With CONFIG_OF enabled on x86, we get the following error on boot:
"
        Failed to find cpu0 device node
        Unable to detect cache hierarchy from DT for CPU 0
"
and the cacheinfo fails to get populated in the corresponding sysfs
entries. This is because cache_setup_of_node looks for of_node for
setting up the shared cpu_map without checking that it's already
populated in the architecture specific callback.

In order to indicate that the shared cpu_map is already populated, this
patch introduces a boolean `cpu_map_populated` in struct cpu_cacheinfo
that can be used by the generic code to skip cache_shared_cpu_map_setup.

This patch also sets that boolean for x86.

Cc: Greg Kroah-Hartman <[email protected]>
Signed-off-by: Sudeep Holla <[email protected]>
---
 arch/x86/kernel/cpu/intel_cacheinfo.c | 2 ++
 drivers/base/cacheinfo.c              | 3 +++
 include/linux/cacheinfo.h             | 1 +
 3 files changed, 6 insertions(+)

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c 
b/arch/x86/kernel/cpu/intel_cacheinfo.c
index de6626c18e42..be6337156502 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -934,6 +934,8 @@ static int __populate_cache_leaves(unsigned int cpu)
                ci_leaf_init(this_leaf++, &id4_regs);
                __cache_cpumap_setup(cpu, idx, &id4_regs);
        }
+       this_cpu_ci->cpu_map_populated = true;
+
        return 0;
 }
 
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index e9fd32e91668..ecde8957835a 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -106,6 +106,9 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
        unsigned int index;
        int ret;
 
+       if (this_cpu_ci->cpu_map_populated)
+               return 0;
+
        ret = cache_setup_of_node(cpu);
        if (ret)
                return ret;
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 2189935075b4..a951fd10aaaa 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -71,6 +71,7 @@ struct cpu_cacheinfo {
        struct cacheinfo *info_list;
        unsigned int num_levels;
        unsigned int num_leaves;
+       bool cpu_map_populated;
 };
 
 /*
-- 
2.7.4

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