x86/cpu: Expose only stepping min/max interface

The x86_match_cpu() infrastructure can match CPU steppings. Since
there are only 16 possible steppings, the matching infrastructure goes
all out and stores the stepping match as a bitmap. That means it can
match any possible steppings in a single list entry. Fun.

But it exposes this bitmap to each of the X86_MATCH_*() helpers when
none of them really need a bitmap. It makes up for this by exporting a
helper (X86_STEPPINGS()) which converts a contiguous stepping range
into the bitmap which every single user leverages.

Instead of a bitmap, have the main helper for this sort of thing
(X86_MATCH_VFM_STEPS()) just take a stepping range. This ends up
actually being even more compact than before.

Leave the helper in place (renamed to __X86_STEPPINGS()) to make it
more clear what is going on instead of just having a random GENMASK()
in the middle of an already complicated macro.

One oddity that I hit was this macro:

       X86_MATCH_VFM_STEPS(vfm, X86_STEPPING_MIN, max_stepping, issues)

It *could* have been converted over to take a min/max stepping value
for each entry. But that would have been a bit too verbose and would
prevent the one oddball in the list (INTEL_COMETLAKE_L stepping 0)
from sticking out.

Instead, just have it take a *maximum* stepping and imply that the match
is from 0=>max_stepping. This is functional for all the cases now and
also retains the nice property of having INTEL_COMETLAKE_L stepping 0
stick out like a sore thumb.

skx_cpuids[] is goofy. It uses the stepping match but encodes all
possible steppings. Just use a normal, non-stepping match helper.

Suggested-by: Ingo Molnar <[email protected]>
Signed-off-by: Dave Hansen <[email protected]>
Link: https://lore.kernel.org/all/20241213185129.65527B2A%40davehans-spike.ostc.intel.com

Author: hansendc

arch/x86/include/asm/cpu_device_id.h

@@ -56,7 +56,6 @@
 /* x86_cpu_id::flags */
 #define X86_CPU_ID_FLAG_ENTRY_VALID	BIT(0)
 
-#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
@@ -208,6 +207,7 @@
 		VFM_MODEL(vfm),				\
 		X86_STEPPING_ANY, X86_FEATURE_ANY, data)
 
+#define __X86_STEPPINGS(mins, maxs)    GENMASK(maxs, mins)
 /**
  * X86_MATCH_VFM_STEPPINGS - Match encoded vendor/family/model/stepping
  * @vfm:	Encoded 8-bits each for vendor, family, model
@@ -218,12 +218,13 @@
  *
  * feature is set to wildcard
  */
-#define X86_MATCH_VFM_STEPPINGS(vfm, steppings, data)	\
-	X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(	\
-		VFM_VENDOR(vfm),			\
-		VFM_FAMILY(vfm),			\
-		VFM_MODEL(vfm),				\
-		steppings, X86_FEATURE_ANY, data)
+#define X86_MATCH_VFM_STEPS(vfm, min_step, max_step, data)	\
+	X86_MATCH_VENDORID_FAM_MODEL_STEPPINGS_FEATURE(		\
+		VFM_VENDOR(vfm),				\
+		VFM_FAMILY(vfm),				\
+		VFM_MODEL(vfm),					\
+		__X86_STEPPINGS(min_step, max_step),		\
+		X86_FEATURE_ANY, data)
 
 /**
  * X86_MATCH_VFM_FEATURE - Match encoded vendor/family/model/feature

arch/x86/kernel/apic/apic.c

@@ -509,19 +509,19 @@ static struct clock_event_device lapic_clockevent = {
 static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
 
 static const struct x86_cpu_id deadline_match[] __initconst = {
-	X86_MATCH_VFM_STEPPINGS(INTEL_HASWELL_X, X86_STEPPINGS(0x2, 0x2), 0x3a), /* EP */
-	X86_MATCH_VFM_STEPPINGS(INTEL_HASWELL_X, X86_STEPPINGS(0x4, 0x4), 0x0f), /* EX */
+	X86_MATCH_VFM_STEPS(INTEL_HASWELL_X,   0x2, 0x2, 0x3a), /* EP */
+	X86_MATCH_VFM_STEPS(INTEL_HASWELL_X,   0x4, 0x4, 0x0f), /* EX */
 
