From: Mark Gross <mgross@linux.intel.com>
Date: Thu, 16 Apr 2020 17:23:10 +0200
Subject: x86/cpu: Add a steppings field to struct x86_cpu_id
Git-commit: e9d7144597b10ff13ff2264c059f7d4a7fbc89ac
Patch-mainline: v5.7-rc2
References: bsc#1154824 CVE-2020-0543
Intel uses the same family/model for several CPUs. Sometimes the
stepping must be checked to tell them apart.
On x86 there can be at most 16 steppings. Add a steppings bitmask to
x86_cpu_id and a X86_MATCH_VENDOR_FAMILY_MODEL_STEPPING_FEATURE macro
and support for matching against family/model/stepping.
[ bp: Massage. ]
Signed-off-by: Mark Gross <mgross@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Reviewed-by: Josh Poimboeuf <jpoimboe@redhat.com>
---
arch/x86/include/asm/cpu_device_id.h | 27 ++++++++++++++++++++++++---
arch/x86/kernel/cpu/match.c | 7 ++++++-
include/linux/mod_devicetable.h | 2 ++
3 files changed, 32 insertions(+), 4 deletions(-)
diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index cf3d621c6892..10426cd56dca 100644
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -18,12 +18,14 @@
#define X86_CENTAUR_FAM6_C7_D 0xd
#define X86_CENTAUR_FAM6_NANO 0xf
+#define X86_STEPPINGS(mins, maxs) GENMASK(maxs, mins)
/**
- * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Base macro for CPU matching
+ * X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE - Base macro for CPU matching
* @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
* The name is expanded to X86_VENDOR_@_vendor
* @_family: The family number or X86_FAMILY_ANY
* @_model: The model number, model constant or X86_MODEL_ANY
+ * @_steppings: Bitmask for steppings, stepping constant or X86_STEPPING_ANY
* @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
* @_data: Driver specific data or NULL. The internal storage
* format is unsigned long. The supplied value, pointer
@@ -35,16 +37,35 @@
* into another macro at the usage site for good reasons, then please
* start this local macro with X86_MATCH to allow easy grepping.
*/
-#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(_vendor, _family, _model, \
- _feature, _data) { \
- .vendor = X86_VENDOR_##_vendor, \
- .family = _family, \
- .model = _model, \
- .feature = _feature, \
- .driver_data = (unsigned long) _data \
+#define X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(_vendor, _family, _model, \
+ _steppings, _feature, _data) { \
+ .vendor = X86_VENDOR_##_vendor, \
+ .family = _family, \
+ .model = _model, \
+ .steppings = _steppings, \
+ .feature = _feature, \
+ .driver_data = (unsigned long) _data \
}
/**
+ * X86_MATCH_VENDOR_FAM_MODEL_FEATURE - Macro for CPU matching
+ * @_vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
+ * The name is expanded to X86_VENDOR_@_vendor
+ * @_family: The family number or X86_FAMILY_ANY
+ * @_model: The model number, model constant or X86_MODEL_ANY
+ * @_feature: A X86_FEATURE bit or X86_FEATURE_ANY
+ * @_data: Driver specific data or NULL. The internal storage
+ * format is unsigned long. The supplied value, pointer
+ * etc. is casted to unsigned long internally.
+ *
+ * The steppings arguments of X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE() is
+ * set to wildcards.
+ */
+#define X86_MATCH_VENDOR_FAM_MODEL_FEATURE(vendor, family, model, feature, data) \
+ X86_MATCH_VENDOR_FAM_MODEL_STEPPINGS_FEATURE(vendor, family, model, \
+ X86_STEPPING_ANY, feature, data)
+
+/**
* X86_MATCH_VENDOR_FAM_FEATURE - Macro for matching vendor, family and CPU feature
* @vendor: The vendor name, e.g. INTEL, AMD, HYGON, ..., ANY
* The name is expanded to X86_VENDOR_@vendor
diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index d3482eb43ff3..ad6776081e60 100644
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -39,13 +39,18 @@ const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match)
const struct x86_cpu_id *m;
struct cpuinfo_x86 *c = &boot_cpu_data;
- for (m = match; m->vendor | m->family | m->model | m->feature; m++) {
+ for (m = match;
+ m->vendor | m->family | m->model | m->steppings | m->feature;
+ m++) {
if (m->vendor != X86_VENDOR_ANY && c->x86_vendor != m->vendor)
continue;
if (m->family != X86_FAMILY_ANY && c->x86 != m->family)
continue;
if (m->model != X86_MODEL_ANY && c->x86_model != m->model)
continue;
+ if (m->steppings != X86_STEPPING_ANY &&
+ !(BIT(c->x86_mask) & m->steppings))
+ continue;
if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
continue;
return m;
diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 4c2ddd0941a7..0754b8d71262 100644
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -663,6 +663,7 @@ struct x86_cpu_id {
__u16 vendor;
__u16 family;
__u16 model;
+ __u16 steppings;
__u16 feature; /* bit index */
kernel_ulong_t driver_data;
};
@@ -671,6 +672,7 @@ struct x86_cpu_id {
#define X86_VENDOR_ANY 0xffff
#define X86_FAMILY_ANY 0
#define X86_MODEL_ANY 0
+#define X86_STEPPING_ANY 0
#define X86_FEATURE_ANY 0 /* Same as FPU, you can't test for that */
/*