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Subject[PATCH 5/7] x86, cacheinfo: Fix disabling of L3 cache indices
Date
From: Borislav Petkov <borislav.petkov@amd.com>

* 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>
---
arch/x86/kernel/cpu/intel_cacheinfo.c | 30 +++++++++++++++++-------------
1 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c
index fc6c8ef..cef4fdd 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 +764,20 @@ 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);
+ 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); \
--
1.6.6


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