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From:   Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To:     x86@kernel.org
Cc:     Andreas Herrmann <aherrmann@suse.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Chen Yu <yu.c.chen@intel.com>, Len Brown <len.brown@intel.com>,
        Radu Rendec <rrendec@redhat.com>,
        Pierre Gondois <Pierre.Gondois@arm.com>,
        Pu Wen <puwen@hygon.cn>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Sudeep Holla <sudeep.holla@arm.com>,
        Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>,
        Will Deacon <will@kernel.org>, Zhang Rui <rui.zhang@intel.com>,
        Huang Ying <ying.huang@intel.com>,
        "Ravi V. Shankar" <ravi.v.shankar@intel.com>,
        stable@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Subject: [PATCH v4 0/4] x86/cacheinfo: Set the number of leaves per CPU
Date:   Tue, 12 Dec 2023 14:25:15 -0800
Message-Id: <20231212222519.12834-1-ricardo.neri-calderon@linux.intel.com>
Precedence: bulk

Hi,

The interface /sys/devices/system/cpu/cpuX/cache is broken (not populated)
if CPUs have different numbers of subleaves in CPUID 4. This is the case
of Intel Meteor Lake.

This is v4 of a patchset to fix the cache sysfs interface by setting the
number of cache leaves independently for each CPU.

v1, v2, and v3 can be found here[1], here[2], and here[3].

All the tests described in [4] passed.

Changes since v3:
  * Fixed another NULL-pointer dereference when checking the validity of
    the last-level cache info.
  * Added the Reviewed-by tags from Radu and Sudeep. Thanks!
  * Rebased on v6.7-rc5.

Changes since v2:
  * This version uncovered a NULL-pointer dereference in recent changes to
    cacheinfo[5]. This dereference is observed when the system does not
    configure cacheinfo early during boot nor makes corrections later
    during CPU hotplug; as is the case in x86. Patch 1 fixes this issue.

Changes since v1:
  * Dave Hansen suggested to use the existing per-CPU ci_cpu_cacheinfo
    variable. Now the global variable num_cache_leaves became useless.
  * While here, I noticed that init_cache_level() also became useless:
    x86 does not need ci_cpu_cacheinfo::num_levels.

Thanks and BR,
Ricardo

[1]. https://lore.kernel.org/lkml/20230314231658.30169-1-ricardo.neri-calderon@linux.intel.com/
[2]. https://lore.kernel.org/all/20230424001956.21434-1-ricardo.neri-calderon@linux.intel.com/
[3]. https://lore.kernel.org/lkml/20230805012421.7002-1-ricardo.neri-calderon@linux.intel.com/
[4]. https://lore.kernel.org/lkml/20230912032350.GA17008@ranerica-svr.sc.intel.com/
[5]. https://lore.kernel.org/all/20230412185759.755408-1-rrendec@redhat.com/

Ricardo Neri (4):
  cacheinfo: Check for null last-level cache info
  cacheinfo: Allocate memory for memory if not done from the primary CPU
  x86/cacheinfo: Delete global num_cache_leaves
  x86/cacheinfo: Clean out init_cache_level()

 arch/x86/kernel/cpu/cacheinfo.c | 49 +++++++++++++++++----------------
 drivers/base/cacheinfo.c        |  9 +++++-
 2 files changed, 34 insertions(+), 24 deletions(-)

-- 
2.25.1