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arch/x86/kernel/alternative.c
18.7 KB
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#include <linux/module.h> |
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#include <linux/sched.h> |
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#include <linux/mutex.h> |
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#include <linux/list.h> |
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#include <linux/stringify.h> |
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#include <linux/kprobes.h> #include <linux/mm.h> #include <linux/vmalloc.h> |
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#include <linux/memory.h> |
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#include <linux/stop_machine.h> |
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#include <linux/slab.h> |
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#include <asm/alternative.h> #include <asm/sections.h> |
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#include <asm/pgtable.h> |
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#include <asm/mce.h> #include <asm/nmi.h> |
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#include <asm/cacheflush.h> |
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#include <asm/tlbflush.h> |
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#include <asm/io.h> |
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#include <asm/fixmap.h> |
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|
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#define MAX_PATCH_LEN (255-1) |
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#ifdef CONFIG_HOTPLUG_CPU static int smp_alt_once; |
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|
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static int __init bootonly(char *str) { smp_alt_once = 1; return 1; } |
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__setup("smp-alt-boot", bootonly); |
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#else #define smp_alt_once 1 #endif |
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static int __initdata_or_module debug_alternative; |
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static int __init debug_alt(char *str) { debug_alternative = 1; return 1; } |
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__setup("debug-alternative", debug_alt); |
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static int noreplace_smp; |
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static int __init setup_noreplace_smp(char *str) { noreplace_smp = 1; return 1; } __setup("noreplace-smp", setup_noreplace_smp); |
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#ifdef CONFIG_PARAVIRT |
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static int __initdata_or_module noreplace_paravirt = 0; |
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static int __init setup_noreplace_paravirt(char *str) { noreplace_paravirt = 1; return 1; } __setup("noreplace-paravirt", setup_noreplace_paravirt); #endif |
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#define DPRINTK(fmt, args...) if (debug_alternative) \ printk(KERN_DEBUG fmt, args) |
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/* * Each GENERIC_NOPX is of X bytes, and defined as an array of bytes * that correspond to that nop. Getting from one nop to the next, we * add to the array the offset that is equal to the sum of all sizes of * nops preceding the one we are after. * * Note: The GENERIC_NOP5_ATOMIC is at the end, as it breaks the * nice symmetry of sizes of the previous nops. */ |
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#if defined(GENERIC_NOP1) && !defined(CONFIG_X86_64) |
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static const unsigned char intelnops[] = { GENERIC_NOP1, GENERIC_NOP2, GENERIC_NOP3, GENERIC_NOP4, GENERIC_NOP5, GENERIC_NOP6, GENERIC_NOP7, GENERIC_NOP8, GENERIC_NOP5_ATOMIC }; static const unsigned char * const intel_nops[ASM_NOP_MAX+2] = { |
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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, |
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intelnops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
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}; |
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#endif #ifdef K8_NOP1 |
