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-rw-r--r--arch/i386/kernel/alternative.c124
1 files changed, 91 insertions, 33 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 5cbd6f99fb2..7b421b3a053 100644
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -4,27 +4,41 @@
#include <asm/alternative.h>
#include <asm/sections.h>
-#define DEBUG 0
-#if DEBUG
-# define DPRINTK(fmt, args...) printk(fmt, args)
-#else
-# define DPRINTK(fmt, args...)
-#endif
+static int no_replacement = 0;
+static int smp_alt_once = 0;
+static int debug_alternative = 0;
+static int __init noreplacement_setup(char *s)
+{
+ no_replacement = 1;
+ return 1;
+}
+static int __init bootonly(char *str)
+{
+ smp_alt_once = 1;
+ return 1;
+}
+static int __init debug_alt(char *str)
+{
+ debug_alternative = 1;
+ return 1;
+}
+
+__setup("noreplacement", noreplacement_setup);
+__setup("smp-alt-boot", bootonly);
+__setup("debug-alternative", debug_alt);
+
+#define DPRINTK(fmt, args...) if (debug_alternative) \
+ printk(KERN_DEBUG fmt, args)
+
+#ifdef GENERIC_NOP1
/* Use inline assembly to define this because the nops are defined
as inline assembly strings in the include files and we cannot
get them easily into strings. */
asm("\t.data\nintelnops: "
GENERIC_NOP1 GENERIC_NOP2 GENERIC_NOP3 GENERIC_NOP4 GENERIC_NOP5 GENERIC_NOP6
GENERIC_NOP7 GENERIC_NOP8);
-asm("\t.data\nk8nops: "
- K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6
- K8_NOP7 K8_NOP8);
-asm("\t.data\nk7nops: "
- K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6
- K7_NOP7 K7_NOP8);
-
-extern unsigned char intelnops[], k8nops[], k7nops[];
+extern unsigned char intelnops[];
static unsigned char *intel_nops[ASM_NOP_MAX+1] = {
NULL,
intelnops,
@@ -36,6 +50,13 @@ static unsigned char *intel_nops[ASM_NOP_MAX+1] = {
intelnops + 1 + 2 + 3 + 4 + 5 + 6,
intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
};
+#endif
+
+#ifdef K8_NOP1
+asm("\t.data\nk8nops: "
+ K8_NOP1 K8_NOP2 K8_NOP3 K8_NOP4 K8_NOP5 K8_NOP6
+ K8_NOP7 K8_NOP8);
+extern unsigned char k8nops[];
static unsigned char *k8_nops[ASM_NOP_MAX+1] = {
NULL,
k8nops,
@@ -47,6 +68,13 @@ static unsigned char *k8_nops[ASM_NOP_MAX+1] = {
k8nops + 1 + 2 + 3 + 4 + 5 + 6,
k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
};
+#endif
+
+#ifdef K7_NOP1
+asm("\t.data\nk7nops: "
+ K7_NOP1 K7_NOP2 K7_NOP3 K7_NOP4 K7_NOP5 K7_NOP6
+ K7_NOP7 K7_NOP8);
+extern unsigned char k7nops[];
static unsigned char *k7_nops[ASM_NOP_MAX+1] = {
NULL,
k7nops,
@@ -58,6 +86,18 @@ static unsigned char *k7_nops[ASM_NOP_MAX+1] = {
k7nops + 1 + 2 + 3 + 4 + 5 + 6,
k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7,
};
+#endif
+
+#ifdef CONFIG_X86_64
+
+extern char __vsyscall_0;
+static inline unsigned char** find_nop_table(void)
+{
+ return k8_nops;
+}
+
+#else /* CONFIG_X86_64 */
+
static struct nop {
int cpuid;
unsigned char **noptable;
@@ -67,14 +107,6 @@ static struct nop {
{ -1, NULL }
};
-
-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[];
-
-
static unsigned char** find_nop_table(void)
{
unsigned char **noptable = intel_nops;
@@ -89,6 +121,14 @@ static unsigned char** find_nop_table(void)
