x86/cpu: Add a steppings field to struct x86_cpu_id

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: Ben Hutchings <ben@decadent.org.uk>

diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index ff501e511d91f5648ac003d3a0537ddebe4bb982..b9473858c6b6d0f5e537c53d14dd85167f007112 100644 (file)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/arch/x86/include/asm/cpu_device_id.h
@@ -8,6 +8,33 @@
 
 #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

diff --git a/arch/x86/kernel/cpu/match.c b/arch/x86/kernel/cpu/match.c
index fbb5e90557a5257bbde11179cdeb415e60485019..a207aaaf78db5900432739448eb3e069c971213b 100644 (file)
--- a/arch/x86/kernel/cpu/match.c
+++ b/arch/x86/kernel/cpu/match.c
@@ -33,13 +33,18 @@ 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_stepping) & 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 4c546028b035d4f1dd94b0fbdf31a497d7502258..db45b2a21d2fcc10cd1cda56563afa2fd2b5eb82 100644 (file)
--- a/include/linux/mod_devicetable.h
+++ b/include/linux/mod_devicetable.h
@@ -559,6 +559,10 @@ struct amba_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 {
@@ -567,6 +571,7 @@ struct x86_cpu_id {
        __u16 model;
        __u16 feature;  /* bit index */
        kernel_ulong_t driver_data;
+       __u16 steppings;
 };
 
 #define X86_FEATURE_MATCH(x) \
@@ -575,6 +580,7 @@ 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 */
 
 /*