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static const unsigned char k8nops[] = { K8_NOP1, K8_NOP2, K8_NOP3, K8_NOP4, K8_NOP5, K8_NOP6, K8_NOP7, K8_NOP8, K8_NOP5_ATOMIC }; static const unsigned char * const k8_nops[ASM_NOP_MAX+2] = { |
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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, |
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k8nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
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}; |
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#endif |
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#if defined(K7_NOP1) && !defined(CONFIG_X86_64) |
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static const unsigned char k7nops[] = { K7_NOP1, K7_NOP2, K7_NOP3, K7_NOP4, K7_NOP5, K7_NOP6, K7_NOP7, K7_NOP8, K7_NOP5_ATOMIC }; static const unsigned char * const k7_nops[ASM_NOP_MAX+2] = { |
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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, |
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k7nops + 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8, |
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}; |
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#endif |
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#ifdef P6_NOP1 |
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static const unsigned char __initconst_or_module p6nops[] = { P6_NOP1, P6_NOP2, P6_NOP3, P6_NOP4, P6_NOP5, P6_NOP6, P6_NOP7, P6_NOP8, P6_NOP5_ATOMIC }; static const unsigned char * const p6_nops[ASM_NOP_MAX+2] = { |
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NULL, p6nops, p6nops + 1, p6nops + 1 + 2, p6nops + 1 + 2 + 3, p6nops + 1 + 2 + 3 + 4, p6nops + 1 + 2 + 3 + 4 + 5, p6nops + 1 + 2 + 3 + 4 + 5 + 6, p6nops + 1 + 2 + 3 + 4 + 5 + 6 + 7, |
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}; #endif |
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/* Initialize these to a safe default */ |
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#ifdef CONFIG_X86_64 |
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const unsigned char * const *ideal_nops = p6_nops; #else const unsigned char * const *ideal_nops = intel_nops; #endif |
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|
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void __init arch_init_ideal_nops(void) |
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{ |
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switch (boot_cpu_data.x86_vendor) { case X86_VENDOR_INTEL: |
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/* * Due to a decoder implementation quirk, some * specific Intel CPUs actually perform better with * the "k8_nops" than with the SDM-recommended NOPs. */ if (boot_cpu_data.x86 == 6 && boot_cpu_data.x86_model >= 0x0f && boot_cpu_data.x86_model != 0x1c && boot_cpu_data.x86_model != 0x26 && boot_cpu_data.x86_model != 0x27 && boot_cpu_data.x86_model < 0x30) { ideal_nops = k8_nops; } else if (boot_cpu_has(X86_FEATURE_NOPL)) { |
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ideal_nops = p6_nops; } else { #ifdef CONFIG_X86_64 ideal_nops = k8_nops; #else ideal_nops = intel_nops; #endif } |
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|
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default: #ifdef CONFIG_X86_64 ideal_nops = k8_nops; #else if (boot_cpu_has(X86_FEATURE_K8)) ideal_nops = k8_nops; else if (boot_cpu_has(X86_FEATURE_K7)) ideal_nops = k7_nops; else ideal_nops = intel_nops; #endif } |
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} |
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/* Use this to add nops to a buffer, then text_poke the whole buffer. */ |
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static void __init_or_module add_nops(void *insns, unsigned int len) |
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{ |
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while (len > 0) { unsigned int noplen = len; if (noplen > ASM_NOP_MAX) noplen = ASM_NOP_MAX; |
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memcpy(insns, ideal_nops[noplen], noplen); |
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insns += noplen; len -= noplen; } } |
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extern struct alt_instr __alt_instructions[], __alt_instructions_end[]; |
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extern s32 __smp_locks[], __smp_locks_end[]; |
