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Diffstat (limited to 'arch/i386/kernel/alternative.c')
-rw-r--r--arch/i386/kernel/alternative.c102
1 files changed, 44 insertions, 58 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 426f59b0106b..e5cec6685cc5 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);
+ __pa_symbol(&__smp_locks),
+ __pa_symbol(&__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);
}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.