[tip: x86/urgent] x86/cacheinfo: Add a cpu_llc_shared_mask() UP variant

tip-bot2 for Borislav Petkov
2022-09-29T09:04:20Z

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID: df5b035b5683d6a25f077af889fb88e09827f8bc
Gitweb: https://git.kernel.org/tip/df5b035b5683d6a25f077af889fb88e09827f8bc
Author: Borislav Petkov <bp@suse.de>
AuthorDate: Fri, 19 Aug 2022 19:47:44 +02:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 28 Sep 2022 18:35:37 +02:00

x86/cacheinfo: Add a cpu_llc_shared_mask() UP variant

On a CONFIG_SMP=n kernel, the LLC shared mask is 0, which prevents
__cache_amd_cpumap_setup() from doing the L3 masks setup, and more
specifically from setting up the shared_cpu_map and shared_cpu_list
files in sysfs, leading to lscpu from util-linux getting confused and
segfaulting.

Add a cpu_llc_shared_mask() UP variant which returns a mask with a
single bit set, i.e., for CPU0.

Fixes: 2b83809a5e6d ("x86/cpu/amd: Derive L3 shared_cpu_map from cpu_llc_shared_mask")
Reported-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/1660148115-302-1-git-send-email-ssengar@linux.microsoft.com
---
arch/x86/include/asm/smp.h | 25 +++++++++++++++----------
1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h
index 81a0211..a73bced 100644
--- a/arch/x86/include/asm/smp.h
+++ b/arch/x86/include/asm/smp.h
@@ -21,16 +21,6 @@ DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id);
DECLARE_PER_CPU_READ_MOSTLY(u16, cpu_l2c_id);
DECLARE_PER_CPU_READ_MOSTLY(int, cpu_number);

-static inline struct cpumask *cpu_llc_shared_mask(int cpu)
-{
- return per_cpu(cpu_llc_shared_map, cpu);
-}
-
-static inline struct cpumask *cpu_l2c_shared_mask(int cpu)
-{
- return per_cpu(cpu_l2c_shared_map, cpu);
-}
-
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid);
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid);
DECLARE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_bios_cpu_apicid);
@@ -172,6 +162,16 @@ extern int safe_smp_processor_id(void);
# define safe_smp_processor_id() smp_processor_id()
#endif

+static inline struct cpumask *cpu_llc_shared_mask(int cpu)
+{
+ return per_cpu(cpu_llc_shared_map, cpu);
+}
+
+static inline struct cpumask *cpu_l2c_shared_mask(int cpu)
+{
+ return per_cpu(cpu_l2c_shared_map, cpu);
+}
+
#else /* !CONFIG_SMP */
#define wbinvd_on_cpu(cpu) wbinvd()
static inline int wbinvd_on_all_cpus(void)
@@ -179,6 +179,11 @@ static inline int wbinvd_on_all_cpus(void)
wbinvd();
return 0;
}
+
+static inline struct cpumask *cpu_llc_shared_mask(int cpu)
+{
+ return (struct cpumask *)cpumask_of(0);
+}
#endif /* CONFIG_SMP */

extern unsigned disabled_cpus;