[PATCH v1 40/40] x86/cacheinfo: Apply maintainer-tip coding style fixes

Ahmed S. Darwish
2025-03-04T08:54:16Z

The x86/cacheinfo code has been heavily refactored and fleshed out at
parent commits, where any necessary coding style fixes were also done
in place.

Apply maintainer-tip.rst coding style fixes to the rest of the code,
and align its assignment expressions for readability.

At cacheinfo_amd_init_llc_id(), rename variable msb to index_msb as this
is how it's called at the rest of cacheinfo.c code.

Signed-off-by: Ahmed S. Darwish <darwi@linutronix.de>
---
arch/x86/kernel/cpu/cacheinfo.c | 214 ++++++++++++++++----------------
1 file changed, 108 insertions(+), 106 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index f85a3ddfc3cc..a2359590dde7 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -1,11 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
/*
- * Routines to identify caches on Intel CPU.
+ * x86 CPU caches detection and configuration
*
- * Changes:
- * Venkatesh Pallipadi : Adding cache identification through cpuid(4)
- * Ashok Raj <ashok.raj@intel.com>: Work with CPU hotplug infrastructure.
- * Andi Kleen / Andreas Herrmann : CPUID4 emulation on AMD.
+ * Previous changes
+ * - Venkatesh Pallipadi: Cache identification through CPUID(4)
+ * - Ashok Raj <ashok.raj@intel.com>: Work with CPU hotplug infrastructure
+ * - Andi Kleen / Andreas Herrmann: CPUID(4) emulation on AMD
*/

#include <linux/cacheinfo.h>
@@ -35,37 +35,37 @@ static cpumask_var_t cpu_cacheinfo_mask;
unsigned int memory_caching_control __ro_after_init;

enum _cache_type {
- CTYPE_NULL = 0,
- CTYPE_DATA = 1,
- CTYPE_INST = 2,
- CTYPE_UNIFIED = 3
+ CTYPE_NULL = 0,
+ CTYPE_DATA = 1,
+ CTYPE_INST = 2,
+ CTYPE_UNIFIED = 3
};

union _cpuid4_leaf_eax {
struct {
- enum _cache_type type:5;
- unsigned int level:3;
- unsigned int is_self_initializing:1;
- unsigned int is_fully_associative:1;
- unsigned int reserved:4;
- unsigned int num_threads_sharing:12;
- unsigned int num_cores_on_die:6;
+ enum _cache_type type :5;
+ unsigned int level :3;
+ unsigned int is_self_initializing :1;
+ unsigned int is_fully_associative :1;
+ unsigned int reserved :4;
+ unsigned int num_threads_sharing :12;
+ unsigned int num_cores_on_die :6;
} split;
u32 full;
};

union _cpuid4_leaf_ebx {
struct {
- unsigned int coherency_line_size:12;
- unsigned int physical_line_partition:10;
- unsigned int ways_of_associativity:10;
+ unsigned int coherency_line_size :12;
+ unsigned int physical_line_partition :10;
+ unsigned int ways_of_associativity :10;
} split;
u32 full;
};

union _cpuid4_leaf_ecx {
struct {
- unsigned int number_of_sets:32;
+ unsigned int number_of_sets :32;
} split;
u32 full;
};
@@ -93,60 +93,59 @@ static const enum cache_type cache_type_map[] = {

union l1_cache {
struct {
- unsigned line_size:8;
- unsigned lines_per_tag:8;
- unsigned assoc:8;
- unsigned size_in_kb:8;
+ unsigned line_size :8;
+ unsigned lines_per_tag :8;
+ unsigned assoc :8;
+ unsigned size_in_kb :8;
};
- unsigned val;
+ unsigned int val;
};

union l2_cache {
struct {
- unsigned line_size:8;
- unsigned lines_per_tag:4;
- unsigned assoc:4;
- unsigned size_in_kb:16;
+ unsigned line_size :8;
+ unsigned lines_per_tag :4;
+ unsigned assoc :4;
+ unsigned size_in_kb :16;
};
- unsigned val;
+ unsigned int val;
};

union l3_cache {
struct {
- unsigned line_size:8;
- unsigned lines_per_tag:4;
- unsigned assoc:4;
- unsigned res:2;
- unsigned size_encoded:14;
+ unsigned line_size :8;
+ unsigned lines_per_tag :4;
+ unsigned assoc :4;
+ unsigned res :2;
+ unsigned size_encoded :14;
};
- unsigned val;
+ unsigned int val;
};

static const unsigned short assocs[] = {
- [1] = 1,
- [2] = 2,
- [4] = 4,
- [6] = 8,
- [8] = 16,
- [0xa] = 32,
- [0xb] = 48,
- [0xc] = 64,
- [0xd] = 96,
- [0xe] = 128,
- [0xf] = 0xffff /* fully associative - no way to show this currently */
+ [1] = 1,
+ [2] = 2,
+ [4] = 4,
+ [6] = 8,
+ [8] = 16,
+ [0xa] = 32,
+ [0xb] = 48,
+ [0xc] = 64,
+ [0xd] = 96,
+ [0xe] = 128,
+ [0xf] = 0xffff /* Fully associative */
};

