[PATCH] Conform L3 Cache Index Disable to Linux standards

[Mark Langsdorf]

The L3 Cache Index Disable feature to arch/x86/kernel/cpu/intel_cacheinfo.c
accepted in 2.6.28 was inadvertently a preliminary version of the patch
that should not have been accepted.  It did not include ABI documentation
and did not meet the usage standards of a /sys file.

This patch changes that code to use a proposed patch that had the
maintainer's approval but was accidentally not accepted.

It also corrects prevents the patch from being used on AMD processors
that do not currently support L3 Cache Index Disable.

-Mark Langsdorf
Operating System Research Center
AMD

Signed-off-by: Mark Langsdorf <mark.langsdorf@xxxxxxx>

diff -r 5fa18ea9996e Documentation/ABI/testing/sysfs-devices-cache_disable
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/Documentation/ABI/testing/sysfs-devices-cache_disable	Wed Feb 18 10:20:33 2009 -0600
@@ -0,0 +1,18 @@
+What:	    /sys/devices/system/cpu/cpu*/cache/index*/cache_disable_X
+Date:	    August 2008
+KernelVersion:  2.6.27
+Contact:	 mark.langsd...@xxxxxxx
+Description:    These files exist in every cpu's cache index directories.
+		 There are currently 2 cache_disable_# files in each
+		 directory.  Reading from these files on a supported
+		 processor will return that cache disable index value
+		 for that processor and node.  Writing to one of these
+		 files will cause the specificed cache index to be disabled.
+
+		 Currently, only AMD Family 10h Processors support cache index
+		 disable, and only for their L3 caches.  See the BIOS and
+		 Kernel Developer's Guide at
+		 http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_do...
+		 for formatting information and other details on the
+		 cache index disable.
+Users:	   joachim.degu...@xxxxxxx
diff -r 5fa18ea9996e arch/x86/kernel/cpu/intel_cacheinfo.c
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c	Wed Feb 18 10:17:56 2009 -0600
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c	Wed Feb 18 10:20:33 2009 -0600
@@ -17,6 +17,9 @@
 
 #include <asm/processor.h>
 #include <asm/smp.h>
+
+#include <linux/pci.h>
+#include <asm/k8.h>
 
 #define LVL_1_INST	1
 #define LVL_1_DATA	2
@@ -149,14 +152,6 @@ struct _cpuid4_info {
 	unsigned long can_disable;
 	cpumask_t shared_cpu_map;	/* future?: only cpus/node is needed */
 };
-
-#ifdef CONFIG_PCI
-static struct pci_device_id k8_nb_id[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, 0x1103) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, 0x1203) },
-	{}
-};
-#endif
 
 unsigned short			num_cache_leaves;
 
@@ -282,6 +277,11 @@ amd_check_l3_disable(int index, struct _
 {
 	if (index < 3)
 		return;
+	if (boot_cpu_data.x86 == 0x11)
+		return;
+	if ((boot_cpu_data.x86 == 0x10) && (boot_cpu_data.x86_model < 0x15))
+		return;
+
 	this_leaf->can_disable = 1;
 }
 
@@ -617,6 +617,66 @@ static ssize_t show_##file_name						\
 	return sprintf (buf, "%lu\n", (unsigned long)this_leaf->object + val); \
 }
 
+static ssize_t show_cache_disable(struct _cpuid4_info *this_leaf, char *buf,
+		 unsigned int index)
+{
+	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
+	struct pci_dev *dev = k8_northbridges[node];
+	unsigned int reg = 0;
+
+	if (!this_leaf->can_disable)
+		return -EINVAL;
+
+	pci_read_config_dword(dev, 0x1BC + index * 4, &reg);
+	return sprintf(buf, "%x\n", reg);
+}
+
+#define SHOW_CACHE_DISABLE(index)					\
+static ssize_t								\
+show_cache_disable_##index(struct _cpuid4_info *this_leaf, char *buf)  	\
+{									\
+	return show_cache_disable(this_leaf, buf, index);		\
+}
+
+static ssize_t
+store_cache_disable(struct _cpuid4_info *this_leaf, const char *buf,
+		 size_t count, unsigned int index)
+{
+	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
+	struct pci_dev *dev = k8_northbridges[node];
+	ssize_t ret = 0;
+	unsigned int val;
+
+	if (!this_leaf->can_disable)
+		return -EINVAL;
+
+	ret = sscanf(buf, "%x", &val);
+	if (ret != 1)
+		return -EINVAL;
+
+	if (!capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	val |= 0xc0000000;
+	pci_write_config_dword(dev, 0x1BC + index * 4, val & ~0x40000000);
+	wbinvd();
+	pci_write_config_dword(dev, 0x1BC + index * 4, val);
+	return count;
+}
+
+#define STORE_CACHE_DISABLE(index)					\
+static ssize_t								\
+store_cache_disable_##index(struct _cpuid4_info *this_leaf,	     	\
+		 const char *buf, size_t count)			     	\
+{									\
+	return store_cache_disable(this_leaf, buf, count, index);	\
+}
+
+SHOW_CACHE_DISABLE(0)
+STORE_CACHE_DISABLE(0)
+SHOW_CACHE_DISABLE(1)
+STORE_CACHE_DISABLE(1)
+
 show_one_plus(level, eax.split.level, 0);
 show_one_plus(coherency_line_size, ebx.split.coherency_line_size, 1);
 show_one_plus(physical_line_partition, ebx.split.physical_line_partition, 1);
@@ -673,96 +733,6 @@ static ssize_t show_type(struct _cpuid4_
 #define to_object(k)	container_of(k, struct _index_kobject, kobj)
 #define to_attr(a)	container_of(a, struct _cache_attr, attr)
 
