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

diff --git a/arch/x86/include/asm/cpu_device_id.h b/arch/x86/include/asm/cpu_device_id.h
index 9c77dbee96a7f4293fee94aa3019ca0be226bbf2..88564bb1845f9dffd242561e1514f9366d9d9a49 100644 (file)
--- a/arch/x86/include/asm/cpu_device_id.h
+++ b/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

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index c5fb28e6451a3415a7af8576285b0a3ae633e6b9..b16bda1ffaab67278554d38b4b791da8a899f1ed 100644 (file)
--- a/arch/x86/kernel/apic/apic.c
+++ b/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),

diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index a5c28975c608ee0a62809a75d55ea95e34e36842..d21b352bcd720476cf79607b4954feac3269af0a 100644 (file)
--- 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),

diff --git a/drivers/edac/i10nm_base.c b/drivers/edac/i10nm_base.c
index 51556c72a96746c548ba0381d9a7af0dee8d195b..09bf5a3f06bfc383d4aa2f188c8771af0c739f0e 100644 (file)
--- a/drivers/edac/i10nm_base.c
+++ b/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);

diff --git a/drivers/edac/skx_base.c b/drivers/edac/skx_base.c
index 14cfd394b4696487d78bdb21ede26393ee7e1ddb..fed5ecb4b0b19b0b02e8758ae9b8aeda41752df4 100644 (file)
--- a/drivers/edac/skx_base.c
+++ b/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);

diff --git a/include/linux/mod_devicetable.h b/include/linux/mod_devicetable.h
index 4338b1b4ac444817e7a64376d49dbdd12d61106f..d67614f7b7f1724d61c855e034b9d5b9cd544772 100644 (file)
--- a/include/linux/mod_devicetable.h
+++ b/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 */
 
 /*