[PATCH] x86_64: x86_64 version of the smp alternative patch.

Changes are largely identical to the i386 version:

 * alternative #define are moved to the new alternative.h file.
 * one new elf section with pointers to the lock prefixes which can be
   nop'ed out for non-smp.
 * two new elf sections simliar to the "classic" alternatives to
   replace SMP code with simpler UP code.
 * fixup headers to use alternative.h instead of defining their own
   LOCK / LOCK_PREFIX macros.

The patch reuses the i386 version of the alternatives code to avoid code
duplication.  The code in alternatives.c was shuffled around a bit to
reduce the number of #ifdefs needed.  It also got some tweaks needed for
x86_64 (vsyscall page handling) and new features (noreplacement option
which was x86_64 only up to now).  Debug printk's are changed from
compile-time to runtime.

Loosely based on a early version from Bastian Blank <waldi@debian.org>

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

1 files changed, 3 insertions, 83 deletions

diff --git a/include/asm-x86_64/system.h b/include/asm-x86_64/system.h
index f48e0dad8b3d..68e559f3631c 100644
--- a/include/asm-x86_64/system.h
+++ b/include/asm-x86_64/system.h
@@ -3,15 +3,10 @@
 
 #include <linux/kernel.h>
 #include <asm/segment.h>
+#include <asm/alternative.h>
 
 #ifdef __KERNEL__
 
-#ifdef CONFIG_SMP
-#define LOCK_PREFIX "lock ; "
-#else
-#define LOCK_PREFIX ""
-#endif
-
 #define __STR(x) #x
 #define STR(x) __STR(x)
 
@@ -34,7 +29,7 @@
                      "thread_return:\n\t"                                           \
                      "movq %%gs:%P[pda_pcurrent],%%rsi\n\t"                       \
                      "movq %P[thread_info](%%rsi),%%r8\n\t"                       \
-                     LOCK "btr  %[tif_fork],%P[ti_flags](%%r8)\n\t"               \
+                     LOCK_PREFIX "btr  %[tif_fork],%P[ti_flags](%%r8)\n\t"        \
                      "movq %%rax,%%rdi\n\t"                                       \
                      "jc   ret_from_fork\n\t"                                     \
                      RESTORE_CONTEXT                                                \
@@ -69,82 +64,6 @@ extern void load_gs_index(unsigned);
                 ".previous"                     \
                 : :"r" (value), "r" (0))
 
-#ifdef __KERNEL__
-struct alt_instr { 
-        __u8 *instr;            /* original instruction */
-        __u8 *replacement;
-        __u8  cpuid;            /* cpuid bit set for replacement */
-        __u8  instrlen;         /* length of original instruction */
-        __u8  replacementlen;   /* length of new instruction, <= instrlen */ 
-        __u8  pad[5];
-}; 
-#endif
-
-/*
- * Alternative instructions for different CPU types or capabilities.
- * 
- * This allows to use optimized instructions even on generic binary
- * kernels.
- * 
- * length of oldinstr must be longer or equal the length of newinstr
- * It can be padded with nops as needed.
- * 
- * For non barrier like inlines please define new variants
- * without volatile and memory clobber.
- */
-#define alternative(oldinstr, newinstr, feature)        \
-        asm volatile ("661:\n\t" oldinstr "\n662:\n"                 \
-                      ".section .altinstructions,\"a\"\n"            \
-                      "  .align 8\n"                                   \
-                      "  .quad 661b\n"            /* label */          \
-                      "  .quad 663f\n"            /* new instruction */ \
-                      "  .byte %c0\n"             /* feature bit */    \
-                      "  .byte 662b-661b\n"       /* sourcelen */      \
-                      "  .byte 664f-663f\n"       /* replacementlen */ \
-                      ".previous\n"                                     \
-                      ".section .altinstr_replacement,\"ax\"\n"         \
-                      "663:\n\t" newinstr "\n664:\n"   /* replacement */ \
-                      ".previous" :: "i" (feature) : "memory")  
-
-/*
- * Alternative inline assembly with input.
- * 
- * Peculiarities:
- * No memory clobber here. 
- * Argument numbers start with 1.
- * Best is to use constraints that are fixed size (like (%1) ... "r")
- * If you use variable sized constraints like "m" or "g" in the 
- * replacement make sure to pad to the worst case length.
- */
-#define alternative_input(oldinstr, newinstr, feature, input...)        \
-        asm volatile ("661:\n\t" oldinstr "\n662:\n"                    \
-                      ".section .altinstructions,\"a\"\n"               \
-                      "  .align 8\n"                                    \
-                      "  .quad 661b\n"            /* label */           \
-                      "  .quad 663f\n"            /* new instruction */ \
-                      "  .byte %c0\n"             /* feature bit */     \
-                      "  .byte 662b-661b\n"       /* sourcelen */       \
-                      "  .byte 664f-663f\n"       /* replacementlen */  \
-                      ".previous\n"                                     \
-                      ".section .altinstr_replacement,\"ax\"\n"         \
-                      "663:\n\t" newinstr "\n664:\n"   /* replacement */ \
-                      ".previous" :: "i" (feature), ##input)
-
-/* Like alternative_input, but with a single output argument */
-#define alternative_io(oldinstr, newinstr, feature, output, input...) \
-        asm volatile ("661:\n\t" oldinstr "\n662:\n"                    \
-                      ".section .altinstructions,\"a\"\n"               \
-                      "  .align 8\n"                                    \
-                      "  .quad 661b\n"            /* label */           \
-                      "  .quad 663f\n"            /* new instruction */ \
-                      "  .byte %c[feat]\n"        /* feature bit */     \
-                      "  .byte 662b-661b\n"       /* sourcelen */       \
-                      "  .byte 664f-663f\n"       /* replacementlen */  \
-                      ".previous\n"                                     \
-                      ".section .altinstr_replacement,\"ax\"\n"         \
-                      "663:\n\t" newinstr "\n664:\n"   /* replacement */ \
-                      ".previous" : output : [feat] "i" (feature), ##input)
-
 /*
  * Clear and set 'TS' bit respectively
  */
@@ -366,5 +285,6 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
 void cpu_idle_wait(void);
 
 extern unsigned long arch_align_stack(unsigned long sp);
+extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
 
 #endif