[PATCH v1 19/40] x86/cacheinfo: Standardize _cpuid4_info_regs instance naming

Ahmed S. Darwish
2025-03-04T08:53:12Z

The cacheinfo code frequently uses the output registers from cpuid leaf
0x4. Such registers are cached at struct _cpuid4_info_regs, augmented
with related information, and are then passed across functions.

The naming of these _cpuid4_info_regs instances is confusing at best.

Some instances are called "this_leaf", which is vague as "this" lacks
context and "leaf" is overly generic given that other cpuid leaves are
also processed within cacheinfo. Other _cpuid4_info_regs instances are
just called "base", adding further ambiguity.

Standardize on id4 for all instances.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
arch/x86/kernel/cpu/cacheinfo.c | 97 +++++++++++++++++----------------
1 file changed, 49 insertions(+), 48 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index f825d68e8de6..74a2949ff872 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -573,7 +573,7 @@ cache_get_priv_group(struct cacheinfo *ci)
return &cache_private_group;
}

-static void amd_init_l3_cache(struct _cpuid4_info_regs *this_leaf, int index)
+static void amd_init_l3_cache(struct _cpuid4_info_regs *id4, int index)
{
int node;

@@ -582,16 +582,16 @@ static void amd_init_l3_cache(struct _cpuid4_info_regs *this_leaf, int index)
return;

node = topology_amd_node_id(smp_processor_id());
- this_leaf->nb = node_to_amd_nb(node);
- if (this_leaf->nb && !this_leaf->nb->l3_cache.indices)
- amd_calc_l3_indices(this_leaf->nb);
+ id4->nb = node_to_amd_nb(node);
+ if (id4->nb && !id4->nb->l3_cache.indices)
+ amd_calc_l3_indices(id4->nb);
}
#else
#define amd_init_l3_cache(x, y)
#endif /* CONFIG_AMD_NB && CONFIG_SYSFS */

static int
-cpuid4_cache_lookup_regs(int index, struct _cpuid4_info_regs *this_leaf)
+cpuid4_cache_lookup_regs(int index, struct _cpuid4_info_regs *id4)
{
union _cpuid4_leaf_eax eax;
union _cpuid4_leaf_ebx ebx;
@@ -604,11 +604,11 @@ cpuid4_cache_lookup_regs(int index, struct _cpuid4_info_regs *this_leaf)
&ebx.full, &ecx.full, &edx);
else
amd_cpuid4(index, &eax, &ebx, &ecx);
- amd_init_l3_cache(this_leaf, index);
+ amd_init_l3_cache(id4, index);
} else if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
cpuid_count(0x8000001d, index, &eax.full,
&ebx.full, &ecx.full, &edx);
- amd_init_l3_cache(this_leaf, index);
+ amd_init_l3_cache(id4, index);
} else {
cpuid_count(4, index, &eax.full, &ebx.full, &ecx.full, &edx);
}
@@ -616,13 +616,14 @@ cpuid4_cache_lookup_regs(int index, struct _cpuid4_info_regs *this_leaf)
if (eax.split.type == CTYPE_NULL)
return -EIO; /* better error ? */

- this_leaf->eax = eax;
- this_leaf->ebx = ebx;
- this_leaf->ecx = ecx;
- this_leaf->size = (ecx.split.number_of_sets + 1) *
- (ebx.split.coherency_line_size + 1) *
- (ebx.split.physical_line_partition + 1) *
- (ebx.split.ways_of_associativity + 1);
+ id4->eax = eax;
+ id4->ebx = ebx;
+ id4->ecx = ecx;
+ id4->size = (ecx.split.number_of_sets + 1) *
+ (ebx.split.coherency_line_size + 1) *
+ (ebx.split.physical_line_partition + 1) *
+ (ebx.split.ways_of_associativity + 1);
+
return 0;
}

@@ -754,29 +755,29 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
* parameters cpuid leaf to find the cache details
*/
for (i = 0; i < ci->num_leaves; i++) {
- struct _cpuid4_info_regs this_leaf = {};
+ struct _cpuid4_info_regs id4 = {};
int retval;

- retval = cpuid4_cache_lookup_regs(i, &this_leaf);
+ retval = cpuid4_cache_lookup_regs(i, &id4);
if (retval < 0)
continue;

- switch (this_leaf.eax.split.level) {
+ switch (id4.eax.split.level) {
case 1:
- if (this_leaf.eax.split.type == CTYPE_DATA)
- new_l1d = this_leaf.size/1024;
- else if (this_leaf.eax.split.type == CTYPE_INST)
- new_l1i = this_leaf.size/1024;
+ if (id4.eax.split.type == CTYPE_DATA)
+ new_l1d = id4.size/1024;
+ else if (id4.eax.split.type == CTYPE_INST)
+ new_l1i = id4.size/1024;
break;
case 2:
- new_l2 = this_leaf.size/1024;
- num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
+ new_l2 = id4.size/1024;
+ num_threads_sharing = 1 + id4.eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
l2_id = c->topo.apicid & ~((1 << index_msb) - 1);
break;
case 3:
- new_l3 = this_leaf.size/1024;
- num_threads_sharing = 1 + this_leaf.eax.split.num_threads_sharing;
+ new_l3 = id4.size/1024;
+ num_threads_sharing = 1 + id4.eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
l3_id = c->topo.apicid & ~((1 << index_msb) - 1);
break;
@@ -841,7 +842,7 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
}

static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
- const struct _cpuid4_info_regs *base)
+ const struct _cpuid4_info_regs *id4)
{
struct cpu_cacheinfo *this_cpu_ci;
struct cacheinfo *ci;
@@ -867,7 +868,7 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
} else if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
unsigned int apicid, nshared, first, last;

