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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-05-02 19:27:13 +0200 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2007-05-02 19:27:13 +0200 |
| commit | b7fb4af06c18496950a45b365f7a09c47ea64c17 (patch) | |
| tree | 2ea129cad7d28482c9b8582476a62cdce139571f | |
| parent | d0175ab64412aabc93da8682aaa99124d6815056 (diff) | |
| download | linux-b7fb4af06c18496950a45b365f7a09c47ea64c17.tar.bz2 | |
[PATCH] i386: Allow boot-time disable of SMP altinstructions
Add "noreplace-smp" to disable SMP instruction replacement.
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andi Kleen <ak@suse.de>
| -rw-r--r-- | Documentation/kernel-parameters.txt | 6 | ||||
| -rw-r--r-- | arch/i386/kernel/alternative.c | 23 |
2 files changed, 25 insertions, 4 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 94ce0d20253d..242b3a09b6ce 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1164,6 +1164,9 @@ and is between 256 and 4096 characters. It is defined in the file nomce [IA-32] Machine Check Exception + noreplace-smp [IA-32,SMP] Don't replace SMP instructions + with UP alternatives + noresidual [PPC] Don't use residual data on PReP machines. noresume [SWSUSP] Disables resume and restores original swap @@ -1569,6 +1572,9 @@ and is between 256 and 4096 characters. It is defined in the file smart2= [HW] Format: <io1>[,<io2>[,...,<io8>]] + smp-alt-once [IA-32,SMP] On a hotplug CPU system, only + attempt to substitute SMP alternatives once at boot. + snd-ad1816a= [HW,ALSA] snd-ad1848= [HW,ALSA] 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 <asm/alternative.h> #include <asm/sections.h> +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)); |