	asm volatile(LOCK_PREFIX " ; subl $1,%0\n\t" \
 			"jns 1f\n" \
 			"pushl %%eax\n\t" \
 			"leal %0,%%eax\n\t" \
 			"call " helper "\n\t" \
 			"popl %%eax\n\t" \
-			"1:\n", \
-			"subl $1,%0\n\t", \
+			"1:\n" : \
 			"+m" (*(volatile int *)rw) : : "memory")
 
 #define __build_read_lock(rw, helper)	do { \
@@ -47,7 +45,7 @@
 					} while (0)
 
 #define __build_write_lock_ptr(rw, helper) \
-	alternative_smp("lock; subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
+	asm volatile(LOCK_PREFIX " ; subl $" RW_LOCK_BIAS_STR ",(%0)\n\t" \
 			"jz 1f\n" \
 			"call " helper "\n\t" \
 			"1:\n", \
@@ -55,7 +53,7 @@
 			:"a" (rw) : "memory")
 
 #define __build_write_lock_const(rw, helper) \
-	alternative_smp("lock; subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
+	asm volatile(LOCK_PREFIX " ; subl $" RW_LOCK_BIAS_STR ",%0\n\t" \
 			"jz 1f\n" \
 			"pushl %%eax\n\t" \
 			"leal %0,%%eax\n\t" \
diff --git a/include/asm-i386/spinlock.h b/include/asm-i386/spinlock.h
index d816c62a7a..d1020363c4 100644
--- a/include/asm-i386/spinlock.h
+++ b/include/asm-i386/spinlock.h
@@ -22,7 +22,7 @@
 
 #define __raw_spin_lock_string \
 	"\n1:\t" \
-	"lock ; decb %0\n\t" \
+	LOCK_PREFIX " ; decb %0\n\t" \
 	"jns 3f\n" \
 	"2:\t" \
 	"rep;nop\n\t" \
@@ -38,7 +38,7 @@
  */
 #define __raw_spin_lock_string_flags \
 	"\n1:\t" \
-	"lock ; decb %0\n\t" \
+	LOCK_PREFIX " ; decb %0\n\t" \
 	"jns 5f\n" \
 	"2:\t" \
 	"testl $0x200, %1\n\t" \
@@ -57,15 +57,9 @@
 	"jmp 4b\n" \
 	"5:\n\t"
 
-#define __raw_spin_lock_string_up \
-	"\n\tdecb %0"
-
 static inline void __raw_spin_lock(raw_spinlock_t *lock)
 {
-	alternative_smp(
-		__raw_spin_lock_string,
-		__raw_spin_lock_string_up,
-		"+m" (lock->slock) : : "memory");
+	asm(__raw_spin_lock_string : "+m" (lock->slock) : : "memory");
 }
 
 /*
@@ -76,10 +70,7 @@ static inline void __raw_spin_lock(raw_spinlock_t *lock)
 #ifndef CONFIG_PROVE_LOCKING
 static inline void __raw_spin_lock_flags(raw_spinlock_t *lock, unsigned long flags)
 {
-	alternative_smp(
-		__raw_spin_lock_string_flags,
-		__raw_spin_lock_string_up,
-		"+m" (lock->slock) : "r" (flags) : "memory");
+	asm(__raw_spin_lock_string_flags : "+m" (lock->slock) : "r" (flags) : "memory");
 }
 #endif