diff options
Diffstat (limited to 'arch/i386')
| -rw-r--r-- | arch/i386/kernel/alternative.c | 5 | ||||
| -rw-r--r-- | arch/i386/kernel/paravirt.c | 154 |
2 files changed, 132 insertions, 27 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c index dae3ded9041..c5d037c6095 100644 --- a/arch/i386/kernel/alternative.c +++ b/arch/i386/kernel/alternative.c @@ -336,11 +336,14 @@ void apply_paravirt(struct paravirt_patch_site *start, used = paravirt_ops.patch(p->instrtype, p->clobbers, p->instr, p->len); + 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_site __start_parainstructions[], diff --git a/arch/i386/kernel/paravirt.c b/arch/i386/kernel/paravirt.c index f2982832d3b..b0ed163e6f7 100644 --- a/arch/i386/kernel/paravirt.c +++ b/arch/i386/kernel/paravirt.c @@ -54,40 +54,142 @@ char *memory_setup(void) #define DEF_NATIVE(name, code) \ extern const char start_##name[], end_##name[]; \ asm("start_" #name ": " code "; end_" #name ":") -DEF_NATIVE(cli, "cli"); -DEF_NATIVE(sti, "sti"); -DEF_NATIVE(popf, "push %eax; popf"); -DEF_NATIVE(pushf, "pushf; pop %eax"); + +DEF_NATIVE(irq_disable, "cli"); +DEF_NATIVE(irq_enable, "sti"); +DEF_NATIVE(restore_fl, "push %eax; popf"); +DEF_NATIVE(save_fl, "pushf; pop %eax"); DEF_NATIVE(iret, "iret"); -DEF_NATIVE(sti_sysexit, "sti; sysexit"); +DEF_NATIVE(irq_enable_sysexit, "sti; sysexit"); +DEF_NATIVE(read_cr2, "mov %cr2, %eax"); +DEF_NATIVE(write_cr3, "mov %eax, %cr3"); +DEF_NATIVE(read_cr3, "mov %cr3, %eax"); +DEF_NATIVE(clts, "clts"); +DEF_NATIVE(read_tsc, "rdtsc"); -static const struct native_insns -{ - const char *start, *end; -} native_insns[] = { - [PARAVIRT_PATCH(irq_disable)] = { start_cli, end_cli }, - [PARAVIRT_PATCH(irq_enable)] = { start_sti, end_sti }, - [PARAVIRT_PATCH(restore_fl)] = { start_popf, end_popf }, - [PARAVIRT_PATCH(save_fl)] = { start_pushf, end_pushf }, - [PARAVIRT_PATCH(iret)] = { start_iret, end_iret }, - [PARAVIRT_PATCH(irq_enable_sysexit)] = { start_sti_sysexit, end_sti_sysexit }, -}; +DEF_NATIVE(ud2a, "ud2a"); static unsigned native_patch(u8 type, u16 clobbers, void *insns, unsigned len) { - unsigned int insn_len; + const unsigned char *start, *end; + unsigned ret; + + switch(type) { +#define SITE(x) case PARAVIRT_PATCH(x): start = start_##x; end = end_##x; goto patch_site + SITE(irq_disable); + SITE(irq_enable); + SITE(restore_fl); + SITE(save_fl); + SITE(iret); + SITE(irq_enable_sysexit); + SITE(read_cr2); + SITE(read_cr3); + SITE(write_cr3); + SITE(clts); + SITE(read_tsc); +#undef SITE + + patch_site: + ret = paravirt_patch_insns(insns, len, start, end); + break; + + case PARAVIRT_PATCH(make_pgd): + case PARAVIRT_PATCH(make_pte): + case PARAVIRT_PATCH(pgd_val): + case PARAVIRT_PATCH(pte_val): +#ifdef CONFIG_X86_PAE + case PARAVIRT_PATCH(make_pmd): + case PARAVIRT_PATCH(pmd_val): +#endif + /* These functions end up returning exactly what + they're passed, in the same registers. */ + ret = paravirt_patch_nop(); + break; + + default: + ret = paravirt_patch_default(type, clobbers, insns, len); + break; + } + + return ret; +} + +unsigned paravirt_patch_nop(void) +{ + return 0; +} + +unsigned paravirt_patch_ignore(unsigned len) +{ + return len; +} + +unsigned paravirt_patch_call(void *target, u16 tgt_clobbers, + void *site, u16 site_clobbers, + unsigned len) +{ + unsigned char *call = site; + unsigned long delta = (unsigned long)target - (unsigned long)(call+5); + + if (tgt_clobbers & ~site_clobbers) + return len; /* target would clobber too much for this site */ + if (len < 5) + return len; /* call too long for patch site */ + + *call++ = 0xe8; /* call */ + *(unsigned long *)call = delta; + + return 5; +} + +unsigned paravirt_patch_jmp(void *target, void *site, unsigned len) +{ + unsigned char *jmp = site; + unsigned long delta = (unsigned long)target - (unsigned long)(jmp+5); - /* Don't touch it if we don't have a replacement */ - if (type >= ARRAY_SIZE(native_insns) || !native_insns[type].start) - return len; + if (len < 5) + return len; /* call too long for patch site */ - insn_len = native_insns[type].end - native_insns[type].start; + *jmp++ = 0xe9; /* jmp */ + *(unsigned long *)jmp = delta; + + return 5; +} + +unsigned paravirt_patch_default(u8 type, u16 clobbers, void *site, unsigned len) +{ + void *opfunc = *((void **)¶virt_ops + type); + unsigned ret; + + if (opfunc == NULL) + /* If there's no function, patch it with a ud2a (BUG) */ + ret = paravirt_patch_insns(site, len, start_ud2a, end_ud2a); + else if (opfunc == paravirt_nop) + /* If the operation is a nop, then nop the callsite */ + ret = paravirt_patch_nop(); + else if (type == PARAVIRT_PATCH(iret) || + type == PARAVIRT_PATCH(irq_enable_sysexit)) + /* If operation requires a jmp, then jmp */ + ret = paravirt_patch_jmp(opfunc, site, len); + else + /* Otherwise call the function; assume target could + clobber any caller-save reg */ + ret = paravirt_patch_call(opfunc, CLBR_ANY, + site, clobbers, len); + + return ret; +} + +unsigned paravirt_patch_insns(void *site, unsigned len, + const char *start, const char *end) +{ + unsigned insn_len = end - start; - /* Similarly if we can't fit replacement. */ - if (len < insn_len) - return len; + if (insn_len > len || start == NULL) + insn_len = len; + else + memcpy(site, start, insn_len); - memcpy(insns, native_insns[type].start, insn_len); return insn_len; } @@ -110,7 +212,7 @@ static void native_flush_tlb_global(void) __native_flush_tlb_global(); } -static void native_flush_tlb_single(u32 addr) +static void native_flush_tlb_single(unsigned long addr) { __native_flush_tlb_single(addr); } |