- nshared = base->eax.split.num_threads_sharing + 1;
+ nshared = id4->eax.split.num_threads_sharing + 1;
apicid = cpu_data(cpu).topo.apicid;
first = apicid - (apicid % nshared);
last = first + nshared - 1;
@@ -898,7 +899,7 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
}

static void __cache_cpumap_setup(unsigned int cpu, int index,
- const struct _cpuid4_info_regs *base)
+ const struct _cpuid4_info_regs *id4)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct cacheinfo *ci, *sibling_ci;
@@ -908,12 +909,12 @@ static void __cache_cpumap_setup(unsigned int cpu, int index,

if (c->x86_vendor == X86_VENDOR_AMD ||
c->x86_vendor == X86_VENDOR_HYGON) {
- if (__cache_amd_cpumap_setup(cpu, index, base))
+ if (__cache_amd_cpumap_setup(cpu, index, id4))
return;
}

ci = this_cpu_ci->info_list + index;
- num_threads_sharing = 1 + base->eax.split.num_threads_sharing;
+ num_threads_sharing = 1 + id4->eax.split.num_threads_sharing;

cpumask_set_cpu(cpu, &ci->shared_cpu_map);
if (num_threads_sharing == 1)
@@ -934,18 +935,18 @@ static void __cache_cpumap_setup(unsigned int cpu, int index,
}

static void ci_info_init(struct cacheinfo *ci,
- const struct _cpuid4_info_regs *base)
+ const struct _cpuid4_info_regs *id4)
{
- ci->id = base->id;
+ ci->id = id4->id;
ci->attributes = CACHE_ID;
- ci->level = base->eax.split.level;
- ci->type = cache_type_map[base->eax.split.type];
- ci->coherency_line_size = base->ebx.split.coherency_line_size + 1;
- ci->ways_of_associativity = base->ebx.split.ways_of_associativity + 1;
- ci->size = base->size;
- ci->number_of_sets = base->ecx.split.number_of_sets + 1;
- ci->physical_line_partition = base->ebx.split.physical_line_partition + 1;
- ci->priv = base->nb;
+ ci->level = id4->eax.split.level;
+ ci->type = cache_type_map[id4->eax.split.type];
+ ci->coherency_line_size = id4->ebx.split.coherency_line_size + 1;
+ ci->ways_of_associativity = id4->ebx.split.ways_of_associativity + 1;
+ ci->size = id4->size;
+ ci->number_of_sets = id4->ecx.split.number_of_sets + 1;
+ ci->physical_line_partition = id4->ebx.split.physical_line_partition + 1;
+ ci->priv = id4->nb;
}

int init_cache_level(unsigned int cpu)
@@ -964,15 +965,15 @@ int init_cache_level(unsigned int cpu)
* ECX as cache index. Then right shift apicid by the number's order to get
* cache id for this cache node.
*/
-static void get_cache_id(int cpu, struct _cpuid4_info_regs *id4_regs)
+static void get_cache_id(int cpu, struct _cpuid4_info_regs *id4)
{
struct cpuinfo_x86 *c = &cpu_data(cpu);
unsigned long num_threads_sharing;
int index_msb;

- num_threads_sharing = 1 + id4_regs->eax.split.num_threads_sharing;
+ num_threads_sharing = 1 + id4->eax.split.num_threads_sharing;
index_msb = get_count_order(num_threads_sharing);
- id4_regs->id = c->topo.apicid >> index_msb;
+ id4->id = c->topo.apicid >> index_msb;
}

int populate_cache_leaves(unsigned int cpu)
@@ -980,15 +981,15 @@ int populate_cache_leaves(unsigned int cpu)
unsigned int idx, ret;
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
struct cacheinfo *ci = this_cpu_ci->info_list;
- struct _cpuid4_info_regs id4_regs = {};
+ struct _cpuid4_info_regs id4 = {};

for (idx = 0; idx < this_cpu_ci->num_leaves; idx++) {
- ret = cpuid4_cache_lookup_regs(idx, &id4_regs);
+ ret = cpuid4_cache_lookup_regs(idx, &id4);
if (ret)
return ret;
- get_cache_id(cpu, &id4_regs);
- ci_info_init(ci++, &id4_regs);
- __cache_cpumap_setup(cpu, idx, &id4_regs);
+ get_cache_id(cpu, &id4);
+ ci_info_init(ci++, &id4);
+ __cache_cpumap_setup(cpu, idx, &id4);
}
this_cpu_ci->cpu_map_populated = true;

--
2.48.1