diff options
Diffstat (limited to 'arch/i386/kernel/alternative.c')
| -rw-r--r-- | arch/i386/kernel/alternative.c | 450 |
1 files changed, 0 insertions, 450 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c deleted file mode 100644 index bd72d94e713..00000000000 --- a/arch/i386/kernel/alternative.c +++ /dev/null @@ -1,450 +0,0 @@ -#include <linux/module.h> -#include <linux/sched.h> -#include <linux/spinlock.h> -#include <linux/list.h> -#include <linux/kprobes.h> -#include <linux/mm.h> -#include <linux/vmalloc.h> -#include <asm/alternative.h> -#include <asm/sections.h> -#include <asm/pgtable.h> -#include <asm/mce.h> -#include <asm/nmi.h> - -#define MAX_PATCH_LEN (255-1) - -#ifdef CONFIG_HOTPLUG_CPU -static int smp_alt_once; - -static int __init bootonly(char *str) -{ - smp_alt_once = 1; - return 1; -} -__setup("smp-alt-boot", bootonly); -#else -#define smp_alt_once 1 -#endif - -static int debug_alternative; - -static int __init debug_alt(char *str) -{ - debug_alternative = 1; - return 1; -} -__setup("debug-alternative", debug_alt); - -static int noreplace_smp; - -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) - -#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 */ - -/* Use this to add nops to a buffer, then text_poke the whole buffer. */ -static void add_nops(void *insns, unsigned int len) -{ - unsigned char **noptable = find_nop_table(); - - while (len > 0) { - unsigned int noplen = len; - if (noplen > ASM_NOP_MAX) - noplen = ASM_NOP_MAX; - memcpy(insns, noptable[noplen], noplen); - insns += noplen; - len -= noplen; - } -} - -extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; -extern u8 *__smp_locks[], *__smp_locks_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) -{ - struct alt_instr *a; - char insnbuf[MAX_PATCH_LEN]; - - DPRINTK("%s: alt table %p -> %p\n", __FUNCTION__, start, end); - for (a = start; a < end; a++) { - u8 *instr = a->instr; - BUG_ON(a->replacementlen > a->instrlen); - BUG_ON(a->instrlen > sizeof(insnbuf)); - if (!boot_cpu_has(a->cpuid)) - continue; -#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(insnbuf, a->replacement, a->replacementlen); - add_nops(insnbuf + a->replacementlen, - a->instrlen - a->replacementlen); - text_poke(instr, insnbuf, a->instrlen); - } -} - -#ifdef CONFIG_SMP - -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; - text_poke(*ptr, ((unsigned char []){0xf0}), 1); /* add lock prefix */ - }; -} - -static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end) -{ - u8 **ptr; - char insn[1]; - - if (noreplace_smp) - return; - - add_nops(insn, 1); - for (ptr = start; ptr < end; ptr++) { - if (*ptr < text) - continue; - if (*ptr > text_end) - continue; - text_poke(*ptr, insn, 1); - }; -} - -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 (noreplace_smp) - 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 (smp_alt_once || noreplace_smp) - 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 (noreplace_smp || 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); - 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); - 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 - -#ifdef CONFIG_PARAVIRT -void apply_paravirt(struct paravirt_patch_site *start, - struct paravirt_patch_site *end) -{ - struct paravirt_patch_site *p; - char insnbuf[MAX_PATCH_LEN]; - - if (noreplace_paravirt) - return; - - for (p = start; p < end; p++) { - unsigned int used; - - BUG_ON(p->len > MAX_PATCH_LEN); - /* prep the buffer with the original instructions */ - memcpy(insnbuf, p->instr, p->len); - used = paravirt_ops.patch(p->instrtype, p->clobbers, insnbuf, - (unsigned long)p->instr, p->len); - - BUG_ON(used > p->len); - - /* Pad the rest with nops */ - add_nops(insnbuf + used, p->len - used); - text_poke(p->instr, insnbuf, p->len); - } -} -extern struct paravirt_patch_site __start_parainstructions[], - __stop_parainstructions[]; -#endif /* CONFIG_PARAVIRT */ - -void __init alternative_instructions(void) -{ - unsigned long flags; - - /* The patching is not fully atomic, so try to avoid local interruptions - that might execute the to be patched code. - Other CPUs are not running. */ - stop_nmi(); -#ifdef CONFIG_X86_MCE - stop_mce(); -#endif - - 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; -#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); - alternatives_smp_unlock(__smp_locks, __smp_locks_end, - _text, _etext); - } - free_init_pages("SMP alternatives", - (unsigned long)__smp_locks, - (unsigned long)__smp_locks_end); - } else { - alternatives_smp_module_add(NULL, "core kernel", - __smp_locks, __smp_locks_end, - _text, _etext); - alternatives_smp_switch(0); - } -#endif - apply_paravirt(__parainstructions, __parainstructions_end); - local_irq_restore(flags); - - restart_nmi(); -#ifdef CONFIG_X86_MCE - restart_mce(); -#endif -} - -/* - * Warning: - * When you use this code to patch more than one byte of an instruction - * you need to make sure that other CPUs cannot execute this code in parallel. - * Also no thread must be currently preempted in the middle of these instructions. - * And on the local CPU you need to be protected again NMI or MCE handlers - * seeing an inconsistent instruction while you patch. - */ -void __kprobes text_poke(void *addr, unsigned char *opcode, int len) -{ - memcpy(addr, opcode, len); - sync_core(); - /* Could also do a CLFLUSH here to speed up CPU recovery; but - that causes hangs on some VIA CPUs. */ -} |