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void *text_poke_early(void *addr, const void *opcode, size_t len); |
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|
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/* Replace instructions with better alternatives for this CPU type. This runs before SMP is initialized to avoid SMP problems with |
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self modifying code. This implies that asymmetric systems where |
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APs have less capabilities than the boot processor are not handled. Tough. Make sure you disable such features by hand. */ |
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void __init_or_module apply_alternatives(struct alt_instr *start, struct alt_instr *end) |
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{ |
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struct alt_instr *a; |
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u8 *instr, *replacement; |
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u8 insnbuf[MAX_PATCH_LEN]; |
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|
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DPRINTK("%s: alt table %p -> %p ", __func__, start, end); |
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/* * The scan order should be from start to end. A later scanned * alternative code can overwrite a previous scanned alternative code. * Some kernel functions (e.g. memcpy, memset, etc) use this order to * patch code. * * So be careful if you want to change the scan order to any other * order. */ |
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for (a = start; a < end; a++) { |
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instr = (u8 *)&a->instr_offset + a->instr_offset; replacement = (u8 *)&a->repl_offset + a->repl_offset; |
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BUG_ON(a->replacementlen > a->instrlen); |
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BUG_ON(a->instrlen > sizeof(insnbuf)); |
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BUG_ON(a->cpuid >= NCAPINTS*32); |
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if (!boot_cpu_has(a->cpuid)) continue; |
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memcpy(insnbuf, replacement, a->replacementlen); /* 0xe8 is a relative jump; fix the offset. */ if (*insnbuf == 0xe8 && a->replacementlen == 5) *(s32 *)(insnbuf + 1) += replacement - instr; add_nops(insnbuf + a->replacementlen, a->instrlen - a->replacementlen); |
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text_poke_early(instr, insnbuf, a->instrlen); |
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} } |
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#ifdef CONFIG_SMP |
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static void alternatives_smp_lock(const s32 *start, const s32 *end, u8 *text, u8 *text_end) |
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{ |
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const s32 *poff; |
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|
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mutex_lock(&text_mutex); |
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for (poff = start; poff < end; poff++) { u8 *ptr = (u8 *)poff + *poff; if (!*poff || ptr < text || ptr >= text_end) |
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continue; |
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/* turn DS segment override prefix into lock prefix */ |
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if (*ptr == 0x3e) text_poke(ptr, ((unsigned char []){0xf0}), 1); |
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}; |
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mutex_unlock(&text_mutex); |
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} |
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static void alternatives_smp_unlock(const s32 *start, const s32 *end, u8 *text, u8 *text_end) |
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{ |
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const s32 *poff; |
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|
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if (noreplace_smp) return; |
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mutex_lock(&text_mutex); |
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for (poff = start; poff < end; poff++) { u8 *ptr = (u8 *)poff + *poff; if (!*poff || ptr < text || ptr >= text_end) |
