Message-ID: <20250317164745.4754-30-darwi@linutronix.de>
Date: Mon, 17 Mar 2025 17:47:45 +0100
From: "Ahmed S. Darwish" <darwi@...utronix.de>
To: Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Borislav Petkov <bp@...en8.de>
Cc: Thomas Gleixner <tglx@...utronix.de>,
	Andrew Cooper <andrew.cooper3@...rix.com>,
	"H. Peter Anvin" <hpa@...or.com>,
	John Ogness <john.ogness@...utronix.de>,
	x86@...nel.org,
	x86-cpuid@...ts.linux.dev,
	LKML <linux-kernel@...r.kernel.org>,
	"Ahmed S. Darwish" <darwi@...utronix.de>
Subject: [PATCH v2 29/29] x86/cacheinfo: Apply maintainer-tip coding style fixes

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@...utronix.de>
---
 arch/x86/kernel/cpu/cacheinfo.c | 211 ++++++++++++++++----------------
 1 file changed, 106 insertions(+), 105 deletions(-)

diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 397c3dbc5851..ad0d1b0445b0 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@...el.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@...el.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
@@ -523,14 +521,17 @@ 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 (__cache_amd_cpumap_setup(cpu, index, id4))
@@ -550,8 +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);
@@ -585,7 +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.
  */
@@ -621,8 +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;
 }
 
@@ -654,12 +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

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