Complete the AMD CPUID(4) emulation logic, which uses CPUID(0x80000006)
for L2/L3 cache info and an assocs[] associativity mapping array, by
adding entries for 3-way caches and 6-way caches.
Properly handle the case where CPUID(0x80000006) returns an L2/L3
associativity of 9. This is not real associativity, but a marker to
indicate that the respective L2/L3 cache information should be retrieved
from CPUID(0x8000001d) instead. If such a marker is encountered, return
early from legacy_amd_cpuid4(), thus effectively emulating an "invalid
index" CPUID(4) response with a cache type of zero.
When checking if CPUID(0x80000006) L2/L3 cache info output is valid, and
given the associtivity marker 9 above, do not just check if the whole
ECX/EDX register is zero. Rather, check if the associativity is zero or
9. An associativity of zero implies no L2/L3 cache, which make it the
more correct check anyway vs. a zero check of the whole output register.
Fixes: a326e948c538 ("x86, cacheinfo: Fixup L3 cache information for AMD multi-node processors")
Cc: stable@vger.kernel.org
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
arch/x86/kernel/cpu/cacheinfo.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 7a95e1ce73f8..038f819da20e 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -208,13 +208,20 @@ union l3_cache {
unsigned val;
};
+/*
+ * AMD_L2_L3_INVALID_ASSOC: Cache info for the respective L2/L3 cache should
+ * be determined from CPUID(0x8000001d) instead of CPUID(0x80000006).
+ */
#define AMD_CPUID4_FULLY_ASSOCIATIVE 0xffff
+#define AMD_L2_L3_INVALID_ASSOC 0x9
/* L2/L3 associativity mapping */
static const unsigned short assocs[] = {
[1] = 1,
[2] = 2,
+ [3] = 3,
[4] = 4,
+ [5] = 6,
[6] = 8,
[8] = 16,
[0xa] = 32,
@@ -267,7 +274,7 @@ amd_cpuid4(int leaf, union _cpuid4_leaf_eax *eax,
size_in_kb = l1->size_in_kb;
break;
case 2:
- if (!l2.val)
+ if (!l2.assoc || l2.assoc == AMD_L2_L3_INVALID_ASSOC)
return;
assoc = assocs[l2.assoc];
line_size = l2.line_size;
@@ -276,7 +283,7 @@ amd_cpuid4(int leaf, union _cpuid4_leaf_eax *eax,
size_in_kb = __this_cpu_read(cpu_info.x86_cache_size);
break;
case 3:
- if (!l3.val)
+ if (!l3.assoc || l3.assoc == AMD_L2_L3_INVALID_ASSOC)
return;
assoc = assocs[l3.assoc];
line_size = l3.line_size;
--
2.49.0