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continue; |
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/* turn lock prefix into DS segment override prefix */ |
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if (*ptr == 0xf0) text_poke(ptr, ((unsigned char []){0x3E}), 1); |
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}; |
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mutex_unlock(&text_mutex); |
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} struct smp_alt_module { /* what is this ??? */ struct module *mod; char *name; /* ptrs to lock prefixes */ |
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const s32 *locks; const s32 *locks_end; |
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/* .text segment, needed to avoid patching init code ;) */ u8 *text; u8 *text_end; struct list_head next; }; static LIST_HEAD(smp_alt_modules); |
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static DEFINE_MUTEX(smp_alt); |
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static int smp_mode = 1; /* protected by smp_alt */ |
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|
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void __init_or_module alternatives_smp_module_add(struct module *mod, char *name, void *locks, void *locks_end, void *text, void *text_end) |
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{ struct smp_alt_module *smp; |
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|
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if (noreplace_smp) return; |
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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 ", |
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__func__, smp->locks, smp->locks_end, |
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smp->text, smp->text_end, smp->name); |
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mutex_lock(&smp_alt); |
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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); |
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mutex_unlock(&smp_alt); |
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} |
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void __init_or_module alternatives_smp_module_del(struct module *mod) |
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{ struct smp_alt_module *item; |
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|
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if (smp_alt_once || noreplace_smp) |
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return; |
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mutex_lock(&smp_alt); |
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list_for_each_entry(item, &smp_alt_modules, next) { if (mod != item->mod) continue; list_del(&item->next); |
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mutex_unlock(&smp_alt); |
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DPRINTK("%s: %s ", __func__, item->name); |
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kfree(item); return; } |
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mutex_unlock(&smp_alt); |
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} |
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bool skip_smp_alternatives; |
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void alternatives_smp_switch(int smp) { struct smp_alt_module *mod; |
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|
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#ifdef CONFIG_LOCKDEP /* |
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* Older binutils section handling bug prevented * alternatives-replacement from working reliably. * * If this still occurs then you should see a hang * or crash shortly after this line: |
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*/ |
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printk("lockdep: fixing up alternatives. "); |
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#endif |
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if (noreplace_smp || smp_alt_once || skip_smp_alternatives) |
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return; BUG_ON(!smp && (num_online_cpus() > 1)); |
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mutex_lock(&smp_alt); |
