x86, cacheinfo: Calculate L3 indices

We need to know the valid L3 indices interval when disabling them over
/sysfs. Do that when the core is brought online and add boundary checks
to the sysfs .store attribute.

Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <1264172467-25155-6-git-send-email-bp@amd64.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

1 files changed, 31 insertions, 4 deletions

diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index 3976ce95095f..589b705e80ed 100644
--- a/arch/x86/kernel/cpu/intel_cacheinfo.c
+++ b/arch/x86/kernel/cpu/intel_cacheinfo.c
@@ -151,7 +151,8 @@ struct _cpuid4_info {
         union _cpuid4_leaf_ebx ebx;
         union _cpuid4_leaf_ecx ecx;
         unsigned long size;
-        unsigned long can_disable;
+        bool can_disable;
+        unsigned int l3_indices;
         DECLARE_BITMAP(shared_cpu_map, NR_CPUS);
 };
 
@@ -161,7 +162,8 @@ struct _cpuid4_info_regs {
         union _cpuid4_leaf_ebx ebx;
         union _cpuid4_leaf_ecx ecx;
         unsigned long size;
-        unsigned long can_disable;
+        bool can_disable;
+        unsigned int l3_indices;
 };
 
 unsigned short                  num_cache_leaves;
@@ -291,6 +293,29 @@ amd_cpuid4(int leaf, union _cpuid4_leaf_eax *eax,
                 (ebx->split.ways_of_associativity + 1) - 1;
 }
 
+static unsigned int __cpuinit amd_calc_l3_indices(void)
+{
+        /*
+         * We're called over smp_call_function_single() and therefore
+         * are on the correct cpu.
+         */
+        int cpu = smp_processor_id();
+        int node = cpu_to_node(cpu);
+        struct pci_dev *dev = node_to_k8_nb_misc(node);
+        unsigned int sc0, sc1, sc2, sc3;
+        u32 val;
+
+        pci_read_config_dword(dev, 0x1C4, &val);
+
+        /* calculate subcache sizes */
+        sc0 = !(val & BIT(0));
+        sc1 = !(val & BIT(4));
+        sc2 = !(val & BIT(8))  + !(val & BIT(9));
+        sc3 = !(val & BIT(12)) + !(val & BIT(13));
+
+        return (max(max(max(sc0, sc1), sc2), sc3) << 10) - 1;
+}
+
 static void __cpuinit
 amd_check_l3_disable(int index, struct _cpuid4_info_regs *this_leaf)
 {
@@ -306,7 +331,8 @@ amd_check_l3_disable(int index, struct _cpuid4_info_regs *this_leaf)
              (boot_cpu_data.x86_mask  < 0x1)))
                 return;
 
-        this_leaf->can_disable = 1;
+        this_leaf->can_disable = true;
+        this_leaf->l3_indices  = amd_calc_l3_indices();
 }
 
 static int
@@ -765,7 +791,8 @@ static ssize_t store_cache_disable(struct _cpuid4_info *this_leaf,
                 return -EINVAL;
 
         /* do not allow writes outside of allowed bits */
-        if (val & ~(SUBCACHE_MASK | SUBCACHE_INDEX))
+        if ((val & ~(SUBCACHE_MASK | SUBCACHE_INDEX)) ||
+            ((val & SUBCACHE_INDEX) > this_leaf->l3_indices))
                 return -EINVAL;
 
         val |= BIT(30);