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author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-04 23:57:09 +0400 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-04 23:57:09 +0400 |
commit | 8e8da023f5af71662867729db5547dc54786093c (patch) | |
tree | 0108c8b0bac10268a3156aaf042466b8815d1330 /drivers/pci | |
parent | e5fd47bfab2df0c2184cc0bf4245d8e1bb7724fb (diff) | |
download | linux-8e8da023f5af71662867729db5547dc54786093c.tar.xz |
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>
Diffstat (limited to 'drivers/pci')
0 files changed, 0 insertions, 0 deletions