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/* * Avoid unnecessary switches because it forces JIT based VMs to * throw away all cached translations, which can be quite costly. */ if (smp == smp_mode) { /* nothing */ } else if (smp) { |
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printk(KERN_INFO "SMP alternatives: switching to SMP code "); |
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clear_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); clear_cpu_cap(&cpu_data(0), X86_FEATURE_UP); |
9a0b5817a [PATCH] x86: SMP ... |
431 432 433 434 435 436 |
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 "); |
53756d372 x86: add set/clea... |
437 438 |
set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); set_cpu_cap(&cpu_data(0), X86_FEATURE_UP); |
9a0b5817a [PATCH] x86: SMP ... |
439 440 441 442 |
list_for_each_entry(mod, &smp_alt_modules, next) alternatives_smp_unlock(mod->locks, mod->locks_end, mod->text, mod->text_end); } |
ca74a6f84 x86: optimize loc... |
443 |
smp_mode = smp; |
2f1dafe50 x86: fix SMP alte... |
444 |
mutex_unlock(&smp_alt); |
9a0b5817a [PATCH] x86: SMP ... |
445 |
} |
2cfa19780 ftrace/alternativ... |
446 447 448 449 |
/* Return 1 if the address range is reserved for smp-alternatives */ int alternatives_text_reserved(void *start, void *end) { struct smp_alt_module *mod; |
5967ed87a x86-64: Reduce SM... |
450 |
const s32 *poff; |
076dc4a65 x86/alternatives:... |
451 452 |
u8 *text_start = start; u8 *text_end = end; |
2cfa19780 ftrace/alternativ... |
453 454 |
list_for_each_entry(mod, &smp_alt_modules, next) { |
076dc4a65 x86/alternatives:... |
455 |
if (mod->text > text_end || mod->text_end < text_start) |
2cfa19780 ftrace/alternativ... |
456 |
continue; |
5967ed87a x86-64: Reduce SM... |
457 458 459 460 |
for (poff = mod->locks; poff < mod->locks_end; poff++) { const u8 *ptr = (const u8 *)poff + *poff; if (text_start <= ptr && text_end > ptr) |
2cfa19780 ftrace/alternativ... |
461 |
return 1; |
5967ed87a x86-64: Reduce SM... |
462 |
} |
2cfa19780 ftrace/alternativ... |
463 464 465 466 |
} return 0; } |
8ec4d41f8 [PATCH] SMP alter... |
467 |
#endif |
139ec7c41 [PATCH] paravirt:... |
468 |
#ifdef CONFIG_PARAVIRT |
8b5a10fc6 x86: properly ann... |
469 470 |
void __init_or_module apply_paravirt(struct paravirt_patch_site *start, struct paravirt_patch_site *end) |
139ec7c41 [PATCH] paravirt:... |
471 |
{ |
98de032b6 [PATCH] i386: PAR... |
472 |
struct paravirt_patch_site *p; |
ab144f5ec i386: Make patchi... |
473 |
char insnbuf[MAX_PATCH_LEN]; |
139ec7c41 [PATCH] paravirt:... |
474 |
|
959b4fdfe [PATCH] i386: PAR... |
475 476 |
if (noreplace_paravirt) return; |
139ec7c41 [PATCH] paravirt:... |
477 478 |
for (p = start; p < end; p++) { unsigned int used; |
ab144f5ec i386: Make patchi... |
479 |
BUG_ON(p->len > MAX_PATCH_LEN); |
d34fda4a8 x86: properly ini... |
480 481 |
/* prep the buffer with the original instructions */ memcpy(insnbuf, p->instr, p->len); |
93b1eab3d paravirt: refacto... |
482 483 |
used = pv_init_ops.patch(p->instrtype, p->clobbers, insnbuf, (unsigned long)p->instr, p->len); |
7f63c41c6 [PATCH] i386: PAR... |
484 |
|
63f70270c [PATCH] i386: PAR... |
485 |
BUG_ON(used > p->len); |
139ec7c41 [PATCH] paravirt:... |
486 |
/* Pad the rest with nops */ |
ab144f5ec i386: Make patchi... |
487 |
add_nops(insnbuf + used, p->len - used); |
e587cadd8 x86: enhance DEBU... |
488 |
text_poke_early(p->instr, insnbuf, p->len); |
139ec7c41 [PATCH] paravirt:... |
489 |
} |
139ec7c41 [PATCH] paravirt:... |
490 |
} |
98de032b6 [PATCH] i386: PAR... |
491 |
extern struct paravirt_patch_site __start_parainstructions[], |
139ec7c41 [PATCH] paravirt:... |
492 493 |
__stop_parainstructions[]; #endif /* CONFIG_PARAVIRT */ |
9a0b5817a [PATCH] x86: SMP ... |
494 495 |
void __init alternative_instructions(void) { |
8f4e956b3 x86: Stop MCEs an... |
496 497 498 499 |
/* 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(); |
123aa76ec x86, mce: don't d... |
500 501 502 503 504 505 506 507 508 509 510 |
/* * Don't stop machine check exceptions while patching. * MCEs only happen when something got corrupted and in this * case we must do something about the corruption. * Ignoring it is worse than a unlikely patching race. * Also machine checks tend to be broadcast and if one CPU * goes into machine check the others follow quickly, so we don't * expect a machine check to cause undue problems during to code * patching. */ |
8f4e956b3 x86: Stop MCEs an... |
511 |
|
9a0b5817a [PATCH] x86: SMP ... |
