x86, alternatives: Use 16-bit numbers for cpufeature index
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From: Ingo Molnar on 29 Jun 2010 05:20 * tip-bot for tip-bot for H. Peter Anvin <hpa(a)linux.intel.com> wrote: > Commit-ID: 5dc71d49a7c209b77cd257049a2cdb99ed1008c0 > Gitweb: http://git.kernel.org/tip/5dc71d49a7c209b77cd257049a2cdb99ed1008c0 > Author: tip-bot for H. Peter Anvin <hpa(a)linux.intel.com> > AuthorDate: Thu, 10 Jun 2010 00:10:43 +0000 > Committer: H. Peter Anvin <hpa(a)zytor.com> > CommitDate: Thu, 10 Jun 2010 23:20:34 -0700 > > x86, alternatives: Use 16-bit numbers for cpufeature index > > We already have cpufeature indicies above 255, so use a 16-bit number > for the alternatives index. This consumes a padding field and so > doesn't add any size, but it means that abusing the padding field to > create assembly errors on overflow no longer works. We can retain the > test simply by redirecting it to the .discard section, however. > > Signed-off-by: H. Peter Anvin <hpa(a)linux.intel.com> > LKML-Reference: <tip-f88731e3068f9d1392ba71cc9f50f035d26a0d4f(a)git.kernel.org> > Signed-off-by: H. Peter Anvin <hpa(a)zytor.com> > --- > arch/x86/include/asm/alternative.h | 7 ++++--- > arch/x86/include/asm/cpufeature.h | 10 ++++++---- > 2 files changed, 10 insertions(+), 7 deletions(-) Hm, this patch is causing trouble in -tip testing again - it's triggering a colorful boot crash: [ 2.220002] calling inet_init+0x0/0x23d @ 1 [ 2.223343] NET: Registered protocol family 2 [ 2.226727] IP route cache hash table entries: 32768 (order: 6, 262144 bytes) [ 2.233492] ------------[ cut here ]------------ [ 2.236671] WARNING: at mm/vmalloc.c:107 vmap_page_range_noflush+0x309/0x3a0() [ 2.240001] Modules linked in: .... [ 3.090002] Kernel panic - not syncing: Failed to allocate TCP established hash table So i've zapped them again. We really need to get to the bottom of this. Config and bootlog attached. The crash looks very weird - and it's consistent with possible effects of some sort of code patching failure/mismatch. It goes away if i revert these two: a3d2d12: x86, alternatives: correct obsolete use of "u8" in static_cpu_has() 5dc71d4: x86, alternatives: Use 16-bit numbers for cpufeature index I reproduced the crash twice before testing the revert. Thanks, Ingo |