[PATCH v3 0/4] x86/cpufeatures: Automatically generate required and disabled feature masks

[PATCH v3 0/4] x86/cpufeatures: Automatically generate required and disabled feature masks

[Xin Li (Intel)]

The x86 build process first generates required and disabled feature
masks based on current build config, and then uses these generated
masks to compile the source code. When a CPU feature is not enabled
in a build config, e.g., when CONFIG_X86_FRED=n, its feature disable
flag, i.e., DISABLE_FRED, needs to be properly defined and added to
a specific disabled CPU features mask in <asm/disabled-features.h>,
as the following patch does:
https://lore.kernel.org/all/20231205105030.8698-8-xin3.li@intel.com/.
As a result, the FRED feature bit is surely cleared in the generated
kernel binary when CONFIG_X86_FRED=n.

Recently there is another case to repeat the same exercise for the
AMD SEV-SNP CPU feature:
https://lore.kernel.org/all/20240126041126.1927228-2-michael.roth@amd.com/.
https://lore.kernel.org/all/20240126041126.1927228-23-michael.roth@amd.com/.

It was one thing when there were four of CPU feature masks, but with
over 20 it is going to cause mistakes, e.g.,
https://lore.kernel.org/lkml/aaed79d5-d683-d1bc-7ba1-b33c8d6db618@suse.com/.

We want to eliminate the stupidly repeated exercise to manually assign
features to CPU feature words through introducing an AWK script to
automatically generate a header with required and disabled CPU feature
masks based on current build config, and this patch set does that.


Changes since v2:
* Remove AWK code that generates extra debugging comments (Brian Gerst).
* Move SSE_MASK to verify_cpu.S, the only place it is used (Brian Gerst).
* Add a patch to generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the
  new AWK script (Brian Gerst).

Changes since v1:
* Keep the X86_{REQUIRED,DISABLED}_FEATURE_ prefixes solely in
  arch/x86/Kconfig.cpufeatures (Borislav Petkov).
* Explain how config option names X86_{REQUIRED,DISABLED}_FEATURE_<name>
  are formed (Borislav Petkov).
* Remove code generating unused macros {REQUIRED,DISABLED}_FEATURE(x)
  to tell if a CPU feature, e.g., X86_FEATURE_FRED, is a required or
  disabled feature for this particular compile-time configuration.


H. Peter Anvin (Intel) (2):
  x86/cpufeatures: Add {required,disabled} feature configs
  x86/cpufeatures: Generate a feature mask header based on build config

Xin Li (Intel) (2):
  x86/cpufeatures: Remove {disabled,required}-features.h
  x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

 arch/x86/Kconfig                              |   4 +-
 arch/x86/Kconfig.cpu                          |  12 +-
 arch/x86/Kconfig.cpufeatures                  | 197 ++++++++++++++++++
 arch/x86/Makefile                             |  17 +-
 arch/x86/boot/cpucheck.c                      |   3 +-
 arch/x86/boot/cpuflags.c                      |   1 -
 arch/x86/boot/mkcpustr.c                      |   3 +-
 arch/x86/include/asm/Kbuild                   |   1 +
 arch/x86/include/asm/asm-prototypes.h         |   2 +-
 arch/x86/include/asm/atomic64_32.h            |   2 +-
 arch/x86/include/asm/bitops.h                 |   4 +-
 arch/x86/include/asm/cmpxchg_32.h             |   2 +-
 arch/x86/include/asm/cpufeature.h             |  70 +------
 arch/x86/include/asm/cpufeatures.h            |   8 -
 arch/x86/include/asm/disabled-features.h      | 161 --------------
 arch/x86/include/asm/required-features.h      | 105 ----------
 arch/x86/kernel/verify_cpu.S                  |   4 +
 arch/x86/lib/Makefile                         |   2 +-
 arch/x86/lib/cmpxchg8b_emu.S                  |   2 +-
 arch/x86/tools/featuremasks.awk               |  94 +++++++++
 lib/atomic64_test.c                           |   2 +-
 tools/arch/x86/include/asm/cpufeatures.h      |   8 -
 .../arch/x86/include/asm/disabled-features.h  | 161 --------------
 .../arch/x86/include/asm/required-features.h  | 105 ----------
 tools/perf/check-headers.sh                   |   2 -
 25 files changed, 327 insertions(+), 645 deletions(-)
 create mode 100644 arch/x86/Kconfig.cpufeatures
 delete mode 100644 arch/x86/include/asm/disabled-features.h
 delete mode 100644 arch/x86/include/asm/required-features.h
 create mode 100755 arch/x86/tools/featuremasks.awk
 delete mode 100644 tools/arch/x86/include/asm/disabled-features.h
 delete mode 100644 tools/arch/x86/include/asm/required-features.h


base-commit: aedd5b6d65f7db9af616404985fc8361373690be
-- 
2.45.2

[PATCH v3 1/4] x86/cpufeatures: Add {required,disabled} feature configs

[Xin Li (Intel)]

From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Required and disabled feature masks completely rely on build configs,
i.e., once a build config is fixed, so are the feature masks. To prepare
for auto-generating a header with required and disabled feature masks
based on a build config, add feature Kconfig items:
  - X86_REQUIRED_FEATURE_x
  - X86_DISABLED_FEATURE_x
each of which may be set to "y" if and only if its preconditions from
current build config are met.

X86_CMPXCHG64 and X86_CMOV are required features, thus rename them to
X86_REQUIRED_FEATURE_CX8 and X86_REQUIRED_FEATURE_CMOV.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---

Changes since v1:
* Keep the X86_{REQUIRED,DISABLED}_FEATURE_ prefixes solely in
  arch/x86/Kconfig.cpufeatures (Borislav Petkov).
* Explain how config option names X86_{REQUIRED,DISABLED}_FEATURE_<name>
  are formed (Borislav Petkov).
---
 arch/x86/Kconfig                              |   4 +-
 arch/x86/Kconfig.cpu                          |  12 +-
 arch/x86/Kconfig.cpufeatures                  | 197 ++++++++++++++++++
 arch/x86/include/asm/asm-prototypes.h         |   2 +-
 arch/x86/include/asm/atomic64_32.h            |   2 +-
 arch/x86/include/asm/bitops.h                 |   4 +-
 arch/x86/include/asm/cmpxchg_32.h             |   2 +-
 arch/x86/include/asm/required-features.h      |   4 +-
 arch/x86/lib/Makefile                         |   2 +-
 arch/x86/lib/cmpxchg8b_emu.S                  |   2 +-
 lib/atomic64_test.c                           |   2 +-
 .../arch/x86/include/asm/required-features.h  |   4 +-
 12 files changed, 213 insertions(+), 24 deletions(-)
 create mode 100644 arch/x86/Kconfig.cpufeatures

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index e30ea4129d2c..087f36305913 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -123,7 +123,7 @@ config X86
 	select ARCH_SUPPORTS_LTO_CLANG
 	select ARCH_SUPPORTS_LTO_CLANG_THIN
 	select ARCH_USE_BUILTIN_BSWAP
-	select ARCH_USE_CMPXCHG_LOCKREF		if X86_CMPXCHG64
+	select ARCH_USE_CMPXCHG_LOCKREF		if X86_REQUIRED_FEATURE_CX8
 	select ARCH_USE_MEMTEST
 	select ARCH_USE_QUEUED_RWLOCKS
 	select ARCH_USE_QUEUED_SPINLOCKS
@@ -3091,4 +3091,6 @@ config HAVE_ATOMIC_IOMAP
 
 source "arch/x86/kvm/Kconfig"
 
+source "arch/x86/Kconfig.cpufeatures"
+
 source "arch/x86/Kconfig.assembler"
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 2a7279d80460..c439f9c61101 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -366,21 +366,11 @@ config X86_HAVE_PAE
 	def_bool y
 	depends on MCRUSOE || MEFFICEON || MCYRIXIII || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MK8 || MVIAC7 || MCORE2 || MATOM || X86_64
 
-config X86_CMPXCHG64
-	def_bool y
-	depends on X86_HAVE_PAE || M586TSC || M586MMX || MK6 || MK7
-
-# this should be set for all -march=.. options where the compiler
-# generates cmov.
-config X86_CMOV
-	def_bool y
-	depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX)
-
 config X86_MINIMUM_CPU_FAMILY
 	int
 	default "64" if X86_64
 	default "6" if X86_32 && (MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MEFFICEON || MATOM || MCORE2 || MK7 || MK8)
-	default "5" if X86_32 && X86_CMPXCHG64
+	default "5" if X86_32 && X86_REQUIRED_FEATURE_CX8
 	default "4"
 
