394 lines
9.7 KiB
C
394 lines
9.7 KiB
C
#include <linux/module.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/list.h>
|
|
#include <asm/alternative.h>
|
|
#include <asm/sections.h>
|
|
|
|
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);
|
|
extern unsigned char intelnops[];
|
|
static unsigned char *intel_nops[ASM_NOP_MAX+1] = {
|
|
NULL,
|
|
intelnops,
|
|
intelnops + 1,
|
|
intelnops + 1 + 2,
|
|
intelnops + 1 + 2 + 3,
|
|
intelnops + 1 + 2 + 3 + 4,
|
|
intelnops + 1 + 2 + 3 + 4 + 5,
|
|
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,
|
|
k8nops + 1,
|
|
k8nops + 1 + 2,
|
|
k8nops + 1 + 2 + 3,
|
|
k8nops + 1 + 2 + 3 + 4,
|
|
k8nops + 1 + 2 + 3 + 4 + 5,
|
|
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,
|
|
k7nops + 1,
|
|
k7nops + 1 + 2,
|
|
k7nops + 1 + 2 + 3,
|
|
k7nops + 1 + 2 + 3 + 4,
|
|
k7nops + 1 + 2 + 3 + 4 + 5,
|
|
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;
|
|
} noptypes[] = {
|
|
{ X86_FEATURE_K8, k8_nops },
|
|
{ X86_FEATURE_K7, k7_nops },
|
|
{ -1, NULL }
|
|
};
|
|
|
|
static unsigned char** find_nop_table(void)
|
|
{
|
|
unsigned char **noptable = intel_nops;
|
|
int i;
|
|
|
|
for (i = 0; noptypes[i].cpuid >= 0; i++) {
|
|
if (boot_cpu_has(noptypes[i].cpuid)) {
|
|
noptable = noptypes[i].noptable;
|
|
break;
|
|
}
|
|
}
|
|
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
|
|
APs have less capabilities than the boot processor are not handled.
|
|
Tough. Make sure you disable such features by hand. */
|
|
|
|
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);
|
|
for (a = start; a < end; a++) {
|
|
BUG_ON(a->replacementlen > a->instrlen);
|
|
if (!boot_cpu_has(a->cpuid))
|
|
continue;
|
|
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) {
|
|
k = diff;
|
|
if (k > ASM_NOP_MAX)
|
|
k = ASM_NOP_MAX;
|
|
memcpy(a->instr + i, noptable[k], k);
|
|
}
|
|
}
|
|
}
|
|
|
|
#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;
|
|
|
|
for (ptr = start; ptr < end; ptr++) {
|
|
if (*ptr < text)
|
|
continue;
|
|
if (*ptr > text_end)
|
|
continue;
|
|
**ptr = 0xf0; /* lock prefix */
|
|
};
|
|
}
|
|
|
|
static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
|
|
{
|
|
unsigned char **noptable = find_nop_table();
|
|
u8 **ptr;
|
|
|
|
for (ptr = start; ptr < end; ptr++) {
|
|
if (*ptr < text)
|
|
continue;
|
|
if (*ptr > text_end)
|
|
continue;
|
|
**ptr = noptable[1][0];
|
|
};
|
|
}
|
|
|
|
struct smp_alt_module {
|
|
/* what is this ??? */
|
|
struct module *mod;
|
|
char *name;
|
|
|
|
/* ptrs to lock prefixes */
|
|
u8 **locks;
|
|
u8 **locks_end;
|
|
|
|
/* .text segment, needed to avoid patching init code ;) */
|
|
u8 *text;
|
|
u8 *text_end;
|
|
|
|
struct list_head next;
|
|
};
|
|
static LIST_HEAD(smp_alt_modules);
|
|
static DEFINE_SPINLOCK(smp_alt);
|
|
|
|
void alternatives_smp_module_add(struct module *mod, char *name,
|
|
void *locks, void *locks_end,
|
|
void *text, void *text_end)
|
|
{
|
|
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,
|
|
text, text_end);
|
|
return;
|
|
}
|
|
|
|
smp = kzalloc(sizeof(*smp), GFP_KERNEL);
|
|
if (NULL == smp)
|
|
return; /* we'll run the (safe but slow) SMP code then ... */
|
|
|
|
smp->mod = mod;
|
|
smp->name = name;
|
|
smp->locks = locks;
|
|
smp->locks_end = locks_end;
|
|
smp->text = text;
|
|
smp->text_end = text_end;
|
|
DPRINTK("%s: locks %p -> %p, text %p -> %p, name %s\n",
|
|
__FUNCTION__, smp->locks, smp->locks_end,
|
|
smp->text, smp->text_end, smp->name);
|
|
|
|
spin_lock_irqsave(&smp_alt, flags);
|
|
list_add_tail(&smp->next, &smp_alt_modules);
|
|
if (boot_cpu_has(X86_FEATURE_UP))
|
|
alternatives_smp_unlock(smp->locks, smp->locks_end,
|
|
smp->text, smp->text_end);
|
|
spin_unlock_irqrestore(&smp_alt, flags);
|
|
}
|
|
|
|
void alternatives_smp_module_del(struct module *mod)
|
|
{
|
|
struct smp_alt_module *item;
|
|
unsigned long flags;
|
|
|
|
if (no_replacement || smp_alt_once)
|
|
return;
|
|
|
|
spin_lock_irqsave(&smp_alt, flags);
|
|
list_for_each_entry(item, &smp_alt_modules, next) {
|
|
if (mod != item->mod)
|
|
continue;
|
|
list_del(&item->next);
|
|
spin_unlock_irqrestore(&smp_alt, flags);
|
|
DPRINTK("%s: %s\n", __FUNCTION__, item->name);
|
|
kfree(item);
|
|
return;
|
|
}
|
|
spin_unlock_irqrestore(&smp_alt, flags);
|
|
}
|
|
|
|
void alternatives_smp_switch(int smp)
|
|
{
|
|
struct smp_alt_module *mod;
|
|
unsigned long flags;
|
|
|
|
#ifdef CONFIG_LOCKDEP
|
|
/*
|
|
* A not yet fixed binutils section handling bug prevents
|
|
* alternatives-replacement from working reliably, so turn
|
|
* it off:
|
|
*/
|
|
printk("lockdep: not fixing up alternatives.\n");
|
|
return;
|
|
#endif
|
|
|
|
if (no_replacement || smp_alt_once)
|
|
return;
|
|
BUG_ON(!smp && (num_online_cpus() > 1));
|
|
|
|
spin_lock_irqsave(&smp_alt, flags);
|
|
if (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);
|
|
} else {
|
|
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);
|
|
}
|
|
spin_unlock_irqrestore(&smp_alt, flags);
|
|
}
|
|
|
|
#endif
|
|
|
|
void __init alternative_instructions(void)
|
|
{
|
|
unsigned long flags;
|
|
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;
|
|
}
|
|
|
|
local_irq_save(flags);
|
|
apply_alternatives(__alt_instructions, __alt_instructions_end);
|
|
|
|
/* switch to patch-once-at-boottime-only mode and free the
|
|
* tables in case we know the number of CPUs will never ever
|
|
* change */
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
if (num_possible_cpus() < 2)
|
|
smp_alt_once = 1;
|
|
#else
|
|
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");
|
|
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);
|
|
} 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
|
|
local_irq_restore(flags);
|
|
}
|