[PATCH v3] Fix missing L2 cache size in /sys/devices/system/cpu
olson at cumulusnetworks.com
olson at cumulusnetworks.com
Thu Feb 26 11:04:47 AEDT 2015
From: Dave Olson <olson at cumulusnetworks.com>
This problem appears to have been introduced in 2.6.29 by
93197a36a9c16a85fb24cf5a8639f7bf9af838a3.
This caused lscpu to error out on e500v2 devices, and probably others
error: cannot open /sys/devices/system/cpu/cpu0/cache/index2/size: No such file or directory
Some embedded powerpc systems use cache-size in DTS for the unified L2 cache
size, not d-cache-size, so we need to allow for both DTS names. Added a
new CACHE_TYPE_UNIFIED_D cache_type_info structure to handle this.
This patch is against git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc.git
next branch. It is the same as the v2 patch, but against next, rather than master.
I can rebase, if desired.
Signed-off-by: Dave Olson <olson at cumulusnetworks.com>
---
arch/powerpc/kernel/cacheinfo.c | 38 ++++++++++++++++++++++++++++++++++----
1 file changed, 34 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/kernel/cacheinfo.c b/arch/powerpc/kernel/cacheinfo.c
index ae77b7e..860ed54 100644
--- a/arch/powerpc/kernel/cacheinfo.c
+++ b/arch/powerpc/kernel/cacheinfo.c
@@ -61,12 +61,22 @@ struct cache_type_info {
};
/* These are used to index the cache_type_info array. */
-#define CACHE_TYPE_UNIFIED 0
-#define CACHE_TYPE_INSTRUCTION 1
-#define CACHE_TYPE_DATA 2
+#define CACHE_TYPE_UNIFIED 0 /* cache-size, cache-block-size, etc. */
+#define CACHE_TYPE_UNIFIED_D 1 /* d-cache-size, d-cache-block-size, etc */
+#define CACHE_TYPE_INSTRUCTION 2
+#define CACHE_TYPE_DATA 3
static const struct cache_type_info cache_type_info[] = {
{
+ /* Embedded systems that use cache-size, cache-block-size,
+ * etc. for the Unified (typically L2) cache. */
+ .name = "Unified",
+ .size_prop = "cache-size",
+ .line_size_props = { "cache-line-size",
+ "cache-block-size", },
+ .nr_sets_prop = "cache-sets",
+ },
+ {
/* PowerPC Processor binding says the [di]-cache-*
* must be equal on unified caches, so just use
* d-cache properties. */
@@ -293,7 +303,8 @@ static struct cache *cache_find_first_sibling(struct cache *cache)
{
struct cache *iter;
- if (cache->type == CACHE_TYPE_UNIFIED)
+ if (cache->type == CACHE_TYPE_UNIFIED ||
+ cache->type == CACHE_TYPE_UNIFIED_D)
return cache;
list_for_each_entry(iter, &cache_list, list)
@@ -324,14 +335,33 @@ static bool cache_node_is_unified(const struct device_node *np)
return of_get_property(np, "cache-unified", NULL);
}
+/*
+ * Handle unified caches that have two different types of tags. Most embedded
+ * use cache-size, etc. for the unified cache size, but open firmware systems
+ * use d-cache-size, etc. Since they all appear to be consistent, check on
+ * initialization for which type we are, and use the appropriate structure.
+ */
static struct cache *cache_do_one_devnode_unified(struct device_node *node,
int level)
{
struct cache *cache;
+ int ucache;
pr_debug("creating L%d ucache for %s\n", level, node->full_name);
cache = new_cache(CACHE_TYPE_UNIFIED, level, node);
+ if (of_get_property(node,
+ cache_type_info[CACHE_TYPE_UNIFIED_D].size_prop, NULL)) {
+ ucache = CACHE_TYPE_UNIFIED_D;
+ } else {
+ ucache = CACHE_TYPE_UNIFIED; /* assume embedded */
+ if (of_get_property(node,
+ cache_type_info[CACHE_TYPE_UNIFIED].size_prop, NULL) ==
+ NULL)
+ printk(KERN_WARNING "Unified cache property missing\n");
+ }
+
+ cache = new_cache(ucache, level, node);
return cache;
}
--
1.7.10.4
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