 config X86_DEBUGCTLMSR
diff --git a/arch/x86/Kconfig.cpufeatures b/arch/x86/Kconfig.cpufeatures
new file mode 100644
index 000000000000..5ed24e45df87
--- /dev/null
+++ b/arch/x86/Kconfig.cpufeatures
@@ -0,0 +1,197 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# x86 feature bits (see arch/x86/include/asm/cpufeatures.h) that are
+# either REQUIRED to be enabled, or DISABLED (always ignored) for this
+# particular compile-time configuration.  The tests for these features
+# are turned into compile-time constants via the generated
+# <asm/featuremasks.h>.
+#
+# The naming of these variables *must* match asm/cpufeatures.h, e.g.,
+#     X86_FEATURE_ALWAYS <==> X86_REQUIRED_FEATURE_ALWAYS
+#     X86_FEATURE_FRED   <==> X86_DISABLED_FEATURE_FRED
+#
+# And these REQUIRED and DISABLED config options are manipulated in an
+# AWK script as the following example:
+#
+#                          +----------------------+
+#                          |    X86_FRED = y ?    |
+#                          +----------------------+
+#                              /             \
+#                           Y /               \ N
+#  +-------------------------------------+   +-------------------------------+
+#  | X86_DISABLED_FEATURE_FRED undefined |   | X86_DISABLED_FEATURE_FRED = y |
+#  +-------------------------------------+   +-------------------------------+
+#                                                        |
+#                                                        |
+#     +-------------------------------------------+      |
+#     | X86_FEATURE_FRED: feature word 12, bit 17 | ---->|
+#     +-------------------------------------------+      |
+#                                                        |
+#                                                        |
+#                                     +-------------------------------+
+#                                     | set bit 17 of DISABLED_MASK12 |
+#                                     +-------------------------------+
+#
+
+config X86_REQUIRED_FEATURE_ALWAYS
+	def_bool y
+
+config X86_REQUIRED_FEATURE_NOPL
+	def_bool y
+	depends on X86_64 || X86_P6_NOP
+
+config X86_REQUIRED_FEATURE_CX8
+	def_bool y
+	depends on X86_HAVE_PAE || M586TSC || M586MMX || MK6 || MK7
+
+# this should be set for all -march=.. options where the compiler
+# generates cmov.
+config X86_REQUIRED_FEATURE_CMOV
+	def_bool y
+	depends on (MK8 || MK7 || MCORE2 || MPENTIUM4 || MPENTIUMM || MPENTIUMIII || MPENTIUMII || M686 || MVIAC3_2 || MVIAC7 || MCRUSOE || MEFFICEON || X86_64 || MATOM || MGEODE_LX)
+
+# this should be set for all -march= options where the compiler
+# generates movbe.
+config X86_REQUIRED_FEATURE_MOVBE
+	def_bool y
+	depends on MATOM
+
+config X86_REQUIRED_FEATURE_CPUID
+	def_bool y
+	depends on X86_64
+
+config X86_REQUIRED_FEATURE_UP
+	def_bool y
+	depends on !SMP
+
+config X86_REQUIRED_FEATURE_FPU
+	def_bool y
+	depends on !MATH_EMULATION
+
+config X86_REQUIRED_FEATURE_PAE
+	def_bool y
+	depends on X86_64 || X86_PAE
+
+config X86_REQUIRED_FEATURE_PSE
+	def_bool y
+	depends on X86_64 && !PARAVIRT_XXL
+
+config X86_REQUIRED_FEATURE_PGE
+	def_bool y
+	depends on X86_64 && !PARAVIRT_XXL
+
+config X86_REQUIRED_FEATURE_MSR
+	def_bool y
+	depends on X86_64
+
+config X86_REQUIRED_FEATURE_FXSR
+	def_bool y
+	depends on X86_64
+
+config X86_REQUIRED_FEATURE_XMM
+	def_bool y
+	depends on X86_64
+
+config X86_REQUIRED_FEATURE_XMM2
+	def_bool y
+	depends on X86_64
+
+config X86_REQUIRED_FEATURE_LM
+	def_bool y
+	depends on X86_64
+
+config X86_DISABLED_FEATURE_UMIP
+	def_bool y
+	depends on !X86_UMIP
+
+config X86_DISABLED_FEATURE_VME
+	def_bool y
+	depends on X86_64
+
+config X86_DISABLED_FEATURE_K6_MTRR
+	def_bool y
+	depends on X86_64
+
+config X86_DISABLED_FEATURE_CYRIX_ARR
+	def_bool y
+	depends on X86_64
+
+config X86_DISABLED_FEATURE_CENTAUR_MCR
+	def_bool y
+	depends on X86_64
+
+config X86_DISABLED_FEATURE_PCID
+	def_bool y
+	depends on !X86_64
+
+config X86_DISABLED_FEATURE_PKU
+	def_bool y
+	depends on !X86_INTEL_MEMORY_PROTECTION_KEYS
+
+config X86_DISABLED_FEATURE_OSPKE
+	def_bool y
+	depends on !X86_INTEL_MEMORY_PROTECTION_KEYS
+
+config X86_DISABLED_FEATURE_LA57
+	def_bool y
+	depends on !X86_5LEVEL
+
+config X86_DISABLED_FEATURE_PTI
+	def_bool y
+	depends on !MITIGATION_PAGE_TABLE_ISOLATION
+
+config X86_DISABLED_FEATURE_RETPOLINE
+	def_bool y
+	depends on !MITIGATION_RETPOLINE
+
+config X86_DISABLED_FEATURE_RETPOLINE_LFENCE
+	def_bool y
+	depends on !MITIGATION_RETPOLINE
+
+config X86_DISABLED_FEATURE_RETHUNK
+	def_bool y
+	depends on !MITIGATION_RETHUNK
+
+config X86_DISABLED_FEATURE_UNRET
+	def_bool y
+	depends on !MITIGATION_UNRET_ENTRY
+
+config X86_DISABLED_FEATURE_CALL_DEPTH
+	def_bool y
+	depends on !MITIGATION_CALL_DEPTH_TRACKING
+
+config X86_DISABLED_FEATURE_LAM
+	def_bool y
+	depends on !ADDRESS_MASKING
+
+config X86_DISABLED_FEATURE_ENQCMD
+	def_bool y
+	depends on !INTEL_IOMMU_SVM
+
+config X86_DISABLED_FEATURE_SGX
+	def_bool y
+	depends on !X86_SGX
+
+config X86_DISABLED_FEATURE_XENPV
+	def_bool y
+	depends on !XEN_PV
+
+config X86_DISABLED_FEATURE_TDX_GUEST
+	def_bool y
+	depends on !INTEL_TDX_GUEST
+
+config X86_DISABLED_FEATURE_USER_SHSTK
+	def_bool y
+	depends on !X86_USER_SHADOW_STACK
+
+config X86_DISABLED_FEATURE_IBT
+	def_bool y
+	depends on !X86_KERNEL_IBT
+
+config X86_DISABLED_FEATURE_FRED
+	def_bool y
+	depends on !X86_FRED
+
+config X86_DISABLED_FEATURE_SEV_SNP
+	def_bool y
+	depends on !KVM_AMD_SEV
diff --git a/arch/x86/include/asm/asm-prototypes.h b/arch/x86/include/asm/asm-prototypes.h
index 25466c4d2134..7fbb52143b13 100644
--- a/arch/x86/include/asm/asm-prototypes.h
+++ b/arch/x86/include/asm/asm-prototypes.h
@@ -16,7 +16,7 @@
 #include <asm/gsseg.h>
 #include <asm/nospec-branch.h>
 
-#ifndef CONFIG_X86_CMPXCHG64
+#ifndef CONFIG_X86_REQUIRED_FEATURE_CX8
 extern void cmpxchg8b_emu(void);
 #endif
 
diff --git a/arch/x86/include/asm/atomic64_32.h b/arch/x86/include/asm/atomic64_32.h
index 8db2ec4d6cda..f3438f8709bb 100644
--- a/arch/x86/include/asm/atomic64_32.h
+++ b/arch/x86/include/asm/atomic64_32.h
@@ -48,7 +48,7 @@ static __always_inline s64 arch_atomic64_read_nonatomic(const atomic64_t *v)
 	ATOMIC64_EXPORT(atomic64_##sym)
 #endif
 
-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
 #define __alternative_atomic64(f, g, out, in...) \
 	asm volatile("call %c[func]" \
 		     : out : [func] "i" (atomic64_##g##_cx8), ## in)
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h
index b96d45944c59..ff6444311704 100644
--- a/arch/x86/include/asm/bitops.h
+++ b/arch/x86/include/asm/bitops.h
@@ -321,7 +321,7 @@ static __always_inline int variable_ffs(int x)
 	asm("bsfl %1,%0"
 	    : "=r" (r)
 	    : ASM_INPUT_RM (x), "0" (-1));
-#elif defined(CONFIG_X86_CMOV)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CMOV)
 	asm("bsfl %1,%0\n\t"
 	    "cmovzl %2,%0"
 	    : "=&r" (r) : "rm" (x), "r" (-1));
@@ -378,7 +378,7 @@ static __always_inline int fls(unsigned int x)
 	asm("bsrl %1,%0"
 	    : "=r" (r)
 	    : ASM_INPUT_RM (x), "0" (-1));
-#elif defined(CONFIG_X86_CMOV)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CMOV)
 	asm("bsrl %1,%0\n\t"
 	    "cmovzl %2,%0"
 	    : "=&r" (r) : "rm" (x), "rm" (-1));
diff --git a/arch/x86/include/asm/cmpxchg_32.h b/arch/x86/include/asm/cmpxchg_32.h
index ed2797f132ce..2d875a8dbbb2 100644
--- a/arch/x86/include/asm/cmpxchg_32.h
+++ b/arch/x86/include/asm/cmpxchg_32.h
@@ -69,7 +69,7 @@ static __always_inline bool __try_cmpxchg64_local(volatile u64 *ptr, u64 *oldp,
 	return __arch_try_cmpxchg64(ptr, oldp, new,);
 }
 
-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
 
 #define arch_cmpxchg64 __cmpxchg64
 
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
index e9187ddd3d1f..cef8104c103c 100644
--- a/arch/x86/include/asm/required-features.h
+++ b/arch/x86/include/asm/required-features.h
@@ -23,13 +23,13 @@
 # define NEED_PAE	0
 #endif
 
-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
 # define NEED_CX8	(1<<(X86_FEATURE_CX8 & 31))
 #else
 # define NEED_CX8	0
 #endif
 
-#if defined(CONFIG_X86_CMOV) || defined(CONFIG_X86_64)
+#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
 # define NEED_CMOV	(1<<(X86_FEATURE_CMOV & 31))
 #else
 # define NEED_CMOV	0
diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile
index 98583a9dbab3..9d4e96157e81 100644
--- a/arch/x86/lib/Makefile
+++ b/arch/x86/lib/Makefile
@@ -49,7 +49,7 @@ ifeq ($(CONFIG_X86_32),y)
         lib-y += string_32.o
         lib-y += memmove_32.o
         lib-y += cmpxchg8b_emu.o
-ifneq ($(CONFIG_X86_CMPXCHG64),y)
+ifneq ($(CONFIG_X86_REQUIRED_FEATURE_CX8),y)
         lib-y += atomic64_386_32.o
 endif
 else
diff --git a/arch/x86/lib/cmpxchg8b_emu.S b/arch/x86/lib/cmpxchg8b_emu.S
index 1c96be769adc..4bc06bd1aee1 100644
--- a/arch/x86/lib/cmpxchg8b_emu.S
+++ b/arch/x86/lib/cmpxchg8b_emu.S
@@ -7,7 +7,7 @@
 
 .text
 
-#ifndef CONFIG_X86_CMPXCHG64
+#ifndef CONFIG_X86_REQUIRED_FEATURE_CX8
 
 /*
  * Emulate 'cmpxchg8b (%esi)' on UP
diff --git a/lib/atomic64_test.c b/lib/atomic64_test.c
index d9d170238165..e68bde45b962 100644
--- a/lib/atomic64_test.c
+++ b/lib/atomic64_test.c
@@ -254,7 +254,7 @@ static __init int test_atomics_init(void)
 	pr_info("passed for %s platform %s CX8 and %s SSE\n",
 #ifdef CONFIG_X86_64
 		"x86-64",
-#elif defined(CONFIG_X86_CMPXCHG64)
+#elif defined(CONFIG_X86_REQUIRED_FEATURE_CX8)
 		"i586+",
 #else
 		"i386+",
diff --git a/tools/arch/x86/include/asm/required-features.h b/tools/arch/x86/include/asm/required-features.h
index e9187ddd3d1f..cef8104c103c 100644
--- a/tools/arch/x86/include/asm/required-features.h
+++ b/tools/arch/x86/include/asm/required-features.h
@@ -23,13 +23,13 @@
 # define NEED_PAE	0
 #endif
 
-#ifdef CONFIG_X86_CMPXCHG64
+#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
 # define NEED_CX8	(1<<(X86_FEATURE_CX8 & 31))
 #else
 # define NEED_CX8	0
 #endif
 
-#if defined(CONFIG_X86_CMOV) || defined(CONFIG_X86_64)
+#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
 # define NEED_CMOV	(1<<(X86_FEATURE_CMOV & 31))
 #else
 # define NEED_CMOV	0
-- 
2.45.2

[PATCH v3 2/4] x86/cpufeatures: Generate a feature mask header based on build config

[Xin Li (Intel)]

From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Introduce an AWK script to auto-generate a header with required and
disabled feature masks based on <asm/cpufeatures.h> and current build
config. Thus for any CPU feature with a build config, e.g., X86_FRED,
simply add

config X86_DISABLED_FEATURE_FRED
	def_bool y
	depends on !X86_FRED

to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
feature disable flag, e.g., DISABLE_FRED.

Lastly the generated required and disabled feature masks will be added
to their corresponding feature masks for this particular compile-time
configuration.

[ Xin: build integration improvements ]

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---

Changes since v2:
* Remove AWK code that generates extra debugging comments (Brian Gerst).
* Move SSE_MASK to verify_cpu.S, the only place it is used (Brian Gerst).

