1 files changed, 44 insertions, 58 deletions

diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 426f59b0106b..d8cda14fff8b 100644
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -5,6 +5,7 @@
 #include <asm/alternative.h>
 #include <asm/sections.h>
 
+static int noreplace_smp     = 0;
 static int smp_alt_once      = 0;
 static int debug_alternative = 0;
 
@@ -13,15 +14,33 @@ static int __init bootonly(char *str)
         smp_alt_once = 1;
         return 1;
 }
+__setup("smp-alt-boot", bootonly);
+
 static int __init debug_alt(char *str)
 {
         debug_alternative = 1;
         return 1;
 }
-
-__setup("smp-alt-boot", bootonly);
 __setup("debug-alternative", debug_alt);
 
+static int __init setup_noreplace_smp(char *str)
+{
+        noreplace_smp = 1;
+        return 1;
+}
+__setup("noreplace-smp", setup_noreplace_smp);
+
+#ifdef CONFIG_PARAVIRT
+static int noreplace_paravirt = 0;
+
+static int __init setup_noreplace_paravirt(char *str)
+{
+        noreplace_paravirt = 1;
+        return 1;
+}
+__setup("noreplace-paravirt", setup_noreplace_paravirt);
+#endif
+
 #define DPRINTK(fmt, args...) if (debug_alternative) \
         printk(KERN_DEBUG fmt, args)
 
@@ -132,11 +151,8 @@ static void nop_out(void *insns, unsigned int len)
 }
 
 extern struct alt_instr __alt_instructions[], __alt_instructions_end[];
-extern struct alt_instr __smp_alt_instructions[], __smp_alt_instructions_end[];
 extern u8 *__smp_locks[], *__smp_locks_end[];
 
-extern u8 __smp_alt_begin[], __smp_alt_end[];
-
 /* Replace instructions with better alternatives for this CPU type.
    This runs before SMP is initialized to avoid SMP problems with
    self modifying code. This implies that assymetric systems where
@@ -171,29 +187,6 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
 
 #ifdef CONFIG_SMP
 
-static void alternatives_smp_save(struct alt_instr *start, struct alt_instr *end)
-{
-        struct alt_instr *a;
-
-        DPRINTK("%s: alt table %p-%p\n", __FUNCTION__, start, end);
-        for (a = start; a < end; a++) {
-                memcpy(a->replacement + a->replacementlen,
-                       a->instr,
-                       a->instrlen);
-        }
-}
-
-static void alternatives_smp_apply(struct alt_instr *start, struct alt_instr *end)
-{
-        struct alt_instr *a;
-
-        for (a = start; a < end; a++) {
-                memcpy(a->instr,
-                       a->replacement + a->replacementlen,
-                       a->instrlen);
-        }
-}
-
 static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
 {
         u8 **ptr;
@@ -211,6 +204,9 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end
 {
         u8 **ptr;
 
+        if (noreplace_smp)
+                return;
+
         for (ptr = start; ptr < end; ptr++) {
                 if (*ptr < text)
                         continue;
@@ -245,6 +241,9 @@ void alternatives_smp_module_add(struct module *mod, char *name,
         struct smp_alt_module *smp;
         unsigned long flags;
 
+        if (noreplace_smp)
+                return;
+
         if (smp_alt_once) {
                 if (boot_cpu_has(X86_FEATURE_UP))
                         alternatives_smp_unlock(locks, locks_end,
@@ -279,7 +278,7 @@ void alternatives_smp_module_del(struct module *mod)
         struct smp_alt_module *item;
         unsigned long flags;
 
-        if (smp_alt_once)
+        if (smp_alt_once || noreplace_smp)
                 return;
 
         spin_lock_irqsave(&smp_alt, flags);
@@ -310,7 +309,7 @@ void alternatives_smp_switch(int smp)
         return;
 #endif
 
-        if (smp_alt_once)
+        if (noreplace_smp || smp_alt_once)
                 return;
         BUG_ON(!smp && (num_online_cpus() > 1));
 