 	X86_MATCH_VFM(INTEL_BROADWELL_X,	0x0b000020),
 
-	X86_MATCH_VFM_STEPPINGS(INTEL_BROADWELL_D, X86_STEPPINGS(0x2, 0x2), 0x00000011),
-	X86_MATCH_VFM_STEPPINGS(INTEL_BROADWELL_D, X86_STEPPINGS(0x3, 0x3), 0x0700000e),
-	X86_MATCH_VFM_STEPPINGS(INTEL_BROADWELL_D, X86_STEPPINGS(0x4, 0x4), 0x0f00000c),
-	X86_MATCH_VFM_STEPPINGS(INTEL_BROADWELL_D, X86_STEPPINGS(0x5, 0x5), 0x0e000003),
+	X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x2, 0x2, 0x00000011),
+	X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x3, 0x3, 0x0700000e),
+	X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x4, 0x4, 0x0f00000c),
+	X86_MATCH_VFM_STEPS(INTEL_BROADWELL_D, 0x5, 0x5, 0x0e000003),
 
-	X86_MATCH_VFM_STEPPINGS(INTEL_SKYLAKE_X, X86_STEPPINGS(0x3, 0x3), 0x01000136),
-	X86_MATCH_VFM_STEPPINGS(INTEL_SKYLAKE_X, X86_STEPPINGS(0x4, 0x4), 0x02000014),
-	X86_MATCH_VFM_STEPPINGS(INTEL_SKYLAKE_X, X86_STEPPINGS(0x5, 0xf), 0),
+	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x3, 0x3, 0x01000136),
+	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x4, 0x4, 0x02000014),
+	X86_MATCH_VFM_STEPS(INTEL_SKYLAKE_X,   0x5, 0xf, 0),
 
 	X86_MATCH_VFM(INTEL_HASWELL,		0x22),
 	X86_MATCH_VFM(INTEL_HASWELL_L,		0x20),

arch/x86/kernel/cpu/common.c

@@ -1201,8 +1201,8 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
 #define VULNBL(vendor, family, model, blacklist)	\
 	X86_MATCH_VENDOR_FAM_MODEL(vendor, family, model, blacklist)
 
-#define VULNBL_INTEL_STEPPINGS(vfm, steppings, issues)		   \
-	X86_MATCH_VFM_STEPPINGS(vfm, steppings, issues)
+#define VULNBL_INTEL_STEPS(vfm, max_stepping, issues)		   \
+	X86_MATCH_VFM_STEPS(vfm, X86_STEP_MIN, max_stepping, issues)
 
 #define VULNBL_AMD(family, blacklist)		\
 	VULNBL(AMD, family, X86_MODEL_ANY, blacklist)
@@ -1227,43 +1227,43 @@ static const __initconst struct x86_cpu_id cpu_vuln_whitelist[] = {
 #define RFDS		BIT(7)
 
