The following commit has been merged into the x86/cpu branch of tip: Commit-ID: 7a7bd24a0ca02dfe68bd8a7a567b3da3b716bd8d Gitweb: https://git.kernel.org/tip/7a7bd24a0ca02dfe68bd8a7a567b3da3b716bd8d Author: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> AuthorDate: Wed, 05 Mar 2025 10:47:22 -08:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Mon, 10 Mar 2025 09:02:47 +01:00 x86/cpufeatures: Generate the <asm/cpufeaturemasks.h> header based on build config Introduce an AWK script to auto-generate the <asm/cpufeaturemasks.h> header with required and disabled feature masks based on <asm/cpufeatures.h> and the 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 ] [ mingo: Improved changelog and comments ] Signed-off-by: H. Peter Anvin (Intel) <hpa@xxxxxxxxx> Signed-off-by: Xin Li (Intel) <xin@xxxxxxxxx> Signed-off-by: Borislav Petkov (AMD) <bp@xxxxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Reviewed-by: Nikolay Borisov <nik.borisov@xxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20250305184725.3341760-3-xin@xxxxxxxxx --- arch/x86/Makefile | 15 +++++- 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/cpufeaturemasks.awk | 81 +++++++++++++++++++++++++++++- 9 files changed, 105 insertions(+), 12 deletions(-) create mode 100755 arch/x86/tools/cpufeaturemasks.awk diff --git a/arch/x86/Makefile b/arch/x86/Makefile index 8120085..420f086 100644 --- a/arch/x86/Makefile +++ b/arch/x86/Makefile @@ -265,6 +265,21 @@ archheaders: $(Q)$(MAKE) $(build)=arch/x86/entry/syscalls all ### +# <asm/cpufeaturemasks.h> header generation + +cpufeaturemasks.hdr := arch/x86/include/generated/asm/cpufeaturemasks.h +cpufeaturemasks.awk := $(srctree)/arch/x86/tools/cpufeaturemasks.awk +cpufeatures_hdr := $(srctree)/arch/x86/include/asm/cpufeatures.h +targets += $(cpufeaturemasks.hdr) +quiet_cmd_gen_featuremasks = GEN $@ + cmd_gen_featuremasks = $(AWK) -f $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) > $@ + +$(cpufeaturemasks.hdr): $(cpufeaturemasks.awk) $(cpufeatures_hdr) $(KCONFIG_CONFIG) FORCE + $(shell mkdir -p $(dir $@)) + $(call if_changed,gen_featuremasks) +archprepare: $(cpufeaturemasks.hdr) + +### # Kernel objects libs-y += arch/x86/lib/ diff --git a/arch/x86/boot/cpucheck.c b/arch/x86/boot/cpucheck.c index 0aae4d4..f82de8d 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/cpufeaturemasks.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 d75237b..0cabdac 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 da0ccc5..22d730b 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/cpufeaturemasks.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 58f4dde..4566000 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 += cpufeaturemasks.h generic-y += early_ioremap.h generic-y += fprobe.h diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index e955da3..d54db88 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/cpufeaturemasks.h> enum cpuid_leafs { diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 8770dc1..c0462be 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 1258a58..37ad437 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/cpufeaturemasks.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/cpufeaturemasks.awk b/arch/x86/tools/cpufeaturemasks.awk new file mode 100755 index 0000000..59757ca --- /dev/null +++ b/arch/x86/tools/cpufeaturemasks.awk @@ -0,0 +1,81 @@ +#!/usr/bin/awk +# +# Convert cpufeatures.h to a list of compile-time masks +# Note: this blithely assumes that each word has at least one +# feature defined in it; if not, something else is wrong! +# + +BEGIN { + printf "#ifndef _ASM_X86_CPUFEATUREMASKS_H\n"; + printf "#define _ASM_X86_CPUFEATUREMASKS_H\n\n"; + + file = 0 +} + +FNR == 1 { + ++file; + + # arch/x86/include/asm/cpufeatures.h + if (file == 1) + FS = "[ \t()*+]+"; + + # .config + if (file == 2) + FS = "="; +} + +# Create a dictionary of sorts, containing all defined feature bits +file == 1 && $1 ~ /^#define$/ && $2 ~ /^X86_FEATURE_/ { + nfeat = $3 * $4 + $5; + feat = $2; + sub(/^X86_FEATURE_/, "", feat); + feats[nfeat] = feat; +} +file == 1 && $1 ~ /^#define$/ && $2 == "NCAPINTS" { + ncapints = int($3); +} + +# Create a dictionary featstat[REQUIRED|DISABLED, FEATURE_NAME] = on | off +file == 2 && $1 ~ /^CONFIG_X86_(REQUIRED|DISABLED)_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++) { + feat = feats[i*32 + j]; + if (featstat[s, feat]) { + nfstr = fstr " " feat; + if (length(nfstr) > 72) { + printf " * %s\n", fstr; + nfstr = " " feat; + } + fstr = nfstr; + mask += (2 ^ j); + } + } + masks[i] = mask; + } + printf " * %s\n */\n", fstr; + + for (i = 0; i < ncapints; i++) + printf "#define %s_MASK%d\t0x%08xU\n", s, i, masks[i]; + + printf "#define %s_MASK_CHECK BUILD_BUG_ON_ZERO(NCAPINTS != %d)\n\n", s, ncapints; + } + + printf "#endif /* _ASM_X86_CPUFEATUREMASKS_H */\n"; +}
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