-#ifdef CONFIG_PCI
-static struct pci_dev *get_k8_northbridge(int node)
-{
-	struct pci_dev *dev = NULL;
-	int i;
-
-	for (i = 0; i <= node; i++) {
-		do {
-			dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
-			if (!dev)
-				break;
-		} while (!pci_match_id(&k8_nb_id[0], dev));
-		if (!dev)
-			break;
-	}
-	return dev;
-}
-#else
-static struct pci_dev *get_k8_northbridge(int node)
-{
-	return NULL;
-}
-#endif
-
-static ssize_t show_cache_disable(struct _cpuid4_info *this_leaf, char *buf)
-{
-	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
-	struct pci_dev *dev = NULL;
-	ssize_t ret = 0;
-	int i;
-
-	if (!this_leaf->can_disable)
-		return sprintf(buf, "Feature not enabled\n");
-
-	dev = get_k8_northbridge(node);
-	if (!dev) {
-		printk(KERN_ERR "Attempting AMD northbridge operation on a system with no northbridge\n");
-		return -EINVAL;
-	}
-
-	for (i = 0; i < 2; i++) {
-		unsigned int reg;
-
-		pci_read_config_dword(dev, 0x1BC + i * 4, &reg);
-
-		ret += sprintf(buf, "%sEntry: %d\n", buf, i);
-		ret += sprintf(buf, "%sReads:  %s\tNew Entries: %s\n",  
-			buf,
-			reg & 0x80000000 ? "Disabled" : "Allowed",
-			reg & 0x40000000 ? "Disabled" : "Allowed");
-		ret += sprintf(buf, "%sSubCache: %x\tIndex: %x\n",
-			buf, (reg & 0x30000) >> 16, reg & 0xfff);
-	}
-	return ret;
-}
-
-static ssize_t
-store_cache_disable(struct _cpuid4_info *this_leaf, const char *buf,
-		    size_t count)
-{
-	int node = cpu_to_node(first_cpu(this_leaf->shared_cpu_map));
-	struct pci_dev *dev = NULL;
-	unsigned int ret, index, val;
-
-	if (!this_leaf->can_disable)
-		return 0;
-
-	if (strlen(buf) > 15)
-		return -EINVAL;
-
-	ret = sscanf(buf, "%x %x", &index, &val);
-	if (ret != 2)
-		return -EINVAL;
-	if (index > 1)
-		return -EINVAL;
-
-	val |= 0xc0000000;
-	dev = get_k8_northbridge(node);
-	if (!dev) {
-		printk(KERN_ERR "Attempting AMD northbridge operation on a system with no northbridge\n");
-		return -EINVAL;
-	}
-
-	pci_write_config_dword(dev, 0x1BC + index * 4, val & ~0x40000000);
-	wbinvd();
-	pci_write_config_dword(dev, 0x1BC + index * 4, val);
-
-	return 1;
-}
-
 struct _cache_attr {
 	struct attribute attr;
 	ssize_t (*show)(struct _cpuid4_info *, char *);
@@ -783,7 +753,11 @@ define_one_ro(shared_cpu_map);
 define_one_ro(shared_cpu_map);
 define_one_ro(shared_cpu_list);
 
-static struct _cache_attr cache_disable = __ATTR(cache_disable, 0644, show_cache_disable, store_cache_disable);
+static struct _cache_attr cache_disable_0 = __ATTR(cache_disable_0, 0644,
+		 show_cache_disable_0, store_cache_disable_0);
+static struct _cache_attr cache_disable_1 = __ATTR(cache_disable_1, 0644,
+		 show_cache_disable_1, store_cache_disable_1);
+
 
 static struct attribute * default_attrs[] = {
 	&type.attr,
@@ -795,7 +769,8 @@ static struct attribute * default_attrs[
 	&size.attr,
 	&shared_cpu_map.attr,
 	&shared_cpu_list.attr,
-	&cache_disable.attr,
+	&cache_disable_0.attr,
+	&cache_disable_1.attr,
 	NULL
 };
 

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