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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-04 20:57:09 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-04 20:57:09 +0100 |
| commit | 8e8da023f5af71662867729db5547dc54786093c (patch) | |
| tree | 0108c8b0bac10268a3156aaf042466b8815d1330 | |
| parent | xen/pm_idle: Make pm_idle be default_idle under Xen. (diff) | |
| download | linux-8e8da023f5af71662867729db5547dc54786093c.tar.xz linux-8e8da023f5af71662867729db5547dc54786093c.zip | |
x86: Fix boot failures on older AMD CPU's
People with old AMD chips are getting hung boots, because commit
bcb80e53877c ("x86, microcode, AMD: Add microcode revision to
/proc/cpuinfo") moved the microcode detection too early into
"early_init_amd()".
At that point we are *so* early in the booth that the exception tables
haven't even been set up yet, so the whole
rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy);
doesn't actually work: if the rdmsr does a GP fault (due to non-existant
MSR register on older CPU's), we can't fix it up yet, and the boot fails.
Fix it by simply moving the code to a slightly later point in the boot
(init_amd() instead of early_init_amd()), since the kernel itself
doesn't even really care about the microcode patchlevel at this point
(or really ever: it's made available to user space in /proc/cpuinfo, and
updated if you do a microcode load).
Reported-tested-and-bisected-by: Larry Finger <Larry.Finger@lwfinger.net>
Tested-by: Bob Tracy <rct@gherkin.frus.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | arch/x86/kernel/cpu/amd.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index c7e46cb35327..0bab2b18bb20 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -442,8 +442,6 @@ static void __cpuinit bsp_init_amd(struct cpuinfo_x86 *c) static void __cpuinit early_init_amd(struct cpuinfo_x86 *c) { - u32 dummy; - early_init_amd_mc(c); /* @@ -473,12 +471,12 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c) set_cpu_cap(c, X86_FEATURE_EXTD_APICID); } #endif - - rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy); } static void __cpuinit init_amd(struct cpuinfo_x86 *c) { + u32 dummy; + #ifdef CONFIG_SMP unsigned long long value; @@ -657,6 +655,8 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) checking_wrmsrl(MSR_AMD64_MCx_MASK(4), mask); } } + + rdmsr_safe(MSR_AMD64_PATCH_LEVEL, &c->microcode, &dummy); } #ifdef CONFIG_X86_32 |