x86, cacheinfo: Fix disabling of L3 cache indices

* Correct the masks used for writing the cache index disable indices.
* Do not turn off L3 scrubber - it is not necessary.
* Make sure wbinvd is executed on the same node where the L3 is.
* Check for out-of-bounds values written to the registers.
* Make show_cache_disable hex values unambiguous
* Check for Erratum #388

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1264172467-25155-4-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 21 insertions, 13 deletions

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index fc6c8ef92dcc..08c91abc4d32 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -18,6 +18,7 @@
 #include <asm/processor.h>
 #include <linux/smp.h>
 #include <asm/k8.h>
+#include <asm/smp.h>
 
 #define LVL_1_INST      1
 #define LVL_1_DATA      2
@@ -299,8 +300,10 @@ amd_check_l3_disable(int index, struct _cpuid4_info_regs *this_leaf)
         if (boot_cpu_data.x86 == 0x11)
                 return;
 
-        /* see erratum #382 */
-        if ((boot_cpu_data.x86 == 0x10) && (boot_cpu_data.x86_model < 0x8))
+        /* see errata #382 and #388 */
+        if ((boot_cpu_data.x86 == 0x10) &&
+            ((boot_cpu_data.x86_model < 0x9) ||
+             (boot_cpu_data.x86_mask  < 0x1)))
                 return;
 
         this_leaf->can_disable = 1;
@@ -726,12 +729,12 @@ static ssize_t show_cache_disable(struct _cpuid4_info *this_leaf, char *buf,
                 return -EINVAL;
 
         pci_read_config_dword(dev, 0x1BC + index * 4, &reg);
-        return sprintf(buf, "%x\n", reg);
+        return sprintf(buf, "0x%08x\n", reg);
 }
 
 #define SHOW_CACHE_DISABLE(index)                                       \
 static ssize_t                                                          \
-show_cache_disable_##index(struct _cpuid4_info *this_leaf, char *buf)   \
+show_cache_disable_##index(struct _cpuid4_info *this_leaf, char *buf)   \
 {                                                                       \
         return show_cache_disable(this_leaf, buf, index);               \
 }
@@ -745,7 +748,9 @@ static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
         int node = cpu_to_node(cpu);
         struct pci_dev *dev = node_to_k8_nb_misc(node);
         unsigned long val = 0;
-        unsigned int scrubber = 0;
+
+#define SUBCACHE_MASK   (3UL << 20)
+#define SUBCACHE_INDEX  0xfff
 
         if (!this_leaf->can_disable)
                 return -EINVAL;
@@ -759,21 +764,24 @@ static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
         if (strict_strtoul(buf, 10, &val) < 0)
                 return -EINVAL;
 
-        val |= 0xc0000000;
-
-        pci_read_config_dword(dev, 0x58, &scrubber);
-        scrubber &= ~0x1f000000;
-        pci_write_config_dword(dev, 0x58, scrubber);
+        /* do not allow writes outside of allowed bits */
+        if (val & ~(SUBCACHE_MASK | SUBCACHE_INDEX))
+                return -EINVAL;
 
-        pci_write_config_dword(dev, 0x1BC + index * 4, val & ~0x40000000);
-        wbinvd();
+        val |= BIT(30);
         pci_write_config_dword(dev, 0x1BC + index * 4, val);
+        /*
+         * We need to WBINVD on a core on the node containing the L3 cache which
+         * indices we disable therefore a simple wbinvd() is not sufficient.
+         */
+        wbinvd_on_cpu(cpu);
+        pci_write_config_dword(dev, 0x1BC + index * 4, val | BIT(31));
         return count;
 }
 
 #define STORE_CACHE_DISABLE(index)                                      \
 static ssize_t                                                          \
-store_cache_disable_##index(struct _cpuid4_info *this_leaf,             \
+store_cache_disable_##index(struct _cpuid4_info *this_leaf,             \
                             const char *buf, size_t count)              \
 {                                                                       \
         return store_cache_disable(this_leaf, buf, count, index);       \