Commit-ID: ddc5681ed33a279fdc188e98e71f0c539f08c6e6 Gitweb: http://git.kernel.org/tip/ddc5681ed33a279fdc188e98e71f0c539f08c6e6 Author: Shai Fultheim <shai@xxxxxxxxxxx> AuthorDate: Fri, 20 Apr 2012 01:09:11 +0300 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitDate: Mon, 7 May 2012 15:27:37 +0200 x86/cache_info: Fix setup of l2/l3 ids On some architectures (such as vSMP), it is possible to have CPUs with a different number of cores sharing the same cache. The current implementation implicitly assumes that all CPUs will have the same number of cores sharing caches, and as a result, different CPUs can end up with the same l2/l3 ids. Fix this by masking out the shared cache bits, instead of shifting the APICID. By doing so, it is guaranteed that the generated cache ids are always unique. Signed-off-by: Shai Fultheim <shai@xxxxxxxxxxx> [ rebased, simplified, and reworded the commit message] Signed-off-by: Ido Yariv <ido@xxxxxxxxxx> Cc: Borislav Petkov <borislav.petkov@xxxxxxx> Cc: Andreas Herrmann <andreas.herrmann3@xxxxxxx> Cc: Mike Travis <travis@xxxxxxx> Cc: Dave Jones <davej@xxxxxxxxxx> Link: http://lkml.kernel.org/r/1334873351-31142-1-git-send-email-ido@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- arch/x86/kernel/cpu/intel_cacheinfo.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c index b8f3653..9a7c90d 100644 --- a/arch/x86/kernel/cpu/intel_cacheinfo.c +++ b/arch/x86/kernel/cpu/intel_cacheinfo.c @@ -615,14 +615,14 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c) new_l2 = this_leaf.size/1024; num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing; index_msb = get_count_order(num_threads_sharing); - l2_id = c->apicid >> index_msb; + l2_id = c->apicid & ~((1 << index_msb) - 1); break; case 3: new_l3 = this_leaf.size/1024; num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing; index_msb = get_count_order( num_threads_sharing); - l3_id = c->apicid >> index_msb; + l3_id = c->apicid & ~((1 << index_msb) - 1); break; default: break; -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
|