512 513 514 515 516 517 518 519 |
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; |
9a0b5817a [PATCH] x86: SMP ... |
520 |
#endif |
8ec4d41f8 [PATCH] SMP alter... |
521 |
#ifdef CONFIG_SMP |
9a0b5817a [PATCH] x86: SMP ... |
522 523 524 525 |
if (smp_alt_once) { if (1 == num_possible_cpus()) { printk(KERN_INFO "SMP alternatives: switching to UP code "); |
53756d372 x86: add set/clea... |
526 527 |
set_cpu_cap(&boot_cpu_data, X86_FEATURE_UP); set_cpu_cap(&cpu_data(0), X86_FEATURE_UP); |
9a0b5817a [PATCH] x86: SMP ... |
528 529 530 |
alternatives_smp_unlock(__smp_locks, __smp_locks_end, _text, _etext); } |
9a0b5817a [PATCH] x86: SMP ... |
531 |
} else { |
9a0b5817a [PATCH] x86: SMP ... |
532 533 534 |
alternatives_smp_module_add(NULL, "core kernel", __smp_locks, __smp_locks_end, _text, _etext); |
ca74a6f84 x86: optimize loc... |
535 536 |
/* Only switch to UP mode if we don't immediately boot others */ |
649c6653f x86: improve UP k... |
537 |
if (num_present_cpus() == 1 || setup_max_cpus <= 1) |
ca74a6f84 x86: optimize loc... |
538 |
alternatives_smp_switch(0); |
9a0b5817a [PATCH] x86: SMP ... |
539 |
} |
8ec4d41f8 [PATCH] SMP alter... |
540 |
#endif |
441d40dca [PATCH] x86: PARA... |
541 |
apply_paravirt(__parainstructions, __parainstructions_end); |
8f4e956b3 x86: Stop MCEs an... |
542 |
|
f68fd5f48 x86: call free_in... |
543 544 545 546 |
if (smp_alt_once) free_init_pages("SMP alternatives", (unsigned long)__smp_locks, (unsigned long)__smp_locks_end); |
8f4e956b3 x86: Stop MCEs an... |
547 |
restart_nmi(); |
9a0b5817a [PATCH] x86: SMP ... |
548 |
} |
19d36ccdc x86: Fix alternat... |
549 |
|
e587cadd8 x86: enhance DEBU... |
550 551 552 553 554 555 |
/** * text_poke_early - Update instructions on a live kernel at boot time * @addr: address to modify * @opcode: source of the copy * @len: length to copy * |
19d36ccdc x86: Fix alternat... |
556 557 |
* 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. |
e587cadd8 x86: enhance DEBU... |
558 559 560 |
* 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. |
19d36ccdc x86: Fix alternat... |
561 |
*/ |
fa6f2cc77 jump label: Make ... |
562 |
void *__init_or_module text_poke_early(void *addr, const void *opcode, |
8b5a10fc6 x86: properly ann... |
563 |
size_t len) |
19d36ccdc x86: Fix alternat... |
564 |
{ |
e587cadd8 x86: enhance DEBU... |
565 566 |
unsigned long flags; local_irq_save(flags); |
19d36ccdc x86: Fix alternat... |
567 |
memcpy(addr, opcode, len); |
e587cadd8 x86: enhance DEBU... |
568 |
sync_core(); |
5367b6887 x86: Fix code pat... |
569 |
local_irq_restore(flags); |
e587cadd8 x86: enhance DEBU... |
570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 |
/* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ return addr; } /** * text_poke - Update instructions on a live kernel * @addr: address to modify * @opcode: source of the copy * @len: length to copy * * Only atomic text poke/set should be allowed when not doing early patching. * It means the size must be writable atomically and the address must be aligned * in a way that permits an atomic write. It also makes sure we fit on a single * page. |
78ff7fae0 x86: implement at... |
585 586 |
* * Note: Must be called under text_mutex. |
e587cadd8 x86: enhance DEBU... |
587 588 589 |
*/ void *__kprobes text_poke(void *addr, const void *opcode, size_t len) { |
78ff7fae0 x86: implement at... |
590 |
unsigned long flags; |
e587cadd8 x86: enhance DEBU... |
591 |
char *vaddr; |
b7b66baa8 x86: clean up tex... |
592 593 |
struct page *pages[2]; int i; |
e587cadd8 x86: enhance DEBU... |
594 |
|
b7b66baa8 x86: clean up tex... |
595 596 597 |
if (!core_kernel_text((unsigned long)addr)) { pages[0] = vmalloc_to_page(addr); pages[1] = vmalloc_to_page(addr + PAGE_SIZE); |
15a601eb9 x86: fix test_pok... |
598 |
} else { |
b7b66baa8 x86: clean up tex... |
599 |
pages[0] = virt_to_page(addr); |
00c6b2d5d x86: harden kerne... |
600 |
WARN_ON(!PageReserved(pages[0])); |
b7b66baa8 x86: clean up tex... |
601 |
pages[1] = virt_to_page(addr + PAGE_SIZE); |
e587cadd8 x86: enhance DEBU... |
602 |
} |
b7b66baa8 x86: clean up tex... |
603 |
BUG_ON(!pages[0]); |
7cf494270 x86: expand irq-o... |
604 |
local_irq_save(flags); |
78ff7fae0 x86: implement at... |
605 606 607 608 |
set_fixmap(FIX_TEXT_POKE0, page_to_phys(pages[0])); if (pages[1]) set_fixmap(FIX_TEXT_POKE1, page_to_phys(pages[1])); vaddr = (char *)fix_to_virt(FIX_TEXT_POKE0); |
b7b66baa8 x86: clean up tex... |
609 |