Change since v1:
* Remove code generating unused macros {REQUIRED,DISABLED}_FEATURE(x)
  to tell if a CPU feature, e.g., X86_FEATURE_FRED, is a required or
  disabled feature for this particular compile-time configuration.
---
 arch/x86/Makefile                  | 17 +++++-
 arch/x86/boot/cpucheck.c           |  3 +-
 arch/x86/boot/cpuflags.c           |  1 -
 arch/x86/boot/mkcpustr.c           |  3 +-
 arch/x86/include/asm/Kbuild        |  1 +
 arch/x86/include/asm/cpufeature.h  |  1 +
 arch/x86/include/asm/cpufeatures.h |  8 ---
 arch/x86/kernel/verify_cpu.S       |  4 ++
 arch/x86/tools/featuremasks.awk    | 84 ++++++++++++++++++++++++++++++
 9 files changed, 108 insertions(+), 14 deletions(-)
 create mode 100755 arch/x86/tools/featuremasks.awk

diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 801fd85c3ef6..211c0820b150 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -261,9 +261,22 @@ archscripts: scripts_basic
 	$(Q)$(MAKE) $(build)=arch/x86/tools relocs
 
 ###
-# Syscall table generation
+# Feature masks header and syscall table generation
 
-archheaders:
+out := arch/x86/include/generated/asm
+featuremasks_hdr := featuremasks.h
+featuremasks_awk := $(srctree)/arch/x86/tools/featuremasks.awk
+cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h
+quiet_cmd_gen_featuremasks = GEN     $@
+      cmd_gen_featuremasks = $(AWK) -f $(featuremasks_awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) > $@
+
+$(out)/$(featuremasks_hdr): $(featuremasks_awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE
+	$(shell mkdir -p $(out))
+	$(call if_changed,gen_featuremasks)
+
+targets += $(out)/$(featuremasks_hdr)
+
+archheaders: $(out)/$(featuremasks_hdr)
 	$(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all
 
 ###
diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c
index 0aae4d4ed615..8d03a741d1b2 100644
--- a/arch/x86/boot/cpucheck.c
+++ b/arch/x86/boot/cpucheck.c
@@ -22,10 +22,11 @@
 # include "boot.h"
 #endif
 #include <linux/types.h>
+#include <asm/featuremasks.h>
 #include <asm/intel-family.h>
 #include <asm/processor-flags.h>
-#include <asm/required-features.h>
 #include <asm/msr-index.h>
+
 #include "string.h"
 #include "msr.h"
 
diff --git a/arch/x86/boot/cpuflags.c b/arch/x86/boot/cpuflags.c
index d75237ba7ce9..0cabdacb2a2f 100644
--- a/arch/x86/boot/cpuflags.c
+++ b/arch/x86/boot/cpuflags.c
@@ -3,7 +3,6 @@
 #include "bitops.h"
 
 #include <asm/processor-flags.h>
-#include <asm/required-features.h>
 #include <asm/msr-index.h>
 #include "cpuflags.h"
 
diff --git a/arch/x86/boot/mkcpustr.c b/arch/x86/boot/mkcpustr.c
index da0ccc5de538..b90110109675 100644
--- a/arch/x86/boot/mkcpustr.c
+++ b/arch/x86/boot/mkcpustr.c
@@ -12,8 +12,6 @@
 
 #include <stdio.h>
 
-#include "../include/asm/required-features.h"
-#include "../include/asm/disabled-features.h"
 #include "../include/asm/cpufeatures.h"
 #include "../include/asm/vmxfeatures.h"
 #include "../kernel/cpu/capflags.c"
@@ -23,6 +21,7 @@ int main(void)
 	int i, j;
 	const char *str;
 
+	printf("#include <asm/featuremasks.h>\n\n");
 	printf("static const char x86_cap_strs[] =\n");
 
 	for (i = 0; i < NCAPINTS; i++) {
diff --git a/arch/x86/include/asm/Kbuild b/arch/x86/include/asm/Kbuild
index a192bdea69e2..29c3481f40fc 100644
--- a/arch/x86/include/asm/Kbuild
+++ b/arch/x86/include/asm/Kbuild
@@ -8,6 +8,7 @@ generated-y += syscalls_x32.h
 generated-y += unistd_32_ia32.h
 generated-y += unistd_64_x32.h
 generated-y += xen-hypercalls.h
+generated-y += featuremasks.h
 
 generic-y += early_ioremap.h
 generic-y += mcs_spinlock.h
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 0b9611da6c53..8332f596ba3c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -9,6 +9,7 @@
 #include <asm/asm.h>
 #include <linux/bitops.h>
 #include <asm/alternative.h>
+#include <asm/featuremasks.h>
 
 enum cpuid_leafs
 {
diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 6007462e03d6..4a297a8a376c 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -2,14 +2,6 @@
 #ifndef _ASM_X86_CPUFEATURES_H
 #define _ASM_X86_CPUFEATURES_H
 
-#ifndef _ASM_X86_REQUIRED_FEATURES_H
-#include <asm/required-features.h>
-#endif
-
-#ifndef _ASM_X86_DISABLED_FEATURES_H
-#include <asm/disabled-features.h>
-#endif
-
 /*
  * Defines x86 CPU feature bits
  */
diff --git a/arch/x86/kernel/verify_cpu.S b/arch/x86/kernel/verify_cpu.S
index 1258a5872d12..a23a65d5d177 100644
--- a/arch/x86/kernel/verify_cpu.S
+++ b/arch/x86/kernel/verify_cpu.S
@@ -29,8 +29,12 @@
  */
 
 #include <asm/cpufeatures.h>
+#include <asm/featuremasks.h>
 #include <asm/msr-index.h>
 
+#define SSE_MASK	\
+	(REQUIRED_MASK0 & ((1<<(X86_FEATURE_XMM & 31)) | (1<<(X86_FEATURE_XMM2 & 31))))
+
 SYM_FUNC_START_LOCAL(verify_cpu)
 	pushf				# Save caller passed flags
 	push	$0			# Kill any dangerous flags
diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
new file mode 100755
index 000000000000..989b021e73d3
--- /dev/null
+++ b/arch/x86/tools/featuremasks.awk
@@ -0,0 +1,84 @@
+#!/usr/bin/awk
+#
+# Convert cpufeatures.h to a list of compile-time masks
+# Note: this blithly assumes that each word has at least one
+# feature defined in it; if not, something else is wrong!
+#
+
+BEGIN {
+	printf "#ifndef _ASM_X86_FEATUREMASKS_H\n";
+	printf "#define _ASM_X86_FEATUREMASKS_H\n\n";
+
+	file = 0
+}
+
+BEGINFILE {
+	switch (++file) {
+	case 1:			# cpufeatures.h
+		FPAT = "#[ \t]*[a-z]+|[A-Za-z0-9_]+|[^ \t]";
+		break;
+	case 2:			# .config
+		FPAT = "CONFIG_[A-Z0-9_]+|is not set|[yn]";
+		break;
+	}
+}
+
+file == 1 && $1 ~ /^#[ \t]*define$/ && $2 ~ /^X86_FEATURE_/ &&
+$3 == "(" && $5 == "*" && $7 == "+" && $9 == ")" {
+	nfeat = $4 * $6 + $8;
+	feat = $2;
+	sub(/^X86_FEATURE_/, "", feat);
+	feats[nfeat] = feat;
+}
+file == 1 && $1 ~ /^#[ \t]*define$/ && $2 == "NCAPINTS" {
+	ncapints = strtonum($3);
+}
+
+file == 2 && $1 ~ /^CONFIG_X86_[A-Z]*_FEATURE_/ {
+	on = ($2 == "y");
+	if (split($1, fs, "CONFIG_X86_|_FEATURE_") == 3)
+		featstat[fs[2], fs[3]] = on;
+}
+
+END {
+	sets[1] = "REQUIRED";
+	sets[2] = "DISABLED";
+
+	for (ns in sets) {
+		s = sets[ns];
+
+		printf "/*\n";
+		printf " * %s features:\n", s;
+		printf " *\n";
+		fstr = "";
+		for (i = 0; i < ncapints; i++) {
+			mask = 0;
+			for (j = 0; j < 32; j++) {
+				nfeat = i*32 + j;
+				feat = feats[nfeat];
+				if (feat) {
+					st = !!featstat[s, feat];
+					if (st) {
+						nfstr = fstr " " feat;
+						if (length(nfstr) > 72) {
+							printf " *   %s\n", fstr;
+							nfstr = " " feat;
+						}
+						fstr = nfstr;
+					}
+					mask += st * (2 ^ j);
+				}
+			}
+			masks[i] = mask;
+		}
+		printf " *   %s\n */\n\n", fstr;
+
+		for (i = 0; i < ncapints; i++) {
+			printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
+		}
+
+		printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
+	}
+
+	printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
+}
-- 
2.45.2

[PATCH v3 3/4] x86/cpufeatures: Remove {disabled,required}-features.h

[Xin Li (Intel)]

The functionalities of {disabled,required}-features.h are replaced
with the auto-generated header cpufeature_masks.h. Thus they are no
longer needed. So delete them.

None of the macros defined in {disabled,required}-features.h is used
in tools, delete them too.

Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---
 arch/x86/include/asm/disabled-features.h      | 161 ------------------
 arch/x86/include/asm/required-features.h      | 105 ------------
 tools/arch/x86/include/asm/cpufeatures.h      |   8 -
 .../arch/x86/include/asm/disabled-features.h  | 161 ------------------
 .../arch/x86/include/asm/required-features.h  | 105 ------------
 tools/perf/check-headers.sh                   |   2 -
 6 files changed, 542 deletions(-)
 delete mode 100644 arch/x86/include/asm/disabled-features.h
 delete mode 100644 arch/x86/include/asm/required-features.h
 delete mode 100644 tools/arch/x86/include/asm/disabled-features.h
 delete mode 100644 tools/arch/x86/include/asm/required-features.h

