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Subject[PATCH 5/5] x86, cacheinfo: Calculate L3 indices
Date
From: Borislav Petkov <borislav.petkov@amd.com>

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>
---
arch/x86/kernel/cpu/intel_cacheinfo.c | 35 +++++++++++++++++++++++++++++---
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 3976ce9..589b705 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);
--
1.6.6


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