[PATCH] x86/CPU/AMD: Fix LLC ID bit-shift calculation

Suravee Suthikulpanit
2018-06-13T18:43:49Z

The current logic incorrectly calculates the LLC ID from the APIC ID.
Unless specified otherwise, the LLC ID should be calculated from
the count order of the number of threads sharing cache.

Fixes: 68091ee7ac3c ("Calculate last level cache ID from number of sharing threads")
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
arch/x86/kernel/cpu/cacheinfo.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 38354c6..0c5fcbd 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -671,7 +671,7 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, int cpu, u8 node_id)
num_sharing_cache = ((eax >> 14) & 0xfff) + 1;

if (num_sharing_cache) {
- int bits = get_count_order(num_sharing_cache) - 1;
+ int bits = get_count_order(num_sharing_cache);

per_cpu(cpu_llc_id, cpu) = c->apicid >> bits;
}
--
2.7.4