static const unsigned char levels[] = { 1, 1, 2, 3 };
-static const unsigned char types[] = { 1, 2, 3, 3 };
+static const unsigned char types[] = { 1, 2, 3, 3 };

static void legacy_amd_cpuid4(int index, union _cpuid4_leaf_eax *eax,
union _cpuid4_leaf_ebx *ebx, union _cpuid4_leaf_ecx *ecx)
{
unsigned int dummy, line_size, lines_per_tag, assoc, size_in_kb;
- union l1_cache l1i, l1d;
+ union l1_cache l1i, l1d, *l1;
union l2_cache l2;
union l3_cache l3;
- union l1_cache *l1 = &l1d;

eax->full = 0;
ebx->full = 0;
@@ -155,6 +154,7 @@ static void legacy_amd_cpuid4(int index, union _cpuid4_leaf_eax *eax,
cpuid(0x80000005, &dummy, &dummy, &l1d.val, &l1i.val);
cpuid(0x80000006, &dummy, &dummy, &l2.val, &l3.val);

+ l1 = &l1d;
switch (index) {
case 1:
l1 = &l1i;
@@ -162,48 +162,52 @@ static void legacy_amd_cpuid4(int index, union _cpuid4_leaf_eax *eax,
case 0:
if (!l1->val)
return;
- assoc = assocs[l1->assoc];
- line_size = l1->line_size;
- lines_per_tag = l1->lines_per_tag;
- size_in_kb = l1->size_in_kb;
+
+ assoc = assocs[l1->assoc];
+ line_size = l1->line_size;
+ lines_per_tag = l1->lines_per_tag;
+ size_in_kb = l1->size_in_kb;
break;
case 2:
if (!l2.val)
return;
- assoc = assocs[l2.assoc];
- line_size = l2.line_size;
- lines_per_tag = l2.lines_per_tag;
- /* cpu_data has errata corrections for K7 applied */
- size_in_kb = __this_cpu_read(cpu_info.x86_cache_size);
+
+ /* Use x86_cache_size as it might have K7 errata fixes */
+ assoc = assocs[l2.assoc];
+ line_size = l2.line_size;
+ lines_per_tag = l2.lines_per_tag;
+ size_in_kb = __this_cpu_read(cpu_info.x86_cache_size);
break;
case 3:
if (!l3.val)
return;
- assoc = assocs[l3.assoc];
- line_size = l3.line_size;
- lines_per_tag = l3.lines_per_tag;
- size_in_kb = l3.size_encoded * 512;
+
+ assoc = assocs[l3.assoc];
+ line_size = l3.line_size;
+ lines_per_tag = l3.lines_per_tag;
+ size_in_kb = l3.size_encoded * 512;
if (boot_cpu_has(X86_FEATURE_AMD_DCM)) {
- size_in_kb = size_in_kb >> 1;
- assoc = assoc >> 1;
+ size_in_kb = size_in_kb >> 1;
+ assoc = assoc >> 1;
}
break;
default:
return;
}

- eax->split.is_self_initializing = 1;
- eax->split.type = types[index];
- eax->split.level = levels[index];
- eax->split.num_threads_sharing = 0;
- eax->split.num_cores_on_die = topology_num_cores_per_package();
+ eax->split.is_self_initializing = 1;
+ eax->split.type = types[index];
+ eax->split.level = levels[index];
+ eax->split.num_threads_sharing = 0;
+ eax->split.num_cores_on_die = topology_num_cores_per_package();

if (assoc == 0xffff)
eax->split.is_fully_associative = 1;
- ebx->split.coherency_line_size = line_size - 1;
- ebx->split.ways_of_associativity = assoc - 1;
- ebx->split.physical_line_partition = lines_per_tag - 1;
- ecx->split.number_of_sets = (size_in_kb * 1024) / line_size /
+
+ ebx->split.coherency_line_size = line_size - 1;
+ ebx->split.ways_of_associativity = assoc - 1;
+ ebx->split.physical_line_partition = lines_per_tag - 1;
+ ecx->split.number_of_sets = (size_in_kb * 1024) / line_size /
(ebx->split.ways_of_associativity + 1) - 1;
}

@@ -260,18 +264,14 @@ static int fill_cpuid4_info(int index, struct _cpuid4_info *id4)

static int find_num_cache_leaves(struct cpuinfo_x86 *c)
{
- unsigned int eax, ebx, ecx, edx, op;
- union _cpuid4_leaf_eax cache_eax;
- int i = -1;
-
- if (x86_vendor_amd_or_hygon(c->x86_vendor))
- op = 0x8000001d;
- else
- op = 4;
+ unsigned int eax, ebx, ecx, edx, op;
+ union _cpuid4_leaf_eax cache_eax;
+ int i = -1;