diff --git a/arch/x86/include/asm/disabled-features.h b/arch/x86/include/asm/disabled-features.h
deleted file mode 100644
index c492bdc97b05..000000000000
--- a/arch/x86/include/asm/disabled-features.h
+++ /dev/null
@@ -1,161 +0,0 @@
-#ifndef _ASM_X86_DISABLED_FEATURES_H
-#define _ASM_X86_DISABLED_FEATURES_H
-
-/* These features, although they might be available in a CPU
- * will not be used because the compile options to support
- * them are not present.
- *
- * This code allows them to be checked and disabled at
- * compile time without an explicit #ifdef.  Use
- * cpu_feature_enabled().
- */
-
-#ifdef CONFIG_X86_UMIP
-# define DISABLE_UMIP	0
-#else
-# define DISABLE_UMIP	(1<<(X86_FEATURE_UMIP & 31))
-#endif
-
-#ifdef CONFIG_X86_64
-# define DISABLE_VME		(1<<(X86_FEATURE_VME & 31))
-# define DISABLE_K6_MTRR	(1<<(X86_FEATURE_K6_MTRR & 31))
-# define DISABLE_CYRIX_ARR	(1<<(X86_FEATURE_CYRIX_ARR & 31))
-# define DISABLE_CENTAUR_MCR	(1<<(X86_FEATURE_CENTAUR_MCR & 31))
-# define DISABLE_PCID		0
-#else
-# define DISABLE_VME		0
-# define DISABLE_K6_MTRR	0
-# define DISABLE_CYRIX_ARR	0
-# define DISABLE_CENTAUR_MCR	0
-# define DISABLE_PCID		(1<<(X86_FEATURE_PCID & 31))
-#endif /* CONFIG_X86_64 */
-
-#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-# define DISABLE_PKU		0
-# define DISABLE_OSPKE		0
-#else
-# define DISABLE_PKU		(1<<(X86_FEATURE_PKU & 31))
-# define DISABLE_OSPKE		(1<<(X86_FEATURE_OSPKE & 31))
-#endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
-
-#ifdef CONFIG_X86_5LEVEL
-# define DISABLE_LA57	0
-#else
-# define DISABLE_LA57	(1<<(X86_FEATURE_LA57 & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
-# define DISABLE_PTI		0
-#else
-# define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_RETPOLINE
-# define DISABLE_RETPOLINE	0
-#else
-# define DISABLE_RETPOLINE	((1 << (X86_FEATURE_RETPOLINE & 31)) | \
-				 (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
-#endif
-
-#ifdef CONFIG_MITIGATION_RETHUNK
-# define DISABLE_RETHUNK	0
-#else
-# define DISABLE_RETHUNK	(1 << (X86_FEATURE_RETHUNK & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_UNRET_ENTRY
-# define DISABLE_UNRET		0
-#else
-# define DISABLE_UNRET		(1 << (X86_FEATURE_UNRET & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_CALL_DEPTH_TRACKING
-# define DISABLE_CALL_DEPTH_TRACKING	0
-#else
-# define DISABLE_CALL_DEPTH_TRACKING	(1 << (X86_FEATURE_CALL_DEPTH & 31))
-#endif
-
-#ifdef CONFIG_ADDRESS_MASKING
-# define DISABLE_LAM		0
-#else
-# define DISABLE_LAM		(1 << (X86_FEATURE_LAM & 31))
-#endif
-
-#ifdef CONFIG_INTEL_IOMMU_SVM
-# define DISABLE_ENQCMD		0
-#else
-# define DISABLE_ENQCMD		(1 << (X86_FEATURE_ENQCMD & 31))
-#endif
-
-#ifdef CONFIG_X86_SGX
-# define DISABLE_SGX	0
-#else
-# define DISABLE_SGX	(1 << (X86_FEATURE_SGX & 31))
-#endif
-
-#ifdef CONFIG_XEN_PV
-# define DISABLE_XENPV		0
-#else
-# define DISABLE_XENPV		(1 << (X86_FEATURE_XENPV & 31))
-#endif
-
-#ifdef CONFIG_INTEL_TDX_GUEST
-# define DISABLE_TDX_GUEST	0
-#else
-# define DISABLE_TDX_GUEST	(1 << (X86_FEATURE_TDX_GUEST & 31))
-#endif
-
-#ifdef CONFIG_X86_USER_SHADOW_STACK
-#define DISABLE_USER_SHSTK	0
-#else
-#define DISABLE_USER_SHSTK	(1 << (X86_FEATURE_USER_SHSTK & 31))
-#endif
-
-#ifdef CONFIG_X86_KERNEL_IBT
-#define DISABLE_IBT	0
-#else
-#define DISABLE_IBT	(1 << (X86_FEATURE_IBT & 31))
-#endif
-
-#ifdef CONFIG_X86_FRED
-# define DISABLE_FRED	0
-#else
-# define DISABLE_FRED	(1 << (X86_FEATURE_FRED & 31))
-#endif
-
-#ifdef CONFIG_KVM_AMD_SEV
-#define DISABLE_SEV_SNP		0
-#else
-#define DISABLE_SEV_SNP		(1 << (X86_FEATURE_SEV_SNP & 31))
-#endif
-
-/*
- * Make sure to add features to the correct mask
- */
-#define DISABLED_MASK0	(DISABLE_VME)
-#define DISABLED_MASK1	0
-#define DISABLED_MASK2	0
-#define DISABLED_MASK3	(DISABLE_CYRIX_ARR|DISABLE_CENTAUR_MCR|DISABLE_K6_MTRR)
-#define DISABLED_MASK4	(DISABLE_PCID)
-#define DISABLED_MASK5	0
-#define DISABLED_MASK6	0
-#define DISABLED_MASK7	(DISABLE_PTI)
-#define DISABLED_MASK8	(DISABLE_XENPV|DISABLE_TDX_GUEST)
-#define DISABLED_MASK9	(DISABLE_SGX)
-#define DISABLED_MASK10	0
-#define DISABLED_MASK11	(DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
-			 DISABLE_CALL_DEPTH_TRACKING|DISABLE_USER_SHSTK)
-#define DISABLED_MASK12	(DISABLE_FRED|DISABLE_LAM)
-#define DISABLED_MASK13	0
-#define DISABLED_MASK14	0
-#define DISABLED_MASK15	0
-#define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
-			 DISABLE_ENQCMD)
-#define DISABLED_MASK17	0
-#define DISABLED_MASK18	(DISABLE_IBT)
-#define DISABLED_MASK19	(DISABLE_SEV_SNP)
-#define DISABLED_MASK20	0
-#define DISABLED_MASK21	0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 22)
-
-#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/arch/x86/include/asm/required-features.h b/arch/x86/include/asm/required-features.h
deleted file mode 100644
index cef8104c103c..000000000000
--- a/arch/x86/include/asm/required-features.h
+++ /dev/null
@@ -1,105 +0,0 @@
-#ifndef _ASM_X86_REQUIRED_FEATURES_H
-#define _ASM_X86_REQUIRED_FEATURES_H
-
-/* Define minimum CPUID feature set for kernel These bits are checked
-   really early to actually display a visible error message before the
-   kernel dies.  Make sure to assign features to the proper mask!
-
-   Some requirements that are not in CPUID yet are also in the
-   CONFIG_X86_MINIMUM_CPU_FAMILY which is checked too.
-
-   The real information is in arch/x86/Kconfig.cpu, this just converts
-   the CONFIGs into a bitmask */
-
-#ifndef CONFIG_MATH_EMULATION
-# define NEED_FPU	(1<<(X86_FEATURE_FPU & 31))
-#else
-# define NEED_FPU	0
-#endif
-
-#if defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
-# define NEED_PAE	(1<<(X86_FEATURE_PAE & 31))
-#else
-# define NEED_PAE	0
-#endif
-
-#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
-# define NEED_CX8	(1<<(X86_FEATURE_CX8 & 31))
-#else
-# define NEED_CX8	0
-#endif
-
-#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
-# define NEED_CMOV	(1<<(X86_FEATURE_CMOV & 31))
-#else
-# define NEED_CMOV	0
-#endif
-
-# define NEED_3DNOW	0
-
-#if defined(CONFIG_X86_P6_NOP) || defined(CONFIG_X86_64)
-# define NEED_NOPL	(1<<(X86_FEATURE_NOPL & 31))
-#else
-# define NEED_NOPL	0
-#endif
-
-#ifdef CONFIG_MATOM
-# define NEED_MOVBE	(1<<(X86_FEATURE_MOVBE & 31))
-#else
-# define NEED_MOVBE	0
-#endif
-
-#ifdef CONFIG_X86_64
-#ifdef CONFIG_PARAVIRT_XXL
-/* Paravirtualized systems may not have PSE or PGE available */
-#define NEED_PSE	0
-#define NEED_PGE	0
-#else
-#define NEED_PSE	(1<<(X86_FEATURE_PSE) & 31)
-#define NEED_PGE	(1<<(X86_FEATURE_PGE) & 31)
-#endif
-#define NEED_MSR	(1<<(X86_FEATURE_MSR & 31))
-#define NEED_FXSR	(1<<(X86_FEATURE_FXSR & 31))
-#define NEED_XMM	(1<<(X86_FEATURE_XMM & 31))
-#define NEED_XMM2	(1<<(X86_FEATURE_XMM2 & 31))
-#define NEED_LM		(1<<(X86_FEATURE_LM & 31))
-#else
-#define NEED_PSE	0
-#define NEED_MSR	0
-#define NEED_PGE	0
-#define NEED_FXSR	0
-#define NEED_XMM	0
-#define NEED_XMM2	0
-#define NEED_LM		0
-#endif
-
-#define REQUIRED_MASK0	(NEED_FPU|NEED_PSE|NEED_MSR|NEED_PAE|\
-			 NEED_CX8|NEED_PGE|NEED_FXSR|NEED_CMOV|\
-			 NEED_XMM|NEED_XMM2)
-#define SSE_MASK	(NEED_XMM|NEED_XMM2)
-
-#define REQUIRED_MASK1	(NEED_LM|NEED_3DNOW)
-
-#define REQUIRED_MASK2	0
-#define REQUIRED_MASK3	(NEED_NOPL)
-#define REQUIRED_MASK4	(NEED_MOVBE)
-#define REQUIRED_MASK5	0
-#define REQUIRED_MASK6	0
-#define REQUIRED_MASK7	0
-#define REQUIRED_MASK8	0
-#define REQUIRED_MASK9	0
-#define REQUIRED_MASK10	0
-#define REQUIRED_MASK11	0
-#define REQUIRED_MASK12	0
-#define REQUIRED_MASK13	0
-#define REQUIRED_MASK14	0
-#define REQUIRED_MASK15	0
-#define REQUIRED_MASK16	0
-#define REQUIRED_MASK17	0
-#define REQUIRED_MASK18	0
-#define REQUIRED_MASK19	0
-#define REQUIRED_MASK20	0
-#define REQUIRED_MASK21	0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 22)
-
-#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/tools/arch/x86/include/asm/cpufeatures.h b/tools/arch/x86/include/asm/cpufeatures.h
index 3c7434329661..05503448b94d 100644
--- a/tools/arch/x86/include/asm/cpufeatures.h
+++ b/tools/arch/x86/include/asm/cpufeatures.h
@@ -2,14 +2,6 @@
 #ifndef _ASM_X86_CPUFEATURES_H
 #define _ASM_X86_CPUFEATURES_H
 
