Messages in this thread | | | Date | Wed, 17 Aug 2022 21:40:29 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86/cacheinfo: Don't use cpu_llc_shared_map for !CONFIG_SMP |
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On Wed, Aug 10, 2022 at 09:15:15AM -0700, Saurabh Sengar wrote: > cpu_llc_shared_map is always declared and defined, but populated in > arch/x86/kernel/smpboot.c which only builds for CONFIG_SMP=y. For > UniProcessor builds this mask is never populated and hence invalid. > Current code doesn't handle the case of AMD UniProcessor correctly,
What is "AMD UniProcessor"?
> which results "shared_cpu_map" and "shared_cpu_list" files missing from > sysfs entries for l3 cache. This patch fixes this issue.
What issue exactly?
What is the real life use case for this?
> This code used to work because of a another bug in 'cpumask_next', > where in the CONFIG_SMP=n case the cpumask_next() ignores empty mask > that results as if CPU 0 was set. This bug in 'cpumask_next' was fixed by > following commit, which exposes the cpu_llc_shared_map bug. > > b81dce77ced ("cpumask: Fix invalid uniprocessor mask assumption") > > Fixes: 2b83809a5e ("x86/cpu/amd: Derive L3 shared_cpu_map from cpu_llc_shared_mask")
Add
--- [core] abbrev = 12
[alias] one = show -s --pretty='format:%h (\"%s\")' ---
to your git .config so that when you do
$ git one <commit id>
you can get the proper formatting and abbreviated sha1 for commits.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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