From d167a51877e94dda73dd656c51f363502309f713 Mon Sep 17 00:00:00 2001 From: Gerd Hoffmann Date: Mon, 26 Jun 2006 13:56:16 +0200 Subject: [PATCH] x86_64: x86_64 version of the smp alternative patch. Changes are largely identical to the i386 version: * alternative #define are moved to the new alternative.h file. * one new elf section with pointers to the lock prefixes which can be nop'ed out for non-smp. * two new elf sections simliar to the "classic" alternatives to replace SMP code with simpler UP code. * fixup headers to use alternative.h instead of defining their own LOCK / LOCK_PREFIX macros. The patch reuses the i386 version of the alternatives code to avoid code duplication. The code in alternatives.c was shuffled around a bit to reduce the number of #ifdefs needed. It also got some tweaks needed for x86_64 (vsyscall page handling) and new features (noreplacement option which was x86_64 only up to now). Debug printk's are changed from compile-time to runtime. Loosely based on a early version from Bastian Blank Signed-off-by: Gerd Hoffmann Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/i386/kernel/alternative.c | 118 +++++++++++++++++++++++++++++------------ 1 file changed, 85 insertions(+), 33 deletions(-) (limited to 'arch/i386') diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c index 5cbd6f99fb2..50eb0e03777 100644 --- a/arch/i386/kernel/alternative.c +++ b/arch/i386/kernel/alternative.c @@ -4,27 +4,41 @@ #include #include -#define DEBUG 0 -#if DEBUG -# define DPRINTK(fmt, args...) printk(fmt, args) -#else -# define DPRINTK(fmt, args...) -#endif +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); -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[]; +extern unsigned char intelnops[]; static unsigned char *intel_nops[ASM_NOP_MAX+1] = { NULL, intelnops, @@ -36,6 +50,13 @@ static unsigned char *intel_nops[ASM_NOP_MAX+1] = { 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, @@ -47,6 +68,13 @@ static unsigned char *k8_nops[ASM_NOP_MAX+1] = { 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, @@ -58,6 +86,18 @@ static unsigned char *k7_nops[ASM_NOP_MAX+1] = { 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; @@ -67,14 +107,6 @@ static struct nop { { -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; @@ -89,6 +121,14 @@ static unsigned char** find_nop_table(void) 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 @@ -99,6 +139,7 @@ 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); @@ -106,7 +147,16 @@ void apply_alternatives(struct alt_instr *start, struct alt_instr *end) BUG_ON(a->replacementlen > a->instrlen); if (!boot_cpu_has(a->cpuid)) continue; - memcpy(a->instr, a->replacement, a->replacementlen); + 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) { @@ -186,14 +236,6 @@ struct smp_alt_module { 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) @@ -201,6 +243,9 @@ void alternatives_smp_module_add(struct module *mod, char *name, 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, @@ -235,7 +280,7 @@ void alternatives_smp_module_del(struct module *mod) struct smp_alt_module *item; unsigned long flags; - if (smp_alt_once) + if (no_replacement || smp_alt_once) return; spin_lock_irqsave(&smp_alt, flags); @@ -256,7 +301,7 @@ void alternatives_smp_switch(int smp) struct smp_alt_module *mod; unsigned long flags; - if (smp_alt_once) + if (no_replacement || smp_alt_once) return; BUG_ON(!smp && (num_online_cpus() > 1)); @@ -285,6 +330,13 @@ void alternatives_smp_switch(int smp) void __init alternative_instructions(void) { + 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; + } apply_alternatives(__alt_instructions, __alt_instructions_end); /* switch to patch-once-at-boottime-only mode and free the -- cgit v1.2.3