linux-kernel - Re: [PATCH v8 2/2] x86/cacheinfo: Delete global num_cache

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Message-ID: <20241204143206.GAZ1Bn5jsTCvI_1ci0@fat_crate.local>
Date: Wed, 4 Dec 2024 15:32:06 +0100
From: Borislav Petkov <bp@...en8.de>
To: Ricardo Neri <ricardo.neri-calderon@...ux.intel.com>
Cc: x86@...nel.org, Andreas Herrmann <aherrmann@...e.com>,
	Catalin Marinas <catalin.marinas@....com>,
	Chen Yu <yu.c.chen@...el.com>, Len Brown <len.brown@...el.com>,
	Radu Rendec <rrendec@...hat.com>,
	Pierre Gondois <Pierre.Gondois@....com>, Pu Wen <puwen@...on.cn>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Sudeep Holla <sudeep.holla@....com>,
	Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
	Will Deacon <will@...nel.org>, Zhang Rui <rui.zhang@...el.com>,
	Nikolay Borisov <nik.borisov@...e.com>,
	Huang Ying <ying.huang@...el.com>,
	Ricardo Neri <ricardo.neri@...el.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v8 2/2] x86/cacheinfo: Delete global num_cache_leaves

On Wed, Nov 27, 2024 at 04:22:47PM -0800, Ricardo Neri wrote:
>  arch/x86/kernel/cpu/cacheinfo.c | 41 +++++++++++++++------------------
>  1 file changed, 18 insertions(+), 23 deletions(-)

Does that work too?

---
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c
index 95e38ab98a72..e6fa03ed9172 100644
--- a/arch/x86/kernel/cpu/cacheinfo.c
+++ b/arch/x86/kernel/cpu/cacheinfo.c
@@ -715,22 +715,23 @@ void cacheinfo_hygon_init_llc_id(struct cpuinfo_x86 *c)
 
 void init_amd_cacheinfo(struct cpuinfo_x86 *c)
 {
-
-	unsigned int cpu = c->cpu_index;
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
 
 	if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
-		get_cpu_cacheinfo(cpu)->num_leaves = find_num_cache_leaves(c);
+		ci->num_leaves = find_num_cache_leaves(c);
 	} else if (c->extended_cpuid_level >= 0x80000006) {
 		if (cpuid_edx(0x80000006) & 0xf000)
-			get_cpu_cacheinfo(cpu)->num_leaves = 4;
+			ci->num_leaves = 4;
 		else
-			get_cpu_cacheinfo(cpu)->num_leaves = 3;
+			ci->num_leaves = 3;
 	}
 }
 
 void init_hygon_cacheinfo(struct cpuinfo_x86 *c)
 {
-	get_cpu_cacheinfo(c->cpu_index)->num_leaves = find_num_cache_leaves(c);
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
+
+	ci->num_leaves = find_num_cache_leaves(c);
 }
 
 void init_intel_cacheinfo(struct cpuinfo_x86 *c)
@@ -740,20 +741,21 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
 	unsigned int new_l1d = 0, new_l1i = 0; /* Cache sizes from cpuid(4) */
 	unsigned int new_l2 = 0, new_l3 = 0, i; /* Cache sizes from cpuid(4) */
 	unsigned int l2_id = 0, l3_id = 0, num_threads_sharing, index_msb;
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(c->cpu_index);
 
 	if (c->cpuid_level > 3) {
 		/*
 		 * There should be at least one leaf. A non-zero value means
 		 * that the number of leaves has been initialized.
 		 */
-		if (!get_cpu_cacheinfo(c->cpu_index)->num_leaves)
-			get_cpu_cacheinfo(c->cpu_index)->num_leaves = find_num_cache_leaves(c);
+		if (!ci->num_leaves)
+			ci->num_leaves = find_num_cache_leaves(c);
 
 		/*
 		 * Whenever possible use cpuid(4), deterministic cache
 		 * parameters cpuid leaf to find the cache details
 		 */
-		for (i = 0; i < get_cpu_cacheinfo(c->cpu_index)->num_leaves; i++) {
+		for (i = 0; i < ci->num_leaves; i++) {
 			struct _cpuid4_info_regs this_leaf = {};
 			int retval;
 
@@ -789,14 +791,14 @@ void init_intel_cacheinfo(struct cpuinfo_x86 *c)
 	 * Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for
 	 * trace cache
 	 */
-	if ((!get_cpu_cacheinfo(c->cpu_index)->num_leaves || c->x86 == 15) && c->cpuid_level > 1) {
+	if ((!ci->num_leaves || c->x86 == 15) && c->cpuid_level > 1) {
 		/* supports eax=2  call */
 		int j, n;
 		unsigned int regs[4];
 		unsigned char *dp = (unsigned char *)regs;
 		int only_trace = 0;
 
-		if (get_cpu_cacheinfo(c->cpu_index)->num_leaves && c->x86 == 15)
+		if (ci->num_leaves && c->x86 == 15)
 			only_trace = 1;
 
 		/* Number of times to iterate */
@@ -990,8 +992,10 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
 
 int init_cache_level(unsigned int cpu)
 {
+	struct cpu_cacheinfo *ci = get_cpu_cacheinfo(cpu);
+
 	/* There should be at least one leaf. */
-	if (!get_cpu_cacheinfo(cpu)->num_leaves)
+	if (!ci->num_leaves)
 		return -ENOENT;
 
 	return 0;

-- 
Regards/Gruss,
    Boris.

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