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authorAndi Kleen <andi@firstfloor.org>2008-10-15 22:01:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-10-16 11:21:31 -0700
commit25ddbb18aae33ad255eb9f35aacebe3af01e1e9c (patch)
tree8df1f840a226ed640c2096710b7d0f1f4d1b88aa /arch
parent889d51a10712b6fd6175196626de2116858394f4 (diff)
Make the taint flags reliable
It's somewhat unlikely that it happens, but right now a race window between interrupts or machine checks or oopses could corrupt the tainted bitmap because it is modified in a non atomic fashion. Convert the taint variable to an unsigned long and use only atomic bit operations on it. Unfortunately this means the intvec sysctl functions cannot be used on it anymore. It turned out the taint sysctl handler could actually be simplified a bit (since it only increases capabilities) so this patch actually removes code. [akpm@linux-foundation.org: remove unneeded include] Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/smpboot.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 8c3aca7cb34..7ed9e070a6e 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -282,6 +282,8 @@ static void __cpuinit smp_callin(void)
cpu_set(cpuid, cpu_callin_map);
}
+static int __cpuinitdata unsafe_smp;
+
/*
* Activate a secondary processor.
*/
@@ -397,7 +399,7 @@ static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
goto valid_k7;
/* If we get here, not a certified SMP capable AMD system. */
- add_taint(TAINT_UNSAFE_SMP);
+ unsafe_smp = 1;
}
valid_k7:
@@ -414,12 +416,10 @@ static void __cpuinit smp_checks(void)
* Don't taint if we are running SMP kernel on a single non-MP
* approved Athlon
*/
- if (tainted & TAINT_UNSAFE_SMP) {
- if (num_online_cpus())
- printk(KERN_INFO "WARNING: This combination of AMD"
- "processors is not suitable for SMP.\n");
- else
- tainted &= ~TAINT_UNSAFE_SMP;
+ if (unsafe_smp && num_online_cpus() > 1) {
+ printk(KERN_INFO "WARNING: This combination of AMD"
+ "processors is not suitable for SMP.\n");
+ add_taint(TAINT_UNSAFE_SMP);
}
}