From b7fb4af06c18496950a45b365f7a09c47ea64c17 Mon Sep 17 00:00:00 2001 From: Jeremy Fitzhardinge Date: Wed, 2 May 2007 19:27:13 +0200 Subject: [PATCH] i386: Allow boot-time disable of SMP altinstructions Add "noreplace-smp" to disable SMP instruction replacement. Signed-off-by: Jeremy Fitzhardinge Signed-off-by: Andi Kleen --- arch/i386/kernel/alternative.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) (limited to 'arch/i386/kernel/alternative.c') diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c index f09635408049..9b8e85a8edec 100644 --- a/arch/i386/kernel/alternative.c +++ b/arch/i386/kernel/alternative.c @@ -5,6 +5,7 @@ #include #include +static int noreplace_smp = 0; static int smp_alt_once = 0; static int debug_alternative = 0; @@ -13,15 +14,23 @@ static int __init bootonly(char *str) smp_alt_once = 1; return 1; } +__setup("smp-alt-boot", bootonly); + static int __init debug_alt(char *str) { debug_alternative = 1; return 1; } - -__setup("smp-alt-boot", bootonly); __setup("debug-alternative", debug_alt); +static int __init setup_noreplace_smp(char *str) +{ + noreplace_smp = 1; + return 1; +} +__setup("noreplace-smp", setup_noreplace_smp); + + #define DPRINTK(fmt, args...) if (debug_alternative) \ printk(KERN_DEBUG fmt, args) @@ -185,6 +194,9 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end { u8 **ptr; + if (noreplace_smp) + return; + for (ptr = start; ptr < end; ptr++) { if (*ptr < text) continue; @@ -219,6 +231,9 @@ void alternatives_smp_module_add(struct module *mod, char *name, 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, @@ -253,7 +268,7 @@ void alternatives_smp_module_del(struct module *mod) struct smp_alt_module *item; unsigned long flags; - if (smp_alt_once) + if (smp_alt_once || noreplace_smp) return; spin_lock_irqsave(&smp_alt, flags); @@ -284,7 +299,7 @@ void alternatives_smp_switch(int smp) return; #endif - if (smp_alt_once) + if (noreplace_smp || smp_alt_once) return; BUG_ON(!smp && (num_online_cpus() > 1)); -- cgit v1.2.3