From: Shaohua Li <shaohua.li@intel.com>
Date: Mon, 27 Mar 2006 09:15:24 +0000 (-0800)
Subject: [PATCH] x86: don't use cpuid.2 to determine cache info if cpuid.4 is supported
X-Git-Tag: v2.6.17-rc1~418
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b06be912a3ad68c69dba0ed6e92723140020e392;p=linux-2.6

[PATCH] x86: don't use cpuid.2 to determine cache info if cpuid.4 is supported

Don't use cpuid.2 to determine cache info if cpuid.4 is supported.  The
exception is P4 trace cache.  We always use cpuid.2 to get trace cache
under P4.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/arch/i386/kernel/cpu/intel_cacheinfo.c b/arch/i386/kernel/cpu/intel_cacheinfo.c
index 7e7fd4e67d..9df87b0361 100644
--- a/arch/i386/kernel/cpu/intel_cacheinfo.c
+++ b/arch/i386/kernel/cpu/intel_cacheinfo.c
@@ -225,11 +225,19 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 			}
 		}
 	}
-	if (c->cpuid_level > 1) {
+	/*
+	 * Don't use cpuid2 if cpuid4 is supported. For P4, we use cpuid2 for
+	 * trace cache
+	 */
+	if ((num_cache_leaves == 0 || c->x86 == 15) && c->cpuid_level > 1) {
 		/* supports eax=2  call */
 		int i, j, n;
 		int regs[4];
 		unsigned char *dp = (unsigned char *)regs;
+		int only_trace = 0;
+
+		if (num_cache_leaves != 0 && c->x86 == 15)
+			only_trace = 1;
 
 		/* Number of times to iterate */
 		n = cpuid_eax(2) & 0xFF;
@@ -251,6 +259,8 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 				while (cache_table[k].descriptor != 0)
 				{
 					if (cache_table[k].descriptor == des) {
+						if (only_trace && cache_table[k].cache_type != LVL_TRACE)
+							break;
 						switch (cache_table[k].cache_type) {
 						case LVL_1_INST:
 							l1i += cache_table[k].size;
@@ -276,43 +286,46 @@ unsigned int __cpuinit init_intel_cacheinfo(struct cpuinfo_x86 *c)
 				}
 			}
 		}
+	}
 
-		if (new_l1d)
-			l1d = new_l1d;
+	if (new_l1d)
+		l1d = new_l1d;
 
-		if (new_l1i)
-			l1i = new_l1i;
+	if (new_l1i)
+		l1i = new_l1i;
 
-		if (new_l2) {
-			l2 = new_l2;
+	if (new_l2) {
+		l2 = new_l2;
 #ifdef CONFIG_SMP
-			cpu_llc_id[cpu] = l2_id;
+		cpu_llc_id[cpu] = l2_id;
 #endif
-		}
+	}
 
-		if (new_l3) {
-			l3 = new_l3;
+	if (new_l3) {
+		l3 = new_l3;
 #ifdef CONFIG_SMP
-			cpu_llc_id[cpu] = l3_id;
+		cpu_llc_id[cpu] = l3_id;
 #endif
-		}
-
-		if ( trace )
-			printk (KERN_INFO "CPU: Trace cache: %dK uops", trace);
-		else if ( l1i )
-			printk (KERN_INFO "CPU: L1 I cache: %dK", l1i);
-		if ( l1d )
-			printk(", L1 D cache: %dK\n", l1d);
-		else
-			printk("\n");
-		if ( l2 )
-			printk(KERN_INFO "CPU: L2 cache: %dK\n", l2);
-		if ( l3 )
-			printk(KERN_INFO "CPU: L3 cache: %dK\n", l3);
-
-		c->x86_cache_size = l3 ? l3 : (l2 ? l2 : (l1i+l1d));
 	}
 
+	if (trace)
+		printk (KERN_INFO "CPU: Trace cache: %dK uops", trace);
+	else if ( l1i )
+		printk (KERN_INFO "CPU: L1 I cache: %dK", l1i);
+
+	if (l1d)
+		printk(", L1 D cache: %dK\n", l1d);
+	else
+		printk("\n");
+
+	if (l2)
+		printk(KERN_INFO "CPU: L2 cache: %dK\n", l2);
+
+	if (l3)
+		printk(KERN_INFO "CPU: L3 cache: %dK\n", l3);
+
+	c->x86_cache_size = l3 ? l3 : (l2 ? l2 : (l1i+l1d));
+
 	return l2;
 }