[PATCH 4.14 40/46] x86/cpu: Add a steppings field to struct x86_cpu_id

Greg Kroah-Hartman
2020-06-09T18:12:42Z

From: Mark Gross <mgross@linux.intel.com>

commit e9d7144597b10ff13ff2264c059f7d4a7fbc89ac upstream

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.
tglx: Lightweight variant for backporting ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/cpu_device_id.h | 27 +++++++++++++++++++++++++++
arch/x86/kernel/cpu/match.c | 7 ++++++-
include/linux/mod_devicetable.h | 6 ++++++
3 files changed, 39 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -9,6 +9,33 @@

#include <linux/mod_devicetable.h>

+#define X86_STEPPINGS(mins, maxs) GENMASK(maxs, mins)
+
+/**
+ * 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
+ * etc. is casted to unsigned long internally.
+ *
+ * Backport version to keep the SRBDS pile consistant. No shorter variants
+ * required for this.
+ */
+#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 \
+}
+
extern const struct x86_cpu_id *x86_match_cpu(const struct x86_cpu_id *match);

#endif
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -34,13 +34,18 @@ const struct x86_cpu_id *x86_match_cpu(c
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_stepping) & m->steppings))
+ continue;
if (m->feature != X86_FEATURE_ANY && !cpu_has(c, m->feature))
continue;
return m;
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -589,6 +589,10 @@ struct mips_cdmm_device_id {
/*
* MODULE_DEVICE_TABLE expects this struct to be called x86cpu_device_id.
* Although gcc seems to ignore this error, clang fails without this define.
+ *
+ * Note: The ordering of the struct is different from upstream because the
+ * static initializers in kernels < 5.7 still use C89 style while upstream
+ * has been converted to proper C99 initializers.
*/
#define x86cpu_device_id x86_cpu_id
struct x86_cpu_id {
@@ -597,6 +601,7 @@ struct x86_cpu_id {
__u16 model;
__u16 feature; /* bit index */
kernel_ulong_t driver_data;
+ __u16 steppings;
};

#define X86_FEATURE_MATCH(x) \
@@ -605,6 +610,7 @@ 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 */

/*