memcpy(&vaddr[(unsigned long)addr & ~PAGE_MASK], opcode, len); |
78ff7fae0 x86: implement at... |
610 611 612 613 |
clear_fixmap(FIX_TEXT_POKE0); if (pages[1]) clear_fixmap(FIX_TEXT_POKE1); local_flush_tlb(); |
19d36ccdc x86: Fix alternat... |
614 |
sync_core(); |
a534b6791 x86_64: Remove CL... |
615 616 |
/* Could also do a CLFLUSH here to speed up CPU recovery; but that causes hangs on some VIA CPUs. */ |
b7b66baa8 x86: clean up tex... |
617 618 |
for (i = 0; i < len; i++) BUG_ON(((char *)addr)[i] != ((char *)opcode)[i]); |
7cf494270 x86: expand irq-o... |
619 |
local_irq_restore(flags); |
e587cadd8 x86: enhance DEBU... |
620 |
return addr; |
19d36ccdc x86: Fix alternat... |
621 |
} |
3d55cc8a0 x86: Add text_pok... |
622 623 624 625 626 627 628 629 630 |
/* * Cross-modifying kernel text with stop_machine(). * This code originally comes from immediate value. */ static atomic_t stop_machine_first; static int wrote_text; struct text_poke_params { |
7deb18dcf x86: Introduce te... |
631 632 |
struct text_poke_param *params; int nparams; |
3d55cc8a0 x86: Add text_pok... |
633 634 635 636 637 |
}; static int __kprobes stop_machine_text_poke(void *data) { struct text_poke_params *tpp = data; |
7deb18dcf x86: Introduce te... |
638 639 |
struct text_poke_param *p; int i; |
3d55cc8a0 x86: Add text_pok... |
640 641 |
if (atomic_dec_and_test(&stop_machine_first)) { |
7deb18dcf x86: Introduce te... |
642 643 644 645 |
for (i = 0; i < tpp->nparams; i++) { p = &tpp->params[i]; text_poke(p->addr, p->opcode, p->len); } |
3d55cc8a0 x86: Add text_pok... |
646 647 648 649 |
smp_wmb(); /* Make sure other cpus see that this has run */ wrote_text = 1; } else { while (!wrote_text) |
e5a110166 x86: Issue at lea... |
650 651 |
cpu_relax(); smp_mb(); /* Load wrote_text before following execution */ |
3d55cc8a0 x86: Add text_pok... |
652 |
} |
7deb18dcf x86: Introduce te... |
653 654 655 656 657 |
for (i = 0; i < tpp->nparams; i++) { p = &tpp->params[i]; flush_icache_range((unsigned long)p->addr, (unsigned long)p->addr + p->len); } |
0e00f7aed x86: stop_machine... |
658 659 660 661 662 663 |
/* * Intel Archiecture Software Developer's Manual section 7.1.3 specifies * that a core serializing instruction such as "cpuid" should be * executed on _each_ core before the new instruction is made visible. */ sync_core(); |
3d55cc8a0 x86: Add text_pok... |
664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 |
return 0; } /** * text_poke_smp - Update instructions on a live kernel on SMP * @addr: address to modify * @opcode: source of the copy * @len: length to copy * * Modify multi-byte instruction by using stop_machine() on SMP. This allows * user to poke/set multi-byte text on SMP. Only non-NMI/MCE code modifying * should be allowed, since stop_machine() does _not_ protect code against * NMI and MCE. * * Note: Must be called under get_online_cpus() and text_mutex. */ void *__kprobes text_poke_smp(void *addr, const void *opcode, size_t len) { struct text_poke_params tpp; |
7deb18dcf x86: Introduce te... |
683 |
struct text_poke_param p; |
3d55cc8a0 x86: Add text_pok... |
684 |
|
7deb18dcf x86: Introduce te... |
685 686 687 688 689 |
p.addr = addr; p.opcode = opcode; p.len = len; tpp.params = &p; tpp.nparams = 1; |
3d55cc8a0 x86: Add text_pok... |
690 691 |
atomic_set(&stop_machine_first, 1); wrote_text = 0; |
3caa37519 x86: Use __stop_m... |
692 |
/* Use __stop_machine() because the caller already got online_cpus. */ |
404ba5d7b x86, alternative:... |
693 |
__stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask); |
3d55cc8a0 x86: Add text_pok... |
694 695 |
return addr; } |
7deb18dcf x86: Introduce te... |
696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 |
/** * text_poke_smp_batch - Update instructions on a live kernel on SMP * @params: an array of text_poke parameters * @n: the number of elements in params. * * Modify multi-byte instruction by using stop_machine() on SMP. Since the * stop_machine() is heavy task, it is better to aggregate text_poke requests * and do it once if possible. * * Note: Must be called under get_online_cpus() and text_mutex. */ void __kprobes text_poke_smp_batch(struct text_poke_param *params, int n) { struct text_poke_params tpp = {.params = params, .nparams = n}; atomic_set(&stop_machine_first, 1); wrote_text = 0; |
78345d2ed x86: Call stop_ma... |
713 |
__stop_machine(stop_machine_text_poke, (void *)&tpp, cpu_online_mask); |
7deb18dcf x86: Introduce te... |
714 |
} |