return noptable;
}
+#endif /* CONFIG_X86_64 */
+
+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
@@ -99,6 +139,7 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
{
unsigned char **noptable = find_nop_table();
struct alt_instr *a;
+ u8 *instr;
int diff, i, k;
DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end);
@@ -106,7 +147,16 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end)
BUG_ON(a->replacementlen > a->instrlen);
if (!boot_cpu_has(a->cpuid))
continue;
- memcpy(a->instr, a->replacement, a->replacementlen);
+ instr = a->instr;
+#ifdef CONFIG_X86_64
+ /* vsyscall code is not mapped yet. resolve it manually. */
+ if (instr >= (u8 *)VSYSCALL_START && instr < (u8*)VSYSCALL_END) {
+ instr = __va(instr - (u8*)VSYSCALL_START + (u8*)__pa_symbol(&__vsyscall_0));
+ DPRINTK("%s: vsyscall fixup: %p => %p\n",
+ __FUNCTION__, a->instr, instr);
+ }
+#endif
+ memcpy(instr, a->replacement, a->replacementlen);
diff = a->instrlen - a->replacementlen;
/* Pad the rest with nops */
for (i = a->replacementlen; diff > 0; diff -= k, i += k) {
@@ -118,6 +168,8 @@ 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;
@@ -186,14 +238,6 @@ struct smp_alt_module {
static LIST_HEAD(smp_alt_modules);
static DEFINE_SPINLOCK(smp_alt);
-static int smp_alt_once = 0;
-static int __init bootonly(char *str)
-{
- smp_alt_once = 1;
- return 1;
-}
-__setup("smp-alt-boot", bootonly);
-
void alternatives_smp_module_add(struct module *mod, char *name,
void *locks, void *locks_end,
void *text, void *text_end)
@@ -201,6 +245,9 @@ void alternatives_smp_module_add(struct module *mod, char *name,
struct smp_alt_module *smp;
unsigned long flags;
+ if (no_replacement)
+ return;
+
if (smp_alt_once) {
if (boot_cpu_has(X86_FEATURE_UP))
alternatives_smp_unlock(locks, locks_end,
@@ -235,7 +282,7 @@ void alternatives_smp_module_del(struct module *mod)
struct smp_alt_module *item;
unsigned long flags;
- if (smp_alt_once)
+ if (no_replacement || smp_alt_once)
return;
spin_lock_irqsave(&smp_alt, flags);
@@ -256,7 +303,7 @@ void alternatives_smp_switch(int smp)
struct smp_alt_module *mod;
unsigned long flags;
- if (smp_alt_once)
+ if (no_replacement || smp_alt_once)
return;
BUG_ON(!smp && (num_online_cpus() > 1));
@@ -283,8 +330,17 @@ void alternatives_smp_switch(int smp)
spin_unlock_irqrestore(&smp_alt, flags);
}
+#endif
+
void __init alternative_instructions(void)
{
+ if (no_replacement) {
+ printk(KERN_INFO "(SMP-)alternatives turned off\n");
+ free_init_pages("SMP alternatives",
+ (unsigned long)__smp_alt_begin,
+ (unsigned long)__smp_alt_end);
+ return;
+ }
apply_alternatives(__alt_instructions, __alt_instructions_end);
/* switch to patch-once-at-boottime-only mode and free the
@@ -297,6 +353,7 @@ void __init alternative_instructions(void)
smp_alt_once = 1;
#endif
+#ifdef CONFIG_SMP
if (smp_alt_once) {
if (1 == num_possible_cpus()) {
printk(KERN_INFO "SMP alternatives: switching to UP code\n");
@@ -318,4 +375,5 @@ void __init alternative_instructions(void)
_text, _etext);
alternatives_smp_switch(0);
}
+#endif
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-25 01:04:30 +0000