[PATCH v1 32/40] x86/cacheinfo: Use consolidated leaf 0x2 descriptor table

Ahmed S. Darwish
2025-03-04T08:53:52Z

cpuid leaf 0x2 output is a stream of one-byte descriptors, each implying
certain details about the CPU's cache and TLB entries.

At previous commits, the mapping tables for such descriptors were merged
into one consolidated table. The mapping was also transformed into a
hash lookup instead of a loop-based lookup for each descriptor.

Use the new consolidated table and its hash-based lookup through the
for_each_leaf_0x2_tlb_entry() accessor. Remove the old cache-specific
mapping, cache_table[], as it is no longer used.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
arch/x86/include/asm/cpuid/types.h | 2 +-
arch/x86/kernel/cpu/cacheinfo.c | 114 ++---------------------------
2 files changed, 9 insertions(+), 107 deletions(-)

diff --git a/arch/x86/include/asm/cpuid/types.h b/arch/x86/include/asm/cpuid/types.h
index c23f187060aa..4af9f6c32895 100644
--- a/arch/x86/include/asm/cpuid/types.h
+++ b/arch/x86/include/asm/cpuid/types.h
@@ -80,7 +80,7 @@ static inline void get_leaf_0x2_regs(union leaf_0x2_regs *regs)

/*
* Leaf 0x2 1-byte descriptors' cache types
- * To be used for their mappings at cache_table[]
+ * To be used for their mappings at cpuid_0x2_table[].
*
* Start at 1 since type 0 is reserved for HW byte descriptors which are
* not recognized by the kernel; i.e., those without an explicit mapping
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index a7fccbab268d..a1cfb6716272 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -34,90 +34,6 @@ static cpumask_var_t cpu_cacheinfo_mask;
/* Kernel controls MTRR and/or PAT MSRs. */
unsigned int memory_caching_control __ro_after_init;