-#ifndef _ASM_X86_REQUIRED_FEATURES_H
-#include <asm/required-features.h>
-#endif
-
-#ifndef _ASM_X86_DISABLED_FEATURES_H
-#include <asm/disabled-features.h>
-#endif
-
 /*
  * Defines x86 CPU feature bits
  */
diff --git a/tools/arch/x86/include/asm/disabled-features.h b/tools/arch/x86/include/asm/disabled-features.h
deleted file mode 100644
index c492bdc97b05..000000000000
--- a/tools/arch/x86/include/asm/disabled-features.h
+++ /dev/null
@@ -1,161 +0,0 @@
-#ifndef _ASM_X86_DISABLED_FEATURES_H
-#define _ASM_X86_DISABLED_FEATURES_H
-
-/* These features, although they might be available in a CPU
- * will not be used because the compile options to support
- * them are not present.
- *
- * This code allows them to be checked and disabled at
- * compile time without an explicit #ifdef.  Use
- * cpu_feature_enabled().
- */
-
-#ifdef CONFIG_X86_UMIP
-# define DISABLE_UMIP	0
-#else
-# define DISABLE_UMIP	(1<<(X86_FEATURE_UMIP & 31))
-#endif
-
-#ifdef CONFIG_X86_64
-# define DISABLE_VME		(1<<(X86_FEATURE_VME & 31))
-# define DISABLE_K6_MTRR	(1<<(X86_FEATURE_K6_MTRR & 31))
-# define DISABLE_CYRIX_ARR	(1<<(X86_FEATURE_CYRIX_ARR & 31))
-# define DISABLE_CENTAUR_MCR	(1<<(X86_FEATURE_CENTAUR_MCR & 31))
-# define DISABLE_PCID		0
-#else
-# define DISABLE_VME		0
-# define DISABLE_K6_MTRR	0
-# define DISABLE_CYRIX_ARR	0
-# define DISABLE_CENTAUR_MCR	0
-# define DISABLE_PCID		(1<<(X86_FEATURE_PCID & 31))
-#endif /* CONFIG_X86_64 */
-
-#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS
-# define DISABLE_PKU		0
-# define DISABLE_OSPKE		0
-#else
-# define DISABLE_PKU		(1<<(X86_FEATURE_PKU & 31))
-# define DISABLE_OSPKE		(1<<(X86_FEATURE_OSPKE & 31))
-#endif /* CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS */
-
-#ifdef CONFIG_X86_5LEVEL
-# define DISABLE_LA57	0
-#else
-# define DISABLE_LA57	(1<<(X86_FEATURE_LA57 & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_PAGE_TABLE_ISOLATION
-# define DISABLE_PTI		0
-#else
-# define DISABLE_PTI		(1 << (X86_FEATURE_PTI & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_RETPOLINE
-# define DISABLE_RETPOLINE	0
-#else
-# define DISABLE_RETPOLINE	((1 << (X86_FEATURE_RETPOLINE & 31)) | \
-				 (1 << (X86_FEATURE_RETPOLINE_LFENCE & 31)))
-#endif
-
-#ifdef CONFIG_MITIGATION_RETHUNK
-# define DISABLE_RETHUNK	0
-#else
-# define DISABLE_RETHUNK	(1 << (X86_FEATURE_RETHUNK & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_UNRET_ENTRY
-# define DISABLE_UNRET		0
-#else
-# define DISABLE_UNRET		(1 << (X86_FEATURE_UNRET & 31))
-#endif
-
-#ifdef CONFIG_MITIGATION_CALL_DEPTH_TRACKING
-# define DISABLE_CALL_DEPTH_TRACKING	0
-#else
-# define DISABLE_CALL_DEPTH_TRACKING	(1 << (X86_FEATURE_CALL_DEPTH & 31))
-#endif
-
-#ifdef CONFIG_ADDRESS_MASKING
-# define DISABLE_LAM		0
-#else
-# define DISABLE_LAM		(1 << (X86_FEATURE_LAM & 31))
-#endif
-
-#ifdef CONFIG_INTEL_IOMMU_SVM
-# define DISABLE_ENQCMD		0
-#else
-# define DISABLE_ENQCMD		(1 << (X86_FEATURE_ENQCMD & 31))
-#endif
-
-#ifdef CONFIG_X86_SGX
-# define DISABLE_SGX	0
-#else
-# define DISABLE_SGX	(1 << (X86_FEATURE_SGX & 31))
-#endif
-
-#ifdef CONFIG_XEN_PV
-# define DISABLE_XENPV		0
-#else
-# define DISABLE_XENPV		(1 << (X86_FEATURE_XENPV & 31))
-#endif
-
-#ifdef CONFIG_INTEL_TDX_GUEST
-# define DISABLE_TDX_GUEST	0
-#else
-# define DISABLE_TDX_GUEST	(1 << (X86_FEATURE_TDX_GUEST & 31))
-#endif
-
-#ifdef CONFIG_X86_USER_SHADOW_STACK
-#define DISABLE_USER_SHSTK	0
-#else
-#define DISABLE_USER_SHSTK	(1 << (X86_FEATURE_USER_SHSTK & 31))
-#endif
-
-#ifdef CONFIG_X86_KERNEL_IBT
-#define DISABLE_IBT	0
-#else
-#define DISABLE_IBT	(1 << (X86_FEATURE_IBT & 31))
-#endif
-
-#ifdef CONFIG_X86_FRED
-# define DISABLE_FRED	0
-#else
-# define DISABLE_FRED	(1 << (X86_FEATURE_FRED & 31))
-#endif
-
-#ifdef CONFIG_KVM_AMD_SEV
-#define DISABLE_SEV_SNP		0
-#else
-#define DISABLE_SEV_SNP		(1 << (X86_FEATURE_SEV_SNP & 31))
-#endif
-
-/*
- * Make sure to add features to the correct mask
- */
-#define DISABLED_MASK0	(DISABLE_VME)
-#define DISABLED_MASK1	0
-#define DISABLED_MASK2	0
-#define DISABLED_MASK3	(DISABLE_CYRIX_ARR|DISABLE_CENTAUR_MCR|DISABLE_K6_MTRR)
-#define DISABLED_MASK4	(DISABLE_PCID)
-#define DISABLED_MASK5	0
-#define DISABLED_MASK6	0
-#define DISABLED_MASK7	(DISABLE_PTI)
-#define DISABLED_MASK8	(DISABLE_XENPV|DISABLE_TDX_GUEST)
-#define DISABLED_MASK9	(DISABLE_SGX)
-#define DISABLED_MASK10	0
-#define DISABLED_MASK11	(DISABLE_RETPOLINE|DISABLE_RETHUNK|DISABLE_UNRET| \
-			 DISABLE_CALL_DEPTH_TRACKING|DISABLE_USER_SHSTK)
-#define DISABLED_MASK12	(DISABLE_FRED|DISABLE_LAM)
-#define DISABLED_MASK13	0
-#define DISABLED_MASK14	0
-#define DISABLED_MASK15	0
-#define DISABLED_MASK16	(DISABLE_PKU|DISABLE_OSPKE|DISABLE_LA57|DISABLE_UMIP| \
-			 DISABLE_ENQCMD)
-#define DISABLED_MASK17	0
-#define DISABLED_MASK18	(DISABLE_IBT)
-#define DISABLED_MASK19	(DISABLE_SEV_SNP)
-#define DISABLED_MASK20	0
-#define DISABLED_MASK21	0
-#define DISABLED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 22)
-
-#endif /* _ASM_X86_DISABLED_FEATURES_H */
diff --git a/tools/arch/x86/include/asm/required-features.h b/tools/arch/x86/include/asm/required-features.h
deleted file mode 100644
index cef8104c103c..000000000000
--- a/tools/arch/x86/include/asm/required-features.h
+++ /dev/null
@@ -1,105 +0,0 @@
-#ifndef _ASM_X86_REQUIRED_FEATURES_H
-#define _ASM_X86_REQUIRED_FEATURES_H
-
-/* Define minimum CPUID feature set for kernel These bits are checked
-   really early to actually display a visible error message before the
-   kernel dies.  Make sure to assign features to the proper mask!
-
-   Some requirements that are not in CPUID yet are also in the
-   CONFIG_X86_MINIMUM_CPU_FAMILY which is checked too.
-
-   The real information is in arch/x86/Kconfig.cpu, this just converts
-   the CONFIGs into a bitmask */
-
-#ifndef CONFIG_MATH_EMULATION
-# define NEED_FPU	(1<<(X86_FEATURE_FPU & 31))
-#else
-# define NEED_FPU	0
-#endif
-
-#if defined(CONFIG_X86_PAE) || defined(CONFIG_X86_64)
-# define NEED_PAE	(1<<(X86_FEATURE_PAE & 31))
-#else
-# define NEED_PAE	0
-#endif
-
-#ifdef CONFIG_X86_REQUIRED_FEATURE_CX8
-# define NEED_CX8	(1<<(X86_FEATURE_CX8 & 31))
-#else
-# define NEED_CX8	0
-#endif
-
-#if defined(CONFIG_X86_REQUIRED_FEATURE_CMOV) || defined(CONFIG_X86_64)
-# define NEED_CMOV	(1<<(X86_FEATURE_CMOV & 31))
-#else
-# define NEED_CMOV	0
-#endif
-
-# define NEED_3DNOW	0
-
-#if defined(CONFIG_X86_P6_NOP) || defined(CONFIG_X86_64)
-# define NEED_NOPL	(1<<(X86_FEATURE_NOPL & 31))
-#else
-# define NEED_NOPL	0
-#endif
-
-#ifdef CONFIG_MATOM
-# define NEED_MOVBE	(1<<(X86_FEATURE_MOVBE & 31))
-#else
-# define NEED_MOVBE	0
-#endif
-
-#ifdef CONFIG_X86_64
-#ifdef CONFIG_PARAVIRT_XXL
-/* Paravirtualized systems may not have PSE or PGE available */
-#define NEED_PSE	0
-#define NEED_PGE	0
-#else
-#define NEED_PSE	(1<<(X86_FEATURE_PSE) & 31)
-#define NEED_PGE	(1<<(X86_FEATURE_PGE) & 31)
-#endif
-#define NEED_MSR	(1<<(X86_FEATURE_MSR & 31))
-#define NEED_FXSR	(1<<(X86_FEATURE_FXSR & 31))
-#define NEED_XMM	(1<<(X86_FEATURE_XMM & 31))
-#define NEED_XMM2	(1<<(X86_FEATURE_XMM2 & 31))
-#define NEED_LM		(1<<(X86_FEATURE_LM & 31))
-#else
-#define NEED_PSE	0
-#define NEED_MSR	0
-#define NEED_PGE	0
-#define NEED_FXSR	0
-#define NEED_XMM	0
-#define NEED_XMM2	0
-#define NEED_LM		0
-#endif
-
-#define REQUIRED_MASK0	(NEED_FPU|NEED_PSE|NEED_MSR|NEED_PAE|\
-			 NEED_CX8|NEED_PGE|NEED_FXSR|NEED_CMOV|\
-			 NEED_XMM|NEED_XMM2)
-#define SSE_MASK	(NEED_XMM|NEED_XMM2)
-
-#define REQUIRED_MASK1	(NEED_LM|NEED_3DNOW)
-
-#define REQUIRED_MASK2	0
-#define REQUIRED_MASK3	(NEED_NOPL)
-#define REQUIRED_MASK4	(NEED_MOVBE)
-#define REQUIRED_MASK5	0
-#define REQUIRED_MASK6	0
-#define REQUIRED_MASK7	0
-#define REQUIRED_MASK8	0
-#define REQUIRED_MASK9	0
-#define REQUIRED_MASK10	0
-#define REQUIRED_MASK11	0
-#define REQUIRED_MASK12	0
-#define REQUIRED_MASK13	0
-#define REQUIRED_MASK14	0
-#define REQUIRED_MASK15	0
-#define REQUIRED_MASK16	0
-#define REQUIRED_MASK17	0
-#define REQUIRED_MASK18	0
-#define REQUIRED_MASK19	0
-#define REQUIRED_MASK20	0
-#define REQUIRED_MASK21	0
-#define REQUIRED_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 22)
-
-#endif /* _ASM_X86_REQUIRED_FEATURES_H */
diff --git a/tools/perf/check-headers.sh b/tools/perf/check-headers.sh
index 672421b858ac..3ef2fd511bc1 100755
--- a/tools/perf/check-headers.sh
+++ b/tools/perf/check-headers.sh
@@ -25,8 +25,6 @@ FILES=(
   "include/linux/hash.h"
   "include/linux/list-sort.h"
   "include/uapi/linux/hw_breakpoint.h"
-  "arch/x86/include/asm/disabled-features.h"
-  "arch/x86/include/asm/required-features.h"
   "arch/x86/include/asm/cpufeatures.h"
   "arch/x86/include/asm/inat_types.h"
   "arch/x86/include/asm/emulate_prefix.h"
-- 
2.45.2

[PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li (Intel)]

Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
script that generates the required and disabled feature mask header.

Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---
 arch/x86/include/asm/cpufeature.h | 69 -------------------------------
 arch/x86/tools/featuremasks.awk   | 12 +++++-
 2 files changed, 11 insertions(+), 70 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 8332f596ba3c..8161dfb3255c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -55,75 +55,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 #define test_cpu_cap(c, bit)						\
 	 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
 
-/*
- * There are 32 bits/features in each mask word.  The high bits
- * (selected with (bit>>5) give us the word number and the low 5
- * bits give us the bit/feature number inside the word.
- * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
- * see if it is set in the mask word.
- */
-#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)	\
-	(((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
-
-/*
- * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
- * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
- * header macros which use NCAPINTS need to be changed. The duplicated macro
- * use causes the compiler to issue errors for all headers so that all usage
- * sites can be corrected.
- */
-#define REQUIRED_MASK_BIT_SET(feature_bit)		\
-	 ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||	\
-	   REQUIRED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
-#define DISABLED_MASK_BIT_SET(feature_bit)				\
-	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||	\
-	   DISABLED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
 	 test_cpu_cap(c, bit))
diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
index 989b021e73d3..f6fe979a8fae 100755
--- a/arch/x86/tools/featuremasks.awk
+++ b/arch/x86/tools/featuremasks.awk
@@ -77,7 +77,17 @@ END {
 			printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
 		}
 
-		printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
+		printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
+		printf "\t((\t\t\t\t\t";
+		for (i = 0; i < ncapints; i++) {
+			if (masks[i])
+				printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
+		}
+		printf " 0\t\\\n";
+		printf "\t) & (1 << ((x) & 31)))\n";
+
+		printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
+		printf "\t(%s_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != %d))\n\n", s, ncapints;
 	}
 
 	printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
-- 
2.45.2

Re: [PATCH v3 0/4] x86/cpufeatures: Automatically generate required and disabled feature masks

[Xin Li]

On 6/22/2024 10:14 AM, Xin Li (Intel) wrote:
> The x86 build process first generates required and disabled feature
> masks based on current build config, and then uses these generated
> masks to compile the source code. When a CPU feature is not enabled
> in a build config, e.g., when CONFIG_X86_FRED=n, its feature disable
> flag, i.e., DISABLE_FRED, needs to be properly defined and added to
> a specific disabled CPU features mask in <asm/disabled-features.h>,
> as the following patch does:
> https://lore.kernel.org/all/20231205105030.8698-8-xin3.li@intel.com/.
> As a result, the FRED feature bit is surely cleared in the generated
> kernel binary when CONFIG_X86_FRED=n.
> 
> Recently there is another case to repeat the same exercise for the
> AMD SEV-SNP CPU feature:
> https://lore.kernel.org/all/20240126041126.1927228-2-michael.roth@amd.com/.
> https://lore.kernel.org/all/20240126041126.1927228-23-michael.roth@amd.com/.
> 
> It was one thing when there were four of CPU feature masks, but with
> over 20 it is going to cause mistakes, e.g.,
> https://lore.kernel.org/lkml/aaed79d5-d683-d1bc-7ba1-b33c8d6db618@suse.com/.
> 
> We want to eliminate the stupidly repeated exercise to manually assign
> features to CPU feature words through introducing an AWK script to
> automatically generate a header with required and disabled CPU feature
> masks based on current build config, and this patch set does that.
> 

Here is an example of the auto generated feature masks header:

ifndef _ASM_X86_FEATUREMASKS_H
#define _ASM_X86_FEATUREMASKS_H

/*
  * REQUIRED features:
  *
  *    FPU PSE MSR PAE CX8 PGE CMOV FXSR XMM XMM2 LM NOPL ALWAYS CPUID
  */

#define REQUIRED_MASK0  0x0700a169
#define REQUIRED_MASK1  0x20000000
#define REQUIRED_MASK2  0x00000000
#define REQUIRED_MASK3  0x02300000
#define REQUIRED_MASK4  0x00000000
#define REQUIRED_MASK5  0x00000000
#define REQUIRED_MASK6  0x00000000
#define REQUIRED_MASK7  0x00000000
#define REQUIRED_MASK8  0x00000000
#define REQUIRED_MASK9  0x00000000
#define REQUIRED_MASK10 0x00000000
#define REQUIRED_MASK11 0x00000000
#define REQUIRED_MASK12 0x00000000
#define REQUIRED_MASK13 0x00000000
#define REQUIRED_MASK14 0x00000000
#define REQUIRED_MASK15 0x00000000
#define REQUIRED_MASK16 0x00000000
#define REQUIRED_MASK17 0x00000000
#define REQUIRED_MASK18 0x00000000
#define REQUIRED_MASK19 0x00000000
#define REQUIRED_MASK20 0x00000000
#define REQUIRED_MASK21 0x00000000

#define REQUIRED_FEATURE(x)                             \
         ((                                              \
                 ((x) >> 5) ==  0 ? REQUIRED_MASK0 :     \
                 ((x) >> 5) ==  1 ? REQUIRED_MASK1 :     \
                 ((x) >> 5) ==  3 ? REQUIRED_MASK3 : 0   \
         ) & (1 << ((x) & 31)))

#define REQUIRED_MASK_BIT_SET(x)                        \
         (REQUIRED_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != 22))

/*
  * DISABLED features:
  *
  *    VME K6_MTRR CYRIX_ARR CENTAUR_MCR XENPV TDX_GUEST UNRET LAM SEV_SNP
  */

#define DISABLED_MASK0  0x00000002
#define DISABLED_MASK1  0x00000000
#define DISABLED_MASK2  0x00000000
#define DISABLED_MASK3  0x0000000e
#define DISABLED_MASK4  0x00000000
#define DISABLED_MASK5  0x00000000
#define DISABLED_MASK6  0x00000000
#define DISABLED_MASK7  0x00000000
#define DISABLED_MASK8  0x00410000
#define DISABLED_MASK9  0x00000000
#define DISABLED_MASK10 0x00000000
#define DISABLED_MASK11 0x00008000
#define DISABLED_MASK12 0x04000000
#define DISABLED_MASK13 0x00000000
#define DISABLED_MASK14 0x00000000
#define DISABLED_MASK15 0x00000000
#define DISABLED_MASK16 0x00000000
#define DISABLED_MASK17 0x00000000
#define DISABLED_MASK18 0x00000000
#define DISABLED_MASK19 0x00000010
#define DISABLED_MASK20 0x00000000
#define DISABLED_MASK21 0x00000000

#define DISABLED_FEATURE(x)                             \
         ((                                              \
                 ((x) >> 5) ==  0 ? DISABLED_MASK0 :     \
                 ((x) >> 5) ==  3 ? DISABLED_MASK3 :     \
                 ((x) >> 5) ==  8 ? DISABLED_MASK8 :     \
                 ((x) >> 5) == 11 ? DISABLED_MASK11 :    \
                 ((x) >> 5) == 12 ? DISABLED_MASK12 :    \
                 ((x) >> 5) == 19 ? DISABLED_MASK19 : 0  \
         ) & (1 << ((x) & 31)))

#define DISABLED_MASK_BIT_SET(x)                        \
         (DISABLED_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != 22))

#endif /* _ASM_X86_FEATUREMASKS_H */

Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Brian Gerst]

On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@zytor.com> wrote:
>
> Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
> script that generates the required and disabled feature mask header.
>
> Suggested-by: Brian Gerst <brgerst@gmail.com>
> Signed-off-by: Xin Li (Intel) <xin@zytor.com>
> ---
>  arch/x86/include/asm/cpufeature.h | 69 -------------------------------
>  arch/x86/tools/featuremasks.awk   | 12 +++++-
>  2 files changed, 11 insertions(+), 70 deletions(-)
>
> diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> index 8332f596ba3c..8161dfb3255c 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -55,75 +55,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
>  #define test_cpu_cap(c, bit)                                           \
>          arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
>
> -/*
> - * There are 32 bits/features in each mask word.  The high bits
> - * (selected with (bit>>5) give us the word number and the low 5
> - * bits give us the bit/feature number inside the word.
> - * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
> - * see if it is set in the mask word.
> - */
> -#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)    \
> -       (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
> -
> -/*
> - * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
> - * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
> - * header macros which use NCAPINTS need to be changed. The duplicated macro
> - * use causes the compiler to issue errors for all headers so that all usage
> - * sites can be corrected.
> - */
> -#define REQUIRED_MASK_BIT_SET(feature_bit)             \
> -        ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||    \
> -          REQUIRED_MASK_CHECK                                    ||    \
> -          BUILD_BUG_ON_ZERO(NCAPINTS != 22))
> -
> -#define DISABLED_MASK_BIT_SET(feature_bit)                             \
> -        ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||    \
> -          DISABLED_MASK_CHECK                                    ||    \
> -          BUILD_BUG_ON_ZERO(NCAPINTS != 22))
> -
>  #define cpu_has(c, bit)                                                        \
>         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
>          test_cpu_cap(c, bit))
> diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
> index 989b021e73d3..f6fe979a8fae 100755
> --- a/arch/x86/tools/featuremasks.awk
> +++ b/arch/x86/tools/featuremasks.awk
> @@ -77,7 +77,17 @@ END {
>                         printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
>                 }
>
> -               printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
> +               printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
> +               printf "\t((\t\t\t\t\t";
> +               for (i = 0; i < ncapints; i++) {
> +                       if (masks[i])
> +                               printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
> +               }
> +               printf " 0\t\\\n";
> +               printf "\t) & (1 << ((x) & 31)))\n";

The original macro had 1UL here.  I don't know if it is strictly
necessary in this case since we're using 32-bit masks, but it would
probably be safer.

> +
> +               printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
> +               printf "\t(%s_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != %d))\n\n", s, ncapints;

Checking NCAPINTS isn't necessary anymore.  It was needed when these
macros had to be manually updated, but now if cpufeatures.h changes
this header will be regenerated.

>         }
>
>         printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
> --
> 2.45.2
>

Otherwise, it looks good.


Brian Gerst

Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li]

On 6/23/2024 1:28 PM, Brian Gerst wrote:
> On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@zytor.com> wrote:
>>
>> Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
>> script that generates the required and disabled feature mask header.
>>
>> Suggested-by: Brian Gerst <brgerst@gmail.com>
>> Signed-off-by: Xin Li (Intel) <xin@zytor.com>
>> ---
>>   arch/x86/include/asm/cpufeature.h | 69 -------------------------------
>>   arch/x86/tools/featuremasks.awk   | 12 +++++-
>>   2 files changed, 11 insertions(+), 70 deletions(-)
>>

>> -               printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
>> +               printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
>> +               printf "\t((\t\t\t\t\t";
>> +               for (i = 0; i < ncapints; i++) {
>> +                       if (masks[i])
>> +                               printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
>> +               }
>> +               printf " 0\t\\\n";
>> +               printf "\t) & (1 << ((x) & 31)))\n";
> 
> The original macro had 1UL here.  I don't know if it is strictly
> necessary in this case since we're using 32-bit masks, but it would
> probably be safer.

I did notice it, but don't think UL is needed.