+ /* Do a CPUID(op) loop to calculate num_cache_leaves */
+ op = x86_vendor_amd_or_hygon(c->x86_vendor) ? 0x8000001d : 4;
do {
++i;
- /* Do cpuid(op) loop to find out num_cache_leaves */
cpuid_count(op, i, &eax, &ebx, &ecx, &edx);
cache_eax.full = eax;
} while (cache_eax.split.type != CTYPE_NULL);
@@ -309,9 +309,9 @@ void cacheinfo_amd_init_llc_id(struct cpuinfo_x86 *c, u16 die_id)
num_sharing_cache = ((eax >> 14) & 0xfff) + 1;

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

- c->topo.llc_id = c->topo.apicid >> bits;
+ c->topo.llc_id = c->topo.apicid >> index_msb;
}
}
}
@@ -332,14 +332,10 @@ void init_amd_cacheinfo(struct cpuinfo_x86 *c)
{
struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);

- if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
+ if (boot_cpu_has(X86_FEATURE_TOPOEXT))
ci->num_leaves = find_num_cache_leaves(c);
- } else if (c->extended_cpuid_level >= 0x80000006) {
- if (cpuid_edx(0x80000006) & 0xf000)
- ci->num_leaves = 4;
- else
- ci->num_leaves = 3;
- }
+ else if (c->extended_cpuid_level >= 0x80000006)
+ ci->num_leaves = (cpuid_edx(0x80000006) & 0xf000) ? 4 : 3;
}

void init_hygon_cacheinfo(struct cpuinfo_x86 *c)
@@ -466,6 +462,9 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
intel_cacheinfo_0x2(c);
}

+/*
+ * linux/cacheinfo.h shared_cpu_map setup, AMD/Hygon
+ */
static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
const struct _cpuid4_info *id4)
{
@@ -482,12 +481,12 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
this_cpu_ci = get_cpu_cacheinfo(i);
if (!this_cpu_ci->info_list)
continue;
+
ci = this_cpu_ci->info_list + index;
for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) {
if (!cpu_online(sibling))
continue;
- cpumask_set_cpu(sibling,
- &ci->shared_cpu_map);
+ cpumask_set_cpu(sibling, &ci->shared_cpu_map);
}
}
} else if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
@@ -513,8 +512,7 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
apicid = cpu_data(sibling).topo.apicid;
if ((apicid < first) || (apicid > last))
continue;
- cpumask_set_cpu(sibling,
- &ci->shared_cpu_map);
+ cpumask_set_cpu(sibling, &ci->shared_cpu_map);
}
}
} else
@@ -523,18 +521,22 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index,
return 1;
}

+/*
+ * linux/cacheinfo.h shared_cpu_map setup, Intel + fallback AMD/Hygon
+ */
static void __cache_cpumap_setup(unsigned int cpu, int index,
const struct _cpuid4_info *id4)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
+ struct cpuinfo_x86 *c = &cpu_data(cpu);
struct cacheinfo *ci, *sibling_ci;
unsigned long num_threads_sharing;
int index_msb, i;
- struct cpuinfo_x86 *c = &cpu_data(cpu);

- if (x86_vendor_amd_or_hygon(c->x86_vendor))
+ if (x86_vendor_amd_or_hygon(c->x86_vendor)) {
if (__cache_amd_cpumap_setup(cpu, index, id4))
return;
+ }

ci = this_cpu_ci->info_list + index;
num_threads_sharing = 1 + id4->eax.split.num_threads_sharing;
@@ -549,8 +551,10 @@ static void __cache_cpumap_setup(unsigned int cpu, int index,
if (cpu_data(i).topo.apicid >> index_msb == c->topo.apicid >> index_msb) {
struct cpu_cacheinfo *sib_cpu_ci = get_cpu_cacheinfo(i);

+ /* Skip if itself or no cacheinfo */
if (i == cpu || !sib_cpu_ci->info_list)
- continue;/* skip if itself or no cacheinfo */
+ continue;
+
sibling_ci = sib_cpu_ci->info_list + index;
cpumask_set_cpu(i, &ci->shared_cpu_map);
cpumask_set_cpu(cpu, &sibling_ci->shared_cpu_map);
@@ -584,7 +588,7 @@ int init_cache_level(unsigned int cpu)
}

/*
- * The max shared threads number comes from CPUID.4:EAX[25-14] with input
+ * The max shared threads number comes from CPUID(4) EAX[25-14] with input
* ECX as cache index. Then right shift apicid by the number's order to get
* cache id for this cache node.
*/
@@ -620,8 +624,8 @@ int populate_cache_leaves(unsigned int cpu)
ci_info_init(ci++, &id4, nb);
__cache_cpumap_setup(cpu, idx, &id4);
}
- this_cpu_ci->cpu_map_populated = true;

+ this_cpu_ci->cpu_map_populated = true;
return 0;
}

@@ -653,12 +657,10 @@ void cache_disable(void) __acquires(cache_disable_lock)
unsigned long cr0;

/*
- * Note that this is not ideal
- * since the cache is only flushed/disabled for this CPU while the
- * MTRRs are changed, but changing this requires more invasive
- * changes to the way the kernel boots
+ * This is not ideal since the cache is only flushed/disabled
+ * for this CPU while the MTRRs are changed, but changing this
+ * requires more invasive changes to the way the kernel boots.
*/
-
raw_spin_lock(&cache_disable_lock);

/* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */
--
2.48.1