-struct _cache_table {
- unsigned char descriptor;
- enum _cache_table_type type;
- short size;
-};
-
-#define MB(x) ((x) * 1024)
-
-/* All the cache descriptor types we care about (no TLB or
- trace cache entries) */
-
-static const struct _cache_table cache_table[] =
-{
- { 0x06, CACHE_L1_INST, 8 }, /* 4-way set assoc, 32 byte line size */
- { 0x08, CACHE_L1_INST, 16 }, /* 4-way set assoc, 32 byte line size */
- { 0x09, CACHE_L1_INST, 32 }, /* 4-way set assoc, 64 byte line size */
- { 0x0a, CACHE_L1_DATA, 8 }, /* 2 way set assoc, 32 byte line size */
- { 0x0c, CACHE_L1_DATA, 16 }, /* 4-way set assoc, 32 byte line size */
- { 0x0d, CACHE_L1_DATA, 16 }, /* 4-way set assoc, 64 byte line size */
- { 0x0e, CACHE_L1_DATA, 24 }, /* 6-way set assoc, 64 byte line size */
- { 0x21, CACHE_L2, 256 }, /* 8-way set assoc, 64 byte line size */
- { 0x22, CACHE_L3, 512 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x23, CACHE_L3, MB(1) }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x25, CACHE_L3, MB(2) }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x29, CACHE_L3, MB(4) }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x2c, CACHE_L1_DATA, 32 }, /* 8-way set assoc, 64 byte line size */
- { 0x30, CACHE_L1_INST, 32 }, /* 8-way set assoc, 64 byte line size */
- { 0x39, CACHE_L2, 128 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x3a, CACHE_L2, 192 }, /* 6-way set assoc, sectored cache, 64 byte line size */
- { 0x3b, CACHE_L2, 128 }, /* 2-way set assoc, sectored cache, 64 byte line size */
- { 0x3c, CACHE_L2, 256 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x3d, CACHE_L2, 384 }, /* 6-way set assoc, sectored cache, 64 byte line size */
- { 0x3e, CACHE_L2, 512 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x3f, CACHE_L2, 256 }, /* 2-way set assoc, 64 byte line size */
- { 0x41, CACHE_L2, 128 }, /* 4-way set assoc, 32 byte line size */
- { 0x42, CACHE_L2, 256 }, /* 4-way set assoc, 32 byte line size */
- { 0x43, CACHE_L2, 512 }, /* 4-way set assoc, 32 byte line size */
- { 0x44, CACHE_L2, MB(1) }, /* 4-way set assoc, 32 byte line size */
- { 0x45, CACHE_L2, MB(2) }, /* 4-way set assoc, 32 byte line size */
- { 0x46, CACHE_L3, MB(4) }, /* 4-way set assoc, 64 byte line size */
- { 0x47, CACHE_L3, MB(8) }, /* 8-way set assoc, 64 byte line size */
- { 0x48, CACHE_L2, MB(3) }, /* 12-way set assoc, 64 byte line size */
- { 0x49, CACHE_L3, MB(4) }, /* 16-way set assoc, 64 byte line size */
- { 0x4a, CACHE_L3, MB(6) }, /* 12-way set assoc, 64 byte line size */
- { 0x4b, CACHE_L3, MB(8) }, /* 16-way set assoc, 64 byte line size */
- { 0x4c, CACHE_L3, MB(12) }, /* 12-way set assoc, 64 byte line size */
- { 0x4d, CACHE_L3, MB(16) }, /* 16-way set assoc, 64 byte line size */
- { 0x4e, CACHE_L2, MB(6) }, /* 24-way set assoc, 64 byte line size */
- { 0x60, CACHE_L1_DATA, 16 }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x66, CACHE_L1_DATA, 8 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x67, CACHE_L1_DATA, 16 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x68, CACHE_L1_DATA, 32 }, /* 4-way set assoc, sectored cache, 64 byte line size */
- { 0x78, CACHE_L2, MB(1) }, /* 4-way set assoc, 64 byte line size */
- { 0x79, CACHE_L2, 128 }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x7a, CACHE_L2, 256 }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x7b, CACHE_L2, 512 }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x7c, CACHE_L2, MB(1) }, /* 8-way set assoc, sectored cache, 64 byte line size */
- { 0x7d, CACHE_L2, MB(2) }, /* 8-way set assoc, 64 byte line size */
- { 0x7f, CACHE_L2, 512 }, /* 2-way set assoc, 64 byte line size */
- { 0x80, CACHE_L2, 512 }, /* 8-way set assoc, 64 byte line size */
- { 0x82, CACHE_L2, 256 }, /* 8-way set assoc, 32 byte line size */
- { 0x83, CACHE_L2, 512 }, /* 8-way set assoc, 32 byte line size */
- { 0x84, CACHE_L2, MB(1) }, /* 8-way set assoc, 32 byte line size */
- { 0x85, CACHE_L2, MB(2) }, /* 8-way set assoc, 32 byte line size */
- { 0x86, CACHE_L2, 512 }, /* 4-way set assoc, 64 byte line size */
- { 0x87, CACHE_L2, MB(1) }, /* 8-way set assoc, 64 byte line size */
- { 0xd0, CACHE_L3, 512 }, /* 4-way set assoc, 64 byte line size */
- { 0xd1, CACHE_L3, MB(1) }, /* 4-way set assoc, 64 byte line size */
- { 0xd2, CACHE_L3, MB(2) }, /* 4-way set assoc, 64 byte line size */
- { 0xd6, CACHE_L3, MB(1) }, /* 8-way set assoc, 64 byte line size */
- { 0xd7, CACHE_L3, MB(2) }, /* 8-way set assoc, 64 byte line size */
- { 0xd8, CACHE_L3, MB(4) }, /* 12-way set assoc, 64 byte line size */
- { 0xdc, CACHE_L3, MB(2) }, /* 12-way set assoc, 64 byte line size */
- { 0xdd, CACHE_L3, MB(4) }, /* 12-way set assoc, 64 byte line size */
- { 0xde, CACHE_L3, MB(8) }, /* 12-way set assoc, 64 byte line size */
- { 0xe2, CACHE_L3, MB(2) }, /* 16-way set assoc, 64 byte line size */
- { 0xe3, CACHE_L3, MB(4) }, /* 16-way set assoc, 64 byte line size */
- { 0xe4, CACHE_L3, MB(8) }, /* 16-way set assoc, 64 byte line size */
- { 0xea, CACHE_L3, MB(12) }, /* 24-way set assoc, 64 byte line size */
- { 0xeb, CACHE_L3, MB(18) }, /* 24-way set assoc, 64 byte line size */
- { 0xec, CACHE_L3, MB(24) }, /* 24-way set assoc, 64 byte line size */
-};
-
-
enum _cache_type {
CTYPE_NULL = 0,
CTYPE_DATA = 1,
@@ -436,16 +352,6 @@ void init_hygon_cacheinfo(struct cpuinfo_x86 *c)
ci->num_leaves = find_num_cache_leaves(c);
}

-static const struct _cache_table *cache_table_get(u8 desc)
-{
- for (int i = 0; i < ARRAY_SIZE(cache_table); i++) {
- if (cache_table[i].descriptor == desc)
- return &cache_table[i];
- }
-
- return NULL;
-}
-
void init_intel_cacheinfo(struct cpuinfo_x86 *c)
{
/* Cache sizes */
@@ -502,21 +408,17 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)

/* Don't use CPUID(2) if CPUID(4) is supported. */
if (!ci->num_leaves && c->cpuid_level > 1) {
- const struct _cache_table *entry;
+ const struct leaf_0x2_table *entry;
union leaf_0x2_regs regs;
- u8 *desc;
+ u8 *ptr;

get_leaf_0x2_regs(&regs);
- for_each_leaf_0x2_desc(regs, desc) {
- entry = cache_table_get(*desc);
- if (!entry)
- continue;
-
- switch (entry->type) {
- case CACHE_L1_INST: l1i += entry->size; break;
- case CACHE_L1_DATA: l1d += entry->size; break;
- case CACHE_L2: l2 += entry->size; break;
- case CACHE_L3: l3 += entry->size; break;
+ for_each_leaf_0x2_entry(regs, ptr, entry) {
+ switch (entry->c_type) {
+ case CACHE_L1_INST: l1i += entry->c_size; break;
+ case CACHE_L1_DATA: l1d += entry->c_size; break;
+ case CACHE_L2: l2 += entry->c_size; break;
+ case CACHE_L3: l3 += entry->c_size; break;
}
}
}
--
2.48.1