diff options
author | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-04-02 00:08:05 -0500 |
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committer | Dmitry Torokhov <dtor_core@ameritech.net> | 2006-04-02 00:08:05 -0500 |
commit | 95d465fd750897ab32462a6702fbfe1b122cbbc0 (patch) | |
tree | 65c38b2f11c51bb6932e44dd6c92f15b0091abfe /arch/i386/kernel/alternative.c | |
parent | 642fde17dceceb56c7ba2762733ac688666ae657 (diff) | |
parent | 683aa4012f53b2ada0f430487e05d37b0d94e90a (diff) |
Manual merge with Linus.
Conflicts:
arch/powerpc/kernel/setup-common.c
drivers/input/keyboard/hil_kbd.c
drivers/input/mouse/hil_ptr.c
Diffstat (limited to 'arch/i386/kernel/alternative.c')
-rw-r--r-- | arch/i386/kernel/alternative.c | 321 |
1 files changed, 321 insertions, 0 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c new file mode 100644 index 00000000000..5cbd6f99fb2 --- /dev/null +++ b/arch/i386/kernel/alternative.c @@ -0,0 +1,321 @@ +#include <linux/module.h> +#include <linux/spinlock.h> +#include <linux/list.h> +#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 + +/* 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[]; +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, +}; +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, +}; +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, +}; +static struct nop { + int cpuid; + unsigned char **noptable; +} noptypes[] = { + { X86_FEATURE_K8, k8_nops }, + { X86_FEATURE_K7, k7_nops }, + { -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; + int i; + + for (i = 0; noptypes[i].cpuid >= 0; i++) { + if (boot_cpu_has(noptypes[i].cpuid)) { + noptable = noptypes[i].noptable; + break; + } + } + return noptable; +} + +/* 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; + 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; + memcpy(a->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); + } + } +} + +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); + +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) +{ + struct smp_alt_module *smp; + unsigned long flags; + + 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 (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; + + if (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); +} + +void __init alternative_instructions(void) +{ + 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 + + 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); + } +} |