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authorAndi Kleen <ak@suse.de>2007-04-24 07:05:37 -0400
committerAndi Kleen <andi@basil.nowhere.org>2007-04-24 07:05:37 -0400
commit9ce883becb83190061369940de9c415595836c9b (patch)
tree61f2a1717e7d46751559a3dc897c05de8dfdb6d5 /arch
parentcf6387daf8858bdcb3e123034ca422e8979d73f1 (diff)
[PATCH] x86: Remove noreplacement option
noreplacement is dangerous on modern systems because it will not replace the context switch FNSAVE with SSE aware FXSAVE. But other places in the kernel still assume SSE and do FXSAVE and the CPU will then access FXSAVE information with FNSAVE and cause corruption. Easiest way to avoid this is to remove the option. It was mostly for paranoia reasons anyways and alternative()s have been stable for some time. Thanks to Jeremy F. for reporting and helping debug it. Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/i386/kernel/alternative.c21
1 files changed, 2 insertions, 19 deletions
diff --git a/arch/i386/kernel/alternative.c b/arch/i386/kernel/alternative.c
index 9eca21b49f6b..426f59b0106b 100644
--- a/arch/i386/kernel/alternative.c
+++ b/arch/i386/kernel/alternative.c
@@ -5,15 +5,9 @@
5#include <asm/alternative.h> 5#include <asm/alternative.h>
6#include <asm/sections.h> 6#include <asm/sections.h>
7 7
8static int no_replacement = 0;
9static int smp_alt_once = 0; 8static int smp_alt_once = 0;
10static int debug_alternative = 0; 9static int debug_alternative = 0;
11 10
12static int __init noreplacement_setup(char *s)
13{
14 no_replacement = 1;
15 return 1;
16}
17static int __init bootonly(char *str) 11static int __init bootonly(char *str)
18{ 12{
19 smp_alt_once = 1; 13 smp_alt_once = 1;
@@ -25,7 +19,6 @@ static int __init debug_alt(char *str)
25 return 1; 19 return 1;
26} 20}
27 21
28__setup("noreplacement", noreplacement_setup);
29__setup("smp-alt-boot", bootonly); 22__setup("smp-alt-boot", bootonly);
30__setup("debug-alternative", debug_alt); 23__setup("debug-alternative", debug_alt);
31 24
@@ -252,9 +245,6 @@ void alternatives_smp_module_add(struct module *mod, char *name,
252 struct smp_alt_module *smp; 245 struct smp_alt_module *smp;
253 unsigned long flags; 246 unsigned long flags;
254 247
255 if (no_replacement)
256 return;
257
258 if (smp_alt_once) { 248 if (smp_alt_once) {
259 if (boot_cpu_has(X86_FEATURE_UP)) 249 if (boot_cpu_has(X86_FEATURE_UP))
260 alternatives_smp_unlock(locks, locks_end, 250 alternatives_smp_unlock(locks, locks_end,
@@ -289,7 +279,7 @@ void alternatives_smp_module_del(struct module *mod)
289 struct smp_alt_module *item; 279 struct smp_alt_module *item;
290 unsigned long flags; 280 unsigned long flags;
291 281
292 if (no_replacement || smp_alt_once) 282 if (smp_alt_once)
293 return; 283 return;
294 284
295 spin_lock_irqsave(&smp_alt, flags); 285 spin_lock_irqsave(&smp_alt, flags);
@@ -320,7 +310,7 @@ void alternatives_smp_switch(int smp)
320 return; 310 return;
321#endif 311#endif
322 312
323 if (no_replacement || smp_alt_once) 313 if (smp_alt_once)
324 return; 314 return;
325 BUG_ON(!smp && (num_online_cpus() > 1)); 315 BUG_ON(!smp && (num_online_cpus() > 1));
326 316
@@ -386,13 +376,6 @@ extern struct paravirt_patch __start_parainstructions[],
386void __init alternative_instructions(void) 376void __init alternative_instructions(void)
387{ 377{
388 unsigned long flags; 378 unsigned long flags;
389 if (no_replacement) {
390 printk(KERN_INFO "(SMP-)alternatives turned off\n");
391 free_init_pages("SMP alternatives",
392 (unsigned long)__smp_alt_begin,
393 (unsigned long)__smp_alt_end);
394 return;
395 }
396 379
397 local_irq_save(flags); 380 local_irq_save(flags);
398 apply_alternatives(__alt_instructions, __alt_instructions_end); 381 apply_alternatives(__alt_instructions, __alt_instructions_end);