[PATCH x86 for review III] [18/29] i386: Add L3 cache support to AMD CPUID4 emulation

From: Andi Kleen
Date: Mon Feb 12 2007 - 11:53:05 EST



With that an L3 cache is correctly reported in the cache information in /sys

Signed-off-by: Andi Kleen <ak@xxxxxxx>

---
arch/i386/kernel/cpu/intel_cacheinfo.c | 65 +++++++++++++++++++++++++--------
1 file changed, 50 insertions(+), 15 deletions(-)

Index: linux/arch/i386/kernel/cpu/intel_cacheinfo.c
===================================================================
--- linux.orig/arch/i386/kernel/cpu/intel_cacheinfo.c
+++ linux/arch/i386/kernel/cpu/intel_cacheinfo.c
@@ -135,7 +135,7 @@ unsigned short num_cache_leaves;

/* AMD doesn't have CPUID4. Emulate it here to report the same
information to the user. This makes some assumptions about the machine:
- No L3, L2 not shared, no SMT etc. that is currently true on AMD CPUs.
+ L2 not shared, no SMT etc. that is currently true on AMD CPUs.

In theory the TLBs could be reported as fake type (they are in "dummy").
Maybe later */
@@ -159,11 +159,23 @@ union l2_cache {
unsigned 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 val;
+};
+
static const unsigned short assocs[] = {
[1] = 1, [2] = 2, [4] = 4, [6] = 8,
[8] = 16,
[0xf] = 0xffff // ??
- };
+};
+
static const unsigned char levels[] = { 1, 1, 2 };
static const unsigned char types[] = { 1, 2, 3 };

@@ -175,37 +187,60 @@ static void __cpuinit amd_cpuid4(int lea
unsigned line_size, lines_per_tag, assoc, size_in_kb;
union l1_cache l1i, l1d;
union l2_cache l2;
+ union l3_cache l3;
+ union l1_cache *l1 = &l1d;

eax->full = 0;
ebx->full = 0;
ecx->full = 0;

cpuid(0x80000005, &dummy, &dummy, &l1d.val, &l1i.val);
- cpuid(0x80000006, &dummy, &dummy, &l2.val, &dummy);
-
- if (leaf > 2 || !l1d.val || !l1i.val || !l2.val)
- return;
+ cpuid(0x80000006, &dummy, &dummy, &l2.val, &l3.val);

- eax->split.is_self_initializing = 1;
- eax->split.type = types[leaf];
- eax->split.level = levels[leaf];
- eax->split.num_threads_sharing = 0;
- eax->split.num_cores_on_die = current_cpu_data.x86_max_cores - 1;
-
- if (leaf <= 1) {
- union l1_cache *l1 = leaf == 0 ? &l1d : &l1i;
+ switch (leaf) {
+ case 1:
+ l1 = &l1i;
+ case 0:
+ if (!l1->val)
+ return;
assoc = l1->assoc;
line_size = l1->line_size;
lines_per_tag = l1->lines_per_tag;
size_in_kb = l1->size_in_kb;
- } else {
+ break;
+ case 2:
+ if (!l2.val)
+ return;
assoc = 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 = current_cpu_data.x86_cache_size;
+ break;
+ case 3:
+ if (!l3.val)
+ return;
+ assoc = l3.assoc;
+ line_size = l3.line_size;
+ lines_per_tag = l3.lines_per_tag;
+ switch (l3.size_encoded) {
+ case 4: size_in_kb = 2 * 1024; break;
+ case 8: size_in_kb = 4 * 1024; break;
+ case 12: size_in_kb = 6 * 1024; break;
+ default: size_in_kb = 0; break;
+ }
+ break;
+ default:
+ return;
}

+ eax->split.is_self_initializing = 1;
+ eax->split.type = types[leaf];
+ eax->split.level = levels[leaf];
+ eax->split.num_threads_sharing = 0;
+ eax->split.num_cores_on_die = current_cpu_data.x86_max_cores - 1;
+
+
if (assoc == 0xf)
eax->split.is_fully_associative = 1;
ebx->split.coherency_line_size = line_size - 1;
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/