>> +
>> +               printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
>> +               printf "\t(%s_FEATURE(x) || BUILD_BUG_ON_ZERO(NCAPINTS != %d))\n\n", s, ncapints;
> 
> Checking NCAPINTS isn't necessary anymore.  It was needed when these
> macros had to be manually updated, but now if cpufeatures.h changes
> this header will be regenerated.

Right, it's no longer needed.  Let me update this patch.

Thanks!
     Xin

[PATCH v3A 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li (Intel)]

Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
script that generates the required and disabled feature mask header.

Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---

Change since v3:
* Checking NCAPINTS isn't necessary anymore.  It was needed when these
  macros had to be manually updated, but now if cpufeatures.h changes
  this header will be regenerated (Brian Gerst).
---
 arch/x86/include/asm/cpufeature.h | 69 -------------------------------
 arch/x86/tools/featuremasks.awk   |  9 +++-
 2 files changed, 8 insertions(+), 70 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 8332f596ba3c..8161dfb3255c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -55,75 +55,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 #define test_cpu_cap(c, bit)						\
 	 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
 
-/*
- * There are 32 bits/features in each mask word.  The high bits
- * (selected with (bit>>5) give us the word number and the low 5
- * bits give us the bit/feature number inside the word.
- * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
- * see if it is set in the mask word.
- */
-#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)	\
-	(((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
-
-/*
- * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
- * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
- * header macros which use NCAPINTS need to be changed. The duplicated macro
- * use causes the compiler to issue errors for all headers so that all usage
- * sites can be corrected.
- */
-#define REQUIRED_MASK_BIT_SET(feature_bit)		\
-	 ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||	\
-	   REQUIRED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
-#define DISABLED_MASK_BIT_SET(feature_bit)				\
-	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||	\
-	   DISABLED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
 	 test_cpu_cap(c, bit))
diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
index 989b021e73d3..2a936411c219 100755
--- a/arch/x86/tools/featuremasks.awk
+++ b/arch/x86/tools/featuremasks.awk
@@ -77,7 +77,14 @@ END {
 			printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
 		}
 
-		printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
+		printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
+		printf "\t((\t\t\t\t\t";
+		for (i = 0; i < ncapints; i++) {
+			if (masks[i])
+				printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
+		}
+		printf " 0\t\\\n";
+		printf "\t) & (1 << ((x) & 31)))\n";
 	}
 
 	printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
-- 
2.45.2

Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Andrew Cooper]

On 24/06/2024 8:29 am, Xin Li wrote:
> On 6/23/2024 1:28 PM, Brian Gerst wrote:
>> On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@zytor.com> wrote:
>>> -               printf "#define %s_MASK_CHECK
>>> BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
>>> +               printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
>>> +               printf "\t((\t\t\t\t\t";
>>> +               for (i = 0; i < ncapints; i++) {
>>> +                       if (masks[i])
>>> +                               printf "\t\\\n\t\t((x) >> 5) == %2d
>>> ? %s_MASK%d :", i, s, i;
>>> +               }
>>> +               printf " 0\t\\\n";
>>> +               printf "\t) & (1 << ((x) & 31)))\n";
>>
>> The original macro had 1UL here.  I don't know if it is strictly
>> necessary in this case since we're using 32-bit masks, but it would
>> probably be safer.
>
> I did notice it, but don't think UL is needed.

You do need 1U, or you'll trip UBSAN every time you test feature 31 in a
word.

I'll note that the hypervisor bit is one such example.

~Andrew

Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li]

On 6/24/2024 3:24 AM, Andrew Cooper wrote:
> On 24/06/2024 8:29 am, Xin Li wrote:
>> On 6/23/2024 1:28 PM, Brian Gerst wrote:
>>> On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@zytor.com> wrote:
>>>> -               printf "#define %s_MASK_CHECK
>>>> BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
>>>> +               printf "\n#define %s_FEATURE(x)\t\t\t\t\\\n", s;
>>>> +               printf "\t((\t\t\t\t\t";
>>>> +               for (i = 0; i < ncapints; i++) {
>>>> +                       if (masks[i])
>>>> +                               printf "\t\\\n\t\t((x) >> 5) == %2d
>>>> ? %s_MASK%d :", i, s, i;
>>>> +               }
>>>> +               printf " 0\t\\\n";
>>>> +               printf "\t) & (1 << ((x) & 31)))\n";
>>>
>>> The original macro had 1UL here.  I don't know if it is strictly
>>> necessary in this case since we're using 32-bit masks, but it would
>>> probably be safer.
>>
>> I did notice it, but don't think UL is needed.
> 
> You do need 1U, or you'll trip UBSAN every time you test feature 31 in a
> word.

This is so obvious, how come I totally missed it!

> I'll note that the hypervisor bit is one such example.

What's more, generally bit 31 is nothing special, I find:
#define X86_FEATURE_PBE		( 0*32+31) /* Pending Break Enable */
#define X86_FEATURE_3DNOW	( 1*32+31) /* 3DNow */
#define X86_FEATURE_TSC_KNOWN_FREQ	( 3*32+31) /* TSC has known frequency */
...

Definitely I must append "U".

Thanks!
     Xin

[PATCH v3B 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li (Intel)]

Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
script that generates the required and disabled feature mask header.

Suggested-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
---

Change since v3A:
* Use '1U' instead of '1' in feature mask shifting (Andrew Cooper).

Change since v3:
* Checking NCAPINTS isn't necessary anymore.  It was needed when these
  macros had to be manually updated, but now if cpufeatures.h changes
  this header will be regenerated (Brian Gerst).
---
 arch/x86/include/asm/cpufeature.h | 69 -------------------------------
 arch/x86/tools/featuremasks.awk   |  9 +++-
 2 files changed, 8 insertions(+), 70 deletions(-)

diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index 8332f596ba3c..8161dfb3255c 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -55,75 +55,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
 #define test_cpu_cap(c, bit)						\
 	 arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
 
-/*
- * There are 32 bits/features in each mask word.  The high bits
- * (selected with (bit>>5) give us the word number and the low 5
- * bits give us the bit/feature number inside the word.
- * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
- * see if it is set in the mask word.
- */
-#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)	\
-	(((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
-
-/*
- * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
- * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
- * header macros which use NCAPINTS need to be changed. The duplicated macro
- * use causes the compiler to issue errors for all headers so that all usage
- * sites can be corrected.
- */
-#define REQUIRED_MASK_BIT_SET(feature_bit)		\
-	 ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||	\
-	   REQUIRED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
-#define DISABLED_MASK_BIT_SET(feature_bit)				\
-	 ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||	\
-	   CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||	\
-	   DISABLED_MASK_CHECK					  ||	\
-	   BUILD_BUG_ON_ZERO(NCAPINTS != 22))
-
 #define cpu_has(c, bit)							\
 	(__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :	\
 	 test_cpu_cap(c, bit))
diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
index 989b021e73d3..e0383683e630 100755
--- a/arch/x86/tools/featuremasks.awk
+++ b/arch/x86/tools/featuremasks.awk
@@ -77,7 +77,14 @@ END {
 			printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
 		}
 
-		printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
+		printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
+		printf "\t((\t\t\t\t\t";
+		for (i = 0; i < ncapints; i++) {
+			if (masks[i])
+				printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
+		}
+		printf " 0\t\\\n";
+		printf "\t) & (1U << ((x) & 31)))\n";
 	}
 
 	printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
-- 
2.45.2

Re: [PATCH v3 2/4] x86/cpufeatures: Generate a feature mask header based on build config

[Nikolay Borisov]

On 22.06.24 г. 20:14 ч., Xin Li (Intel) wrote:
> From: "H. Peter Anvin (Intel)" <hpa@zytor.com>
> 
> Introduce an AWK script to auto-generate a header with required and
> disabled feature masks based on <asm/cpufeatures.h> and current build
> config. Thus for any CPU feature with a build config, e.g., X86_FRED,
> simply add
> 
> config X86_DISABLED_FEATURE_FRED
> 	def_bool y
> 	depends on !X86_FRED
> 
> to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
> feature disable flag, e.g., DISABLE_FRED.
> 
> Lastly the generated required and disabled feature masks will be added
> to their corresponding feature masks for this particular compile-time
> configuration.
> 
> [ Xin: build integration improvements ]
> 
> Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
> Signed-off-by: Xin Li (Intel) <xin@zytor.com>

Overall LGTM, some minor points below.


Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>


<snip>

> diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
> new file mode 100755
> index 000000000000..989b021e73d3
> --- /dev/null
> +++ b/arch/x86/tools/featuremasks.awk
> @@ -0,0 +1,84 @@
> +#!/usr/bin/awk
> +#
> +# Convert cpufeatures.h to a list of compile-time masks
> +# Note: this blithly assumes that each word has at least one
> +# feature defined in it; if not, something else is wrong!
> +#
> +
> +BEGIN {
> +	printf "#ifndef _ASM_X86_FEATUREMASKS_H\n";
> +	printf "#define _ASM_X86_FEATUREMASKS_H\n\n";
> +
> +	file = 0
> +}
> +
> +BEGINFILE {
> +	switch (++file) {
> +	case 1:			# cpufeatures.h
> +		FPAT = "#[ \t]*[a-z]+|[A-Za-z0-9_]+|[^ \t]";
> +		break;
> +	case 2:			# .config
> +		FPAT = "CONFIG_[A-Z0-9_]+|is not set|[yn]";
> +		break;
> +	}
> +}
> +

IMO this script could use a bit of high-level comments. Something like:


# Create a dictionary of sorts, containing all defined feature bits
> +file == 1 && $1 ~ /^#[ \t]*define$/ && $2 ~ /^X86_FEATURE_/ &&
> +$3 == "(" && $5 == "*" && $7 == "+" && $9 == ")" {
> +	nfeat = $4 * $6 + $8;
> +	feat = $2;
> +	sub(/^X86_FEATURE_/, "", feat);
> +	feats[nfeat] = feat;
> +}

> +file == 1 && $1 ~ /^#[ \t]*define$/ && $2 == "NCAPINTS" {
> +	ncapints = strtonum($3);
> +}
> +

# Create a dictionary featstat[REQUIRED|DISABLED, FEATURE_NAME] = on | off

> +file == 2 && $1 ~ /^CONFIG_X86_[A-Z]*_FEATURE_/ {
> +	on = ($2 == "y");
> +	if (split($1, fs, "CONFIG_X86_|_FEATURE_") == 3)
> +		featstat[fs[2], fs[3]] = on;
> +}
> +
> +END {
> +	sets[1] = "REQUIRED";
> +	sets[2] = "DISABLED";
> +
> +	for (ns in sets) {
> +		s = sets[ns];
> +
> +		printf "/*\n";
> +		printf " * %s features:\n", s;
> +		printf " *\n";
> +		fstr = "";
> +		for (i = 0; i < ncapints; i++) {
> +			mask = 0;
> +			for (j = 0; j < 32; j++) {
> +				nfeat = i*32 + j;
> +				feat = feats[nfeat];
> +				if (feat) {
> +					st = !!featstat[s, feat];
> +					if (st) {
> +						nfstr = fstr " " feat;
> +						if (length(nfstr) > 72) {
> +							printf " *   %s\n", fstr;
> +							nfstr = " " feat;
> +						}
> +						fstr = nfstr;
> +					}
> +					mask += st * (2 ^ j);

nit: This expression can be changed to mask += (2 ^j) and moved inside 
the 'if (st)' branch. Essentially only add a bit iff that status of the 
relevant feature in the kconfig is y, which is signified by the value of 
'st' variable.