 static const struct x86_cpu_id cpu_vuln_blacklist[] __initconst = {
-	VULNBL_INTEL_STEPPINGS(INTEL_IVYBRIDGE,		X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_HASWELL,		X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_HASWELL_L,		X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_HASWELL_G,		X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_HASWELL_X,		X86_STEPPING_ANY,		MMIO),
-	VULNBL_INTEL_STEPPINGS(INTEL_BROADWELL_D,	X86_STEPPING_ANY,		MMIO),
-	VULNBL_INTEL_STEPPINGS(INTEL_BROADWELL_G,	X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_BROADWELL_X,	X86_STEPPING_ANY,		MMIO),
-	VULNBL_INTEL_STEPPINGS(INTEL_BROADWELL,		X86_STEPPING_ANY,		SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_SKYLAKE_X,		X86_STEPPING_ANY,		MMIO | RETBLEED | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_SKYLAKE_L,		X86_STEPPING_ANY,		MMIO | RETBLEED | GDS | SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_SKYLAKE,		X86_STEPPING_ANY,		MMIO | RETBLEED | GDS | SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_KABYLAKE_L,	X86_STEPPING_ANY,		MMIO | RETBLEED | GDS | SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_KABYLAKE,		X86_STEPPING_ANY,		MMIO | RETBLEED | GDS | SRBDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_CANNONLAKE_L,	X86_STEPPING_ANY,		RETBLEED),
-	VULNBL_INTEL_STEPPINGS(INTEL_ICELAKE_L,		X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RETBLEED | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ICELAKE_D,		X86_STEPPING_ANY,		MMIO | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ICELAKE_X,		X86_STEPPING_ANY,		MMIO | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_COMETLAKE,		X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RETBLEED | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_COMETLAKE_L,	X86_STEPPINGS(0x0, 0x0),	MMIO | RETBLEED),
-	VULNBL_INTEL_STEPPINGS(INTEL_COMETLAKE_L,	X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RETBLEED | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_TIGERLAKE_L,	X86_STEPPING_ANY,		GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_TIGERLAKE,		X86_STEPPING_ANY,		GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_LAKEFIELD,		X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RETBLEED),
-	VULNBL_INTEL_STEPPINGS(INTEL_ROCKETLAKE,	X86_STEPPING_ANY,		MMIO | RETBLEED | GDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ALDERLAKE,		X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ALDERLAKE_L,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_RAPTORLAKE,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_RAPTORLAKE_P,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_RAPTORLAKE_S,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_GRACEMONT,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_TREMONT,	X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_TREMONT_D,	X86_STEPPING_ANY,		MMIO | RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_TREMONT_L,	X86_STEPPING_ANY,		MMIO | MMIO_SBDS | RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_GOLDMONT,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_GOLDMONT_D,	X86_STEPPING_ANY,		RFDS),
-	VULNBL_INTEL_STEPPINGS(INTEL_ATOM_GOLDMONT_PLUS, X86_STEPPING_ANY,		RFDS),
+	VULNBL_INTEL_STEPS(INTEL_IVYBRIDGE,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_HASWELL,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_HASWELL_L,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_HASWELL_G,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_HASWELL_X,	     X86_STEP_MAX,	MMIO),
+	VULNBL_INTEL_STEPS(INTEL_BROADWELL_D,	     X86_STEP_MAX,	MMIO),
+	VULNBL_INTEL_STEPS(INTEL_BROADWELL_G,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_BROADWELL_X,	     X86_STEP_MAX,	MMIO),
+	VULNBL_INTEL_STEPS(INTEL_BROADWELL,	     X86_STEP_MAX,	SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_SKYLAKE_X,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS),
+	VULNBL_INTEL_STEPS(INTEL_SKYLAKE_L,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS | SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_SKYLAKE,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS | SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_KABYLAKE_L,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS | SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_KABYLAKE,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS | SRBDS),
+	VULNBL_INTEL_STEPS(INTEL_CANNONLAKE_L,	     X86_STEP_MAX,	RETBLEED),
+	VULNBL_INTEL_STEPS(INTEL_ICELAKE_L,	     X86_STEP_MAX,	MMIO | MMIO_SBDS | RETBLEED | GDS),
+	VULNBL_INTEL_STEPS(INTEL_ICELAKE_D,	     X86_STEP_MAX,	MMIO | GDS),
+	VULNBL_INTEL_STEPS(INTEL_ICELAKE_X,	     X86_STEP_MAX,	MMIO | GDS),
+	VULNBL_INTEL_STEPS(INTEL_COMETLAKE,	     X86_STEP_MAX,	MMIO | MMIO_SBDS | RETBLEED | GDS),
+	VULNBL_INTEL_STEPS(INTEL_COMETLAKE_L,		      0x0,	MMIO | RETBLEED),
+	VULNBL_INTEL_STEPS(INTEL_COMETLAKE_L,	     X86_STEP_MAX,	MMIO | MMIO_SBDS | RETBLEED | GDS),
+	VULNBL_INTEL_STEPS(INTEL_TIGERLAKE_L,	     X86_STEP_MAX,	GDS),
+	VULNBL_INTEL_STEPS(INTEL_TIGERLAKE,	     X86_STEP_MAX,	GDS),
+	VULNBL_INTEL_STEPS(INTEL_LAKEFIELD,	     X86_STEP_MAX,	MMIO | MMIO_SBDS | RETBLEED),
+	VULNBL_INTEL_STEPS(INTEL_ROCKETLAKE,	     X86_STEP_MAX,	MMIO | RETBLEED | GDS),
+	VULNBL_INTEL_STEPS(INTEL_ALDERLAKE,	     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ALDERLAKE_L,	     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE,	     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_P,	     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_RAPTORLAKE_S,	     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_GRACEMONT,     X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT,	     X86_STEP_MAX,	MMIO | MMIO_SBDS | RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT_D,     X86_STEP_MAX,	MMIO | RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_TREMONT_L,     X86_STEP_MAX,	MMIO | MMIO_SBDS | RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT,      X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT_D,    X86_STEP_MAX,	RFDS),
+	VULNBL_INTEL_STEPS(INTEL_ATOM_GOLDMONT_PLUS, X86_STEP_MAX,	RFDS),
 
