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 <mingo@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20241213185129.65527B2A%40davehans-spike.ostc.intel.com

1 files changed, 39 insertions, 39 deletions

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a5c28975c608..d21b352bcd72 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/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),