> +				}
> +			}
> +			masks[i] = mask;
> +		}
> +		printf " *   %s\n */\n\n", fstr;
> +
> +		for (i = 0; i < ncapints; i++) {
> +			printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
> +		}
> +
> +		printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
> +	}
> +
> +	printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
> +}

Re: [PATCH v3 2/4] x86/cpufeatures: Generate a feature mask header based on build config

[Xin Li]

On 6/26/2024 4:36 AM, Nikolay Borisov wrote:
> 
> 
> On 22.06.24 г. 20:14 ч., Xin Li (Intel) wrote:
>> From: "H. Peter Anvin (Intel)" <hpa@zytor.com>
>>
>> Introduce an AWK script to auto-generate a header with required and
>> disabled feature masks based on <asm/cpufeatures.h> and current build
>> config. Thus for any CPU feature with a build config, e.g., X86_FRED,
>> simply add
>>
>> config X86_DISABLED_FEATURE_FRED
>>     def_bool y
>>     depends on !X86_FRED
>>
>> to arch/x86/Kconfig.cpufeatures, instead of adding a conditional CPU
>> feature disable flag, e.g., DISABLE_FRED.
>>
>> Lastly the generated required and disabled feature masks will be added
>> to their corresponding feature masks for this particular compile-time
>> configuration.
>>
>> [ Xin: build integration improvements ]
>>
>> Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
>> Signed-off-by: Xin Li (Intel) <xin@zytor.com>
> 
> Overall LGTM, some minor points below.
> 
> 
> Reviewed-by: Nikolay Borisov <nik.borisov@suse.com>

Thanks!

> 
> 
> <snip>
> 
>> diff --git a/arch/x86/tools/featuremasks.awk 
>> b/arch/x86/tools/featuremasks.awk
>> new file mode 100755
>> index 000000000000..989b021e73d3
>> --- /dev/null
>> +++ b/arch/x86/tools/featuremasks.awk
>> @@ -0,0 +1,84 @@
>> +#!/usr/bin/awk
>> +#
>> +# Convert cpufeatures.h to a list of compile-time masks
>> +# Note: this blithly assumes that each word has at least one
>> +# feature defined in it; if not, something else is wrong!
>> +#
>> +
>> +BEGIN {
>> +    printf "#ifndef _ASM_X86_FEATUREMASKS_H\n";
>> +    printf "#define _ASM_X86_FEATUREMASKS_H\n\n";
>> +
>> +    file = 0
>> +}
>> +
>> +BEGINFILE {
>> +    switch (++file) {
>> +    case 1:            # cpufeatures.h
>> +        FPAT = "#[ \t]*[a-z]+|[A-Za-z0-9_]+|[^ \t]";
>> +        break;
>> +    case 2:            # .config
>> +        FPAT = "CONFIG_[A-Z0-9_]+|is not set|[yn]";
>> +        break;
>> +    }
>> +}
>> +
> 
> IMO this script could use a bit of high-level comments. Something like:
> 
> 
> # Create a dictionary of sorts, containing all defined feature bits
>> +file == 1 && $1 ~ /^#[ \t]*define$/ && $2 ~ /^X86_FEATURE_/ &&
>> +$3 == "(" && $5 == "*" && $7 == "+" && $9 == ")" {
>> +    nfeat = $4 * $6 + $8;
>> +    feat = $2;
>> +    sub(/^X86_FEATURE_/, "", feat);
>> +    feats[nfeat] = feat;
>> +}
> 
>> +file == 1 && $1 ~ /^#[ \t]*define$/ && $2 == "NCAPINTS" {
>> +    ncapints = strtonum($3);
>> +}
>> +
> 
> # Create a dictionary featstat[REQUIRED|DISABLED, FEATURE_NAME] = on | off
> 
>> +file == 2 && $1 ~ /^CONFIG_X86_[A-Z]*_FEATURE_/ {
>> +    on = ($2 == "y");
>> +    if (split($1, fs, "CONFIG_X86_|_FEATURE_") == 3)
>> +        featstat[fs[2], fs[3]] = on;
>> +}
>> +
>> +END {
>> +    sets[1] = "REQUIRED";
>> +    sets[2] = "DISABLED";
>> +
>> +    for (ns in sets) {
>> +        s = sets[ns];
>> +
>> +        printf "/*\n";
>> +        printf " * %s features:\n", s;
>> +        printf " *\n";
>> +        fstr = "";
>> +        for (i = 0; i < ncapints; i++) {
>> +            mask = 0;
>> +            for (j = 0; j < 32; j++) {
>> +                nfeat = i*32 + j;
>> +                feat = feats[nfeat];
>> +                if (feat) {
>> +                    st = !!featstat[s, feat];
>> +                    if (st) {
>> +                        nfstr = fstr " " feat;
>> +                        if (length(nfstr) > 72) {
>> +                            printf " *   %s\n", fstr;
>> +                            nfstr = " " feat;
>> +                        }
>> +                        fstr = nfstr;
>> +                    }
>> +                    mask += st * (2 ^ j);
> 
> nit: This expression can be changed to mask += (2 ^j) and moved inside 
> the 'if (st)' branch. Essentially only add a bit iff that status of the 
> relevant feature in the kconfig is y, which is signified by the value of 
> 'st' variable.

I will do a polish and send v4.

> 
>> +                }
>> +            }
>> +            masks[i] = mask;
>> +        }
>> +        printf " *   %s\n */\n\n", fstr;
>> +
>> +        for (i = 0; i < ncapints; i++) {
>> +            printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];

I should append 'U' here too.

>> +        }
>> +
>> +        printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != 
>> %d)\n\n", s, ncapints;
>> +    }
>> +
>> +    printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
>> +}
> 

Re: [PATCH v3 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Xin Li]

On 6/23/2024 1:28 PM, Brian Gerst wrote:
> On Sat, Jun 22, 2024 at 1:14 PM Xin Li (Intel) <xin@zytor.com> wrote:
>>
>> Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
>> script that generates the required and disabled feature mask header.
>>
>> Suggested-by: Brian Gerst <brgerst@gmail.com>
>> Signed-off-by: Xin Li (Intel) <xin@zytor.com>
>> ---

> Checking NCAPINTS isn't necessary anymore.  It was needed when these
> macros had to be manually updated, but now if cpufeatures.h changes
> this header will be regenerated.
> 
>>          }
>>
>>          printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
>> --
>> 2.45.2
>>
> 
> Otherwise, it looks good.
> 

Do you mind to give a review-by?

Thanks!
     Xin

Re: [PATCH v3B 4/4] x86/cpufeatures: Use AWK to generate {REQUIRED|DISABLED}_MASK_BIT_SET

[Brian Gerst]

On Tue, Jun 25, 2024 at 1:23 AM Xin Li (Intel) <xin@zytor.com> wrote:
>
> Generate macros {REQUIRED|DISABLED}_MASK_BIT_SET in the newly added AWK
> script that generates the required and disabled feature mask header.
>
> Suggested-by: Brian Gerst <brgerst@gmail.com>
> Signed-off-by: Xin Li (Intel) <xin@zytor.com>
> ---
>
> Change since v3A:
> * Use '1U' instead of '1' in feature mask shifting (Andrew Cooper).
>
> Change since v3:
> * Checking NCAPINTS isn't necessary anymore.  It was needed when these
>   macros had to be manually updated, but now if cpufeatures.h changes
>   this header will be regenerated (Brian Gerst).
> ---
>  arch/x86/include/asm/cpufeature.h | 69 -------------------------------
>  arch/x86/tools/featuremasks.awk   |  9 +++-
>  2 files changed, 8 insertions(+), 70 deletions(-)
>
> diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
> index 8332f596ba3c..8161dfb3255c 100644
> --- a/arch/x86/include/asm/cpufeature.h
> +++ b/arch/x86/include/asm/cpufeature.h
> @@ -55,75 +55,6 @@ extern const char * const x86_bug_flags[NBUGINTS*32];
>  #define test_cpu_cap(c, bit)                                           \
>          arch_test_bit(bit, (unsigned long *)((c)->x86_capability))
>
> -/*
> - * There are 32 bits/features in each mask word.  The high bits
> - * (selected with (bit>>5) give us the word number and the low 5
> - * bits give us the bit/feature number inside the word.
> - * (1UL<<((bit)&31) gives us a mask for the feature_bit so we can
> - * see if it is set in the mask word.
> - */
> -#define CHECK_BIT_IN_MASK_WORD(maskname, word, bit)    \
> -       (((bit)>>5)==(word) && (1UL<<((bit)&31) & maskname##word ))
> -
> -/*
> - * {REQUIRED,DISABLED}_MASK_CHECK below may seem duplicated with the
> - * following BUILD_BUG_ON_ZERO() check but when NCAPINTS gets changed, all
> - * header macros which use NCAPINTS need to be changed. The duplicated macro
> - * use causes the compiler to issue errors for all headers so that all usage
> - * sites can be corrected.
> - */
> -#define REQUIRED_MASK_BIT_SET(feature_bit)             \
> -        ( CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  0, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  1, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  2, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  3, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  4, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  5, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  6, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  7, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  8, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK,  9, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 10, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 11, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 12, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 13, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 14, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 15, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 16, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 17, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 18, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 19, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 20, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(REQUIRED_MASK, 21, feature_bit) ||    \
> -          REQUIRED_MASK_CHECK                                    ||    \
> -          BUILD_BUG_ON_ZERO(NCAPINTS != 22))
> -
> -#define DISABLED_MASK_BIT_SET(feature_bit)                             \
> -        ( CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  0, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  1, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  2, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  3, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  4, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  5, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  6, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  7, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  8, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK,  9, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 10, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 11, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 12, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 13, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 14, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 15, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 16, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 17, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 18, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 19, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 20, feature_bit) ||    \
> -          CHECK_BIT_IN_MASK_WORD(DISABLED_MASK, 21, feature_bit) ||    \
> -          DISABLED_MASK_CHECK                                    ||    \
> -          BUILD_BUG_ON_ZERO(NCAPINTS != 22))
> -
>  #define cpu_has(c, bit)                                                        \
>         (__builtin_constant_p(bit) && REQUIRED_MASK_BIT_SET(bit) ? 1 :  \
>          test_cpu_cap(c, bit))
> diff --git a/arch/x86/tools/featuremasks.awk b/arch/x86/tools/featuremasks.awk
> index 989b021e73d3..e0383683e630 100755
> --- a/arch/x86/tools/featuremasks.awk
> +++ b/arch/x86/tools/featuremasks.awk
> @@ -77,7 +77,14 @@ END {
>                         printf "#define %s_MASK%d\t0x%08x\n", s, i, masks[i];
>                 }
>
> -               printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints;
> +               printf "\n#define %s_MASK_BIT_SET(x)\t\t\t\\\n", s;
> +               printf "\t((\t\t\t\t\t";
> +               for (i = 0; i < ncapints; i++) {
> +                       if (masks[i])
> +                               printf "\t\\\n\t\t((x) >> 5) == %2d ? %s_MASK%d :", i, s, i;
> +               }
> +               printf " 0\t\\\n";
> +               printf "\t) & (1U << ((x) & 31)))\n";
>         }
>
>         printf "#endif /* _ASM_X86_FEATUREMASKS_H */\n";
> --
> 2.45.2
>

Reviewed-by: Brian Gerst <brgerst@gmail.com>