From 9def39be4e960917fcb80514ff23651f9ec97193 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Wed, 30 Oct 2013 08:09:45 -0700 Subject: [PATCH] x86: Support compiling out human-friendly processor feature names The table mapping CPUID bits to human-readable strings takes up a non-trivial amount of space, and only exists to support /proc/cpuinfo and a couple of kernel messages. Since programs depend on the format of /proc/cpuinfo, force inclusion of the table when building with /proc support; otherwise, support omitting that table to save space, in which case the kernel messages will print features numerically instead. In addition to saving 1408 bytes out of vmlinux, this also saves 1373 bytes out of the uncompressed setup code, which contributes directly to the size of bzImage. Signed-off-by: Josh Triplett --- arch/x86/Kconfig | 12 ++++++ arch/x86/boot/Makefile | 7 +++- arch/x86/boot/cpu.c | 68 +++++++++++++++++++------------ arch/x86/include/asm/cpufeature.h | 7 ++++ arch/x86/kernel/cpu/Makefile | 5 ++- arch/x86/kernel/cpu/common.c | 4 +- 6 files changed, 71 insertions(+), 32 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5d0bf1aa9dc..a11f27c4266 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -136,6 +136,7 @@ config X86 select HAVE_ACPI_APEI if ACPI select HAVE_ACPI_APEI_NMI if ACPI select ACPI_LEGACY_TABLES_LOOKUP if ACPI + select X86_FEATURE_NAMES if PROC_FS config INSTRUCTION_DECODER def_bool y @@ -313,6 +314,17 @@ config SMP If you don't know what to do here, say N. +config X86_FEATURE_NAMES + bool "Processor feature human-readable names" if EMBEDDED + default y + ---help--- + This option compiles in a table of x86 feature bits and corresponding + names. This is required to support /proc/cpuinfo and a few kernel + messages. You can disable this to save space, at the expense of + making those few kernel messages show numeric feature bits instead. + + If in doubt, say Y. + config X86_X2APIC bool "Support x2apic" depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile index dbe8dd2fe24..5b016e2498f 100644 --- a/arch/x86/boot/Makefile +++ b/arch/x86/boot/Makefile @@ -35,19 +35,22 @@ setup-y += video-vesa.o setup-y += video-bios.o targets += $(setup-y) -hostprogs-y := mkcpustr tools/build +hostprogs-y := tools/build +hostprogs-$(CONFIG_X86_FEATURE_NAMES) += mkcpustr HOST_EXTRACFLAGS += -I$(srctree)/tools/include \ -include include/generated/autoconf.h \ -D__EXPORTED_HEADERS__ +ifdef CONFIG_X86_FEATURE_NAMES $(obj)/cpu.o: $(obj)/cpustr.h quiet_cmd_cpustr = CPUSTR $@ cmd_cpustr = $(obj)/mkcpustr > $@ -targets += cpustr.h +targets += cpustr.h $(obj)/cpustr.h: $(obj)/mkcpustr FORCE $(call if_changed,cpustr) +endif # --------------------------------------------------------------------------- diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c index 6ec6bb6e995..29207f69ae8 100644 --- a/arch/x86/boot/cpu.c +++ b/arch/x86/boot/cpu.c @@ -16,7 +16,9 @@ */ #include "boot.h" +#ifdef CONFIG_X86_FEATURE_NAMES #include "cpustr.h" +#endif static char *cpu_name(int level) { @@ -32,11 +34,48 @@ static char *cpu_name(int level) } } +static void show_cap_strs(u32 *err_flags) +{ + int i, j; +#ifdef CONFIG_X86_FEATURE_NAMES + const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs; + for (i = 0; i < NCAPINTS; i++) { + u32 e = err_flags[i]; + for (j = 0; j < 32; j++) { + if (msg_strs[0] < i || + (msg_strs[0] == i && msg_strs[1] < j)) { + /* Skip to the next string */ + msg_strs += 2; + while (*msg_strs++) + ; + } + if (e & 1) { + if (msg_strs[0] == i && + msg_strs[1] == j && + msg_strs[2]) + printf("%s ", msg_strs+2); + else + printf("%d:%d ", i, j); + } + e >>= 1; + } + } +#else + for (i = 0; i < NCAPINTS; i++) { + u32 e = err_flags[i]; + for (j = 0; j < 32; j++) { + if (e & 1) + printf("%d:%d ", i, j); + e >>= 1; + } + } +#endif +} + int validate_cpu(void) { u32 *err_flags; int cpu_level, req_level; - const unsigned char *msg_strs; check_cpu(&cpu_level, &req_level, &err_flags); @@ -49,34 +88,9 @@ int validate_cpu(void) } if (err_flags) { - int i, j; puts("This kernel requires the following features " "not present on the CPU:\n"); - - msg_strs = (const unsigned char *)x86_cap_strs; - - for (i = 0; i < NCAPINTS; i++) { - u32 e = err_flags[i]; - - for (j = 0; j < 32; j++) { - if (msg_strs[0] < i || - (msg_strs[0] == i && msg_strs[1] < j)) { - /* Skip to the next string */ - msg_strs += 2; - while (*msg_strs++) - ; - } - if (e & 1) { - if (msg_strs[0] == i && - msg_strs[1] == j && - msg_strs[2]) - printf("%s ", msg_strs+2); - else - printf("%d:%d ", i, j); - } - e >>= 1; - } - } + show_cap_strs(err_flags); putchar('\n'); return -1; } else { diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index bb9b258d60e..516903b98e0 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -250,8 +250,15 @@ #include #include +#ifdef CONFIG_X86_FEATURE_NAMES extern const char * const x86_cap_flags[NCAPINTS*32]; extern const char * const x86_power_flags[32]; +#define X86_CAP_FMT "%s" +#define x86_cap_flag(flag) x86_cap_flags[flag] +#else +#define X86_CAP_FMT "%d:%d" +#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31) +#endif /* * In order to save room, we index into this array by doing diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 64038d842c5..77dcab27771 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -13,11 +13,12 @@ nostackp := $(call cc-option, -fno-stack-protector) CFLAGS_common.o := $(nostackp) obj-y := intel_cacheinfo.o scattered.o topology.o -obj-y += capflags.o powerflags.o common.o +obj-y += common.o obj-y += rdrand.o obj-y += match.o obj-$(CONFIG_PROC_FS) += proc.o +obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o obj-$(CONFIG_X86_32) += bugs.o obj-$(CONFIG_X86_64) += bugs_64.o @@ -50,6 +51,7 @@ obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o perf_event_amd_ibs.o obj-$(CONFIG_HYPERVISOR_GUEST) += vmware.o hypervisor.o mshyperv.o +ifdef CONFIG_X86_FEATURE_NAMES quiet_cmd_mkcapflags = MKCAP $@ cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@ @@ -58,3 +60,4 @@ cpufeature = $(src)/../../include/asm/cpufeature.h targets += capflags.c $(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE $(call if_changed,mkcapflags) +endif diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index e4ab2b42bd6..c649f236e28 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -346,8 +346,8 @@ static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn) continue; printk(KERN_WARNING - "CPU: CPU feature %s disabled, no CPUID level 0x%x\n", - x86_cap_flags[df->feature], df->level); + "CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n", + x86_cap_flag(df->feature), df->level); } } -- 2.41.0