[PATCH v3 29/29] x86/cacheinfo: Apply maintainer-tip coding style fixes
From: Ahmed S. Darwish
Date: Wed Mar 19 2025 - 08:28:46 EST
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 Documentation/process/maintainer-tip.rst coding style fixes to the
rest of the code, and align its assignment expressions for readability.
Standardize on CPUID(n) when mentioning leaf queries.
Avoid breaking long lines when doing so helps 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@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/cacheinfo.c | 215 ++++++++++++++++----------------
1 file changed, 107 insertions(+), 108 deletions(-)
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 71587570705f..cd48d34ac04b 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@xxxxxxxxx>: 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@xxxxxxxxx>: 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;
}
@@ -262,19 +266,14 @@ 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 (c->x86_vendor == X86_VENDOR_AMD ||
- c->x86_vendor == X86_VENDOR_HYGON)
- 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 = (c->x86_vendor == X86_VENDOR_AMD || c->x86_vendor == X86_VENDOR_HYGON) ? 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);
@@ -312,9 +311,9 @@ 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;
}
}
}
@@ -335,14 +334,10 @@ 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)
@@ -469,6 +464,9 @@ 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)
{
@@ -485,12 +483,12 @@ 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)) {
@@ -516,8 +514,7 @@ 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
@@ -526,17 +523,19 @@ 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 (c->x86_vendor == X86_VENDOR_AMD ||
- c->x86_vendor == X86_VENDOR_HYGON) {
+ if (c->x86_vendor == X86_VENDOR_AMD || c->x86_vendor == X86_VENDOR_HYGON) {
if (__cache_amd_cpumap_setup(cpu, index, id4))
return;
}
@@ -554,8 +553,10 @@ 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);
@@ -589,7 +590,7 @@ 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.
*/
@@ -626,8 +627,8 @@ 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;
}
@@ -659,12 +660,10 @@ 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