 	VULNBL_AMD(0x15, RETBLEED),
 	VULNBL_AMD(0x16, RETBLEED),

drivers/edac/i10nm_base.c

@@ -938,16 +938,17 @@ static struct res_config gnr_cfg = {
 };
 
 static const struct x86_cpu_id i10nm_cpuids[] = {
-	X86_MATCH_VFM_STEPPINGS(INTEL_ATOM_TREMONT_D,	X86_STEPPINGS(0x0, 0x3), &i10nm_cfg0),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ATOM_TREMONT_D,	X86_STEPPINGS(0x4, 0xf), &i10nm_cfg1),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ICELAKE_X,	X86_STEPPINGS(0x0, 0x3), &i10nm_cfg0),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ICELAKE_X,	X86_STEPPINGS(0x4, 0xf), &i10nm_cfg1),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ICELAKE_D,	X86_STEPPINGS(0x0, 0xf), &i10nm_cfg1),
-	X86_MATCH_VFM_STEPPINGS(INTEL_SAPPHIRERAPIDS_X,	X86_STEPPINGS(0x0, 0xf), &spr_cfg),
-	X86_MATCH_VFM_STEPPINGS(INTEL_EMERALDRAPIDS_X,	X86_STEPPINGS(0x0, 0xf), &spr_cfg),
-	X86_MATCH_VFM_STEPPINGS(INTEL_GRANITERAPIDS_X,	X86_STEPPINGS(0x0, 0xf), &gnr_cfg),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ATOM_CRESTMONT_X,	X86_STEPPINGS(0x0, 0xf), &gnr_cfg),
-	X86_MATCH_VFM_STEPPINGS(INTEL_ATOM_CRESTMONT,	X86_STEPPINGS(0x0, 0xf), &gnr_cfg),
+	X86_MATCH_VFM_STEPS(INTEL_ATOM_TREMONT_D, X86_STEP_MIN,		 0x3, &i10nm_cfg0),
+	X86_MATCH_VFM_STEPS(INTEL_ATOM_TREMONT_D,	   0x4,	X86_STEP_MAX, &i10nm_cfg1),
+	X86_MATCH_VFM_STEPS(INTEL_ICELAKE_X,	  X86_STEP_MIN,		 0x3, &i10nm_cfg0),
+	X86_MATCH_VFM_STEPS(INTEL_ICELAKE_X,		   0x4, X86_STEP_MAX, &i10nm_cfg1),
+	X86_MATCH_VFM(	    INTEL_ICELAKE_D,				      &i10nm_cfg1),
+
+	X86_MATCH_VFM(INTEL_SAPPHIRERAPIDS_X, &spr_cfg),
+	X86_MATCH_VFM(INTEL_EMERALDRAPIDS_X,  &spr_cfg),
+	X86_MATCH_VFM(INTEL_GRANITERAPIDS_X,  &gnr_cfg),
+	X86_MATCH_VFM(INTEL_ATOM_CRESTMONT_X, &gnr_cfg),
+	X86_MATCH_VFM(INTEL_ATOM_CRESTMONT,   &gnr_cfg),
 	{}
 };
 MODULE_DEVICE_TABLE(x86cpu, i10nm_cpuids);

drivers/edac/skx_base.c

@@ -164,7 +164,7 @@ static struct res_config skx_cfg = {
 };
 
 static const struct x86_cpu_id skx_cpuids[] = {
-	X86_MATCH_VFM_STEPPINGS(INTEL_SKYLAKE_X, X86_STEPPINGS(0x0, 0xf), &skx_cfg),
+	X86_MATCH_VFM(INTEL_SKYLAKE_X, &skx_cfg),
 	{ }
 };
 MODULE_DEVICE_TABLE(x86cpu, skx_cpuids);

include/linux/mod_devicetable.h

@@ -700,6 +700,8 @@ struct x86_cpu_id {
 #define X86_FAMILY_ANY 0
 #define X86_MODEL_ANY  0
 #define X86_STEPPING_ANY 0
+#define X86_STEP_MIN 0
+#define X86_STEP_MAX 0xf
 #define X86_FEATURE_ANY 0	/* Same as FPU, you can't test for that */
 
 /*