[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, 25 insertions, 13 deletions

diff --git a/arch/x86_64/kernel/module.c b/arch/x86_64/kernel/module.c
index bac195c74bcc..9d0958ff547f 100644
--- a/arch/x86_64/kernel/module.c
+++ b/arch/x86_64/kernel/module.c
@@ -145,26 +145,38 @@ int apply_relocate(Elf_Shdr *sechdrs,
         return -ENOSYS;
 } 
 
-extern void apply_alternatives(void *start, void *end); 
-
 int module_finalize(const Elf_Ehdr *hdr,
-                    const Elf_Shdr *sechdrs,
-                    struct module *me)
+                    const Elf_Shdr *sechdrs,
+                    struct module *me)
 {
-        const Elf_Shdr *s;
+        const Elf_Shdr *s, *text = NULL, *alt = NULL, *locks = NULL;
         char *secstrings = (void *)hdr + sechdrs[hdr->e_shstrndx].sh_offset;
 
-        /* look for .altinstructions to patch */ 
-        for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) { 
-                void *seg;              
-                if (strcmp(".altinstructions", secstrings + s->sh_name))
-                        continue;
-                seg = (void *)s->sh_addr; 
-                apply_alternatives(seg, seg + s->sh_size); 
-        }       
+        for (s = sechdrs; s < sechdrs + hdr->e_shnum; s++) {
+                if (!strcmp(".text", secstrings + s->sh_name))
+                        text = s;
+                if (!strcmp(".altinstructions", secstrings + s->sh_name))
+                        alt = s;
+                if (!strcmp(".smp_locks", secstrings + s->sh_name))
+                        locks= s;
+        }
+
+        if (alt) {
+                /* patch .altinstructions */
+                void *aseg = (void *)alt->sh_addr;
+                apply_alternatives(aseg, aseg + alt->sh_size);
+        }
+        if (locks && text) {
+                void *lseg = (void *)locks->sh_addr;
+                void *tseg = (void *)text->sh_addr;
+                alternatives_smp_module_add(me, me->name,
+                                            lseg, lseg + locks->sh_size,
+                                            tseg, tseg + text->sh_size);
+        }
         return 0;
 }
 
 void module_arch_cleanup(struct module *mod)
 {
+        alternatives_smp_module_del(mod);
 }