@@ -319,8 +318,6 @@ void alternatives_smp_switch(int smp)
                 printk(KERN_INFO "SMP alternatives: switching to SMP code\n");
                 clear_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
                 clear_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-                alternatives_smp_apply(__smp_alt_instructions,
-                                       __smp_alt_instructions_end);
                 list_for_each_entry(mod, &smp_alt_modules, next)
                         alternatives_smp_lock(mod->locks, mod->locks_end,
                                               mod->text, mod->text_end);
@@ -328,8 +325,6 @@ void alternatives_smp_switch(int smp)
                 printk(KERN_INFO "SMP alternatives: switching to UP code\n");
                 set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
                 set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-                apply_alternatives(__smp_alt_instructions,
-                                   __smp_alt_instructions_end);
                 list_for_each_entry(mod, &smp_alt_modules, next)
                         alternatives_smp_unlock(mod->locks, mod->locks_end,
                                                 mod->text, mod->text_end);
@@ -340,36 +335,31 @@ void alternatives_smp_switch(int smp)
 #endif
 
 #ifdef CONFIG_PARAVIRT
-void apply_paravirt(struct paravirt_patch *start, struct paravirt_patch *end)
+void apply_paravirt(struct paravirt_patch_site *start,
+                    struct paravirt_patch_site *end)
 {
-        struct paravirt_patch *p;
+        struct paravirt_patch_site *p;
+
+        if (noreplace_paravirt)
+                return;
 
         for (p = start; p < end; p++) {
                 unsigned int used;
 
                 used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr,
                                           p->len);
-#ifdef CONFIG_DEBUG_PARAVIRT
-                {
-                int i;
-                /* Deliberately clobber regs using "not %reg" to find bugs. */
-                for (i = 0; i < 3; i++) {
-                        if (p->len - used >= 2 && (p->clobbers & (1 << i))) {
-                                memcpy(p->instr + used, "\xf7\xd0", 2);
-                                p->instr[used+1] |= i;
-                                used += 2;
-                        }
-                }
-                }
-#endif
+
+                BUG_ON(used > p->len);
+
                 /* Pad the rest with nops */
                 nop_out(p->instr + used, p->len - used);
         }
 
-        /* Sync to be conservative, in case we patched following instructions */
+        /* Sync to be conservative, in case we patched following
+         * instructions */
         sync_core();
 }
-extern struct paravirt_patch __start_parainstructions[],
+extern struct paravirt_patch_site __start_parainstructions[],
         __stop_parainstructions[];
 #endif  /* CONFIG_PARAVIRT */
 
@@ -396,23 +386,19 @@ void __init alternative_instructions(void)
                         printk(KERN_INFO "SMP alternatives: switching to UP code\n");
                         set_bit(X86_FEATURE_UP, boot_cpu_data.x86_capability);
                         set_bit(X86_FEATURE_UP, cpu_data[0].x86_capability);
-                        apply_alternatives(__smp_alt_instructions,
-                                           __smp_alt_instructions_end);
                         alternatives_smp_unlock(__smp_locks, __smp_locks_end,
                                                 _text, _etext);
                 }
                 free_init_pages("SMP alternatives",
-                                (unsigned long)__smp_alt_begin,
-                                (unsigned long)__smp_alt_end);
+                                (unsigned long)__smp_locks,
+                                (unsigned long)__smp_locks_end);
         } else {
-                alternatives_smp_save(__smp_alt_instructions,
-                                      __smp_alt_instructions_end);
                 alternatives_smp_module_add(NULL, "core kernel",
                                             __smp_locks, __smp_locks_end,
                                             _text, _etext);
                 alternatives_smp_switch(0);
         }
 #endif
-        apply_paravirt(__start_parainstructions, __stop_parainstructions);
+        apply_paravirt(__parainstructions, __parainstructions_end);
         local_irq_restore(flags);
 }