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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 <josh@joshtriplett.org>
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parent
39f838e06f
commit
9def39be4e
6 changed files with 71 additions and 32 deletions
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@ -136,6 +136,7 @@ config X86
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select HAVE_ACPI_APEI if ACPI
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select HAVE_ACPI_APEI_NMI if ACPI
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select ACPI_LEGACY_TABLES_LOOKUP if ACPI
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select X86_FEATURE_NAMES if PROC_FS
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config INSTRUCTION_DECODER
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def_bool y
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@ -313,6 +314,17 @@ config SMP
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If you don't know what to do here, say N.
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config X86_FEATURE_NAMES
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bool "Processor feature human-readable names" if EMBEDDED
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default y
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---help---
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This option compiles in a table of x86 feature bits and corresponding
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names. This is required to support /proc/cpuinfo and a few kernel
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messages. You can disable this to save space, at the expense of
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making those few kernel messages show numeric feature bits instead.
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If in doubt, say Y.
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config X86_X2APIC
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bool "Support x2apic"
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depends on X86_LOCAL_APIC && X86_64 && IRQ_REMAP
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@ -35,12 +35,14 @@ setup-y += video-vesa.o
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setup-y += video-bios.o
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targets += $(setup-y)
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hostprogs-y := mkcpustr tools/build
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hostprogs-y := tools/build
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hostprogs-$(CONFIG_X86_FEATURE_NAMES) += mkcpustr
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HOST_EXTRACFLAGS += -I$(srctree)/tools/include \
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-include include/generated/autoconf.h \
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-D__EXPORTED_HEADERS__
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ifdef CONFIG_X86_FEATURE_NAMES
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$(obj)/cpu.o: $(obj)/cpustr.h
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quiet_cmd_cpustr = CPUSTR $@
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@ -48,6 +50,7 @@ quiet_cmd_cpustr = CPUSTR $@
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targets += cpustr.h
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$(obj)/cpustr.h: $(obj)/mkcpustr FORCE
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$(call if_changed,cpustr)
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endif
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# ---------------------------------------------------------------------------
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@ -16,7 +16,9 @@
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*/
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#include "boot.h"
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#ifdef CONFIG_X86_FEATURE_NAMES
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#include "cpustr.h"
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#endif
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static char *cpu_name(int level)
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{
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@ -32,32 +34,13 @@ static char *cpu_name(int level)
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}
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}
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int validate_cpu(void)
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static void show_cap_strs(u32 *err_flags)
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{
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u32 *err_flags;
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int cpu_level, req_level;
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const unsigned char *msg_strs;
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check_cpu(&cpu_level, &req_level, &err_flags);
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if (cpu_level < req_level) {
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printf("This kernel requires an %s CPU, ",
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cpu_name(req_level));
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printf("but only detected an %s CPU.\n",
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cpu_name(cpu_level));
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return -1;
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}
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if (err_flags) {
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int i, j;
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puts("This kernel requires the following features "
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"not present on the CPU:\n");
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msg_strs = (const unsigned char *)x86_cap_strs;
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#ifdef CONFIG_X86_FEATURE_NAMES
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const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
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for (i = 0; i < NCAPINTS; i++) {
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u32 e = err_flags[i];
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for (j = 0; j < 32; j++) {
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if (msg_strs[0] < i ||
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(msg_strs[0] == i && msg_strs[1] < j)) {
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@ -77,6 +60,37 @@ int validate_cpu(void)
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e >>= 1;
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}
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}
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#else
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for (i = 0; i < NCAPINTS; i++) {
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u32 e = err_flags[i];
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for (j = 0; j < 32; j++) {
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if (e & 1)
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printf("%d:%d ", i, j);
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e >>= 1;
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}
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}
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#endif
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}
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int validate_cpu(void)
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{
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u32 *err_flags;
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int cpu_level, req_level;
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check_cpu(&cpu_level, &req_level, &err_flags);
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if (cpu_level < req_level) {
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printf("This kernel requires an %s CPU, ",
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cpu_name(req_level));
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printf("but only detected an %s CPU.\n",
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cpu_name(cpu_level));
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return -1;
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}
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if (err_flags) {
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puts("This kernel requires the following features "
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"not present on the CPU:\n");
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show_cap_strs(err_flags);
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putchar('\n');
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return -1;
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} else {
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@ -250,8 +250,15 @@
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#include <asm/asm.h>
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#include <linux/bitops.h>
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#ifdef CONFIG_X86_FEATURE_NAMES
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extern const char * const x86_cap_flags[NCAPINTS*32];
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extern const char * const x86_power_flags[32];
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#define X86_CAP_FMT "%s"
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#define x86_cap_flag(flag) x86_cap_flags[flag]
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#else
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#define X86_CAP_FMT "%d:%d"
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#define x86_cap_flag(flag) ((flag) >> 5), ((flag) & 31)
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#endif
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/*
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* In order to save room, we index into this array by doing
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@ -13,11 +13,12 @@ nostackp := $(call cc-option, -fno-stack-protector)
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CFLAGS_common.o := $(nostackp)
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obj-y := intel_cacheinfo.o scattered.o topology.o
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obj-y += capflags.o powerflags.o common.o
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obj-y += common.o
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obj-y += rdrand.o
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obj-y += match.o
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obj-$(CONFIG_PROC_FS) += proc.o
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obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
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obj-$(CONFIG_X86_32) += bugs.o
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obj-$(CONFIG_X86_64) += bugs_64.o
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@ -50,6 +51,7 @@ obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o perf_event_amd_ibs.o
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obj-$(CONFIG_HYPERVISOR_GUEST) += vmware.o hypervisor.o mshyperv.o
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ifdef CONFIG_X86_FEATURE_NAMES
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quiet_cmd_mkcapflags = MKCAP $@
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cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@
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@ -58,3 +60,4 @@ cpufeature = $(src)/../../include/asm/cpufeature.h
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targets += capflags.c
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$(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE
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$(call if_changed,mkcapflags)
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endif
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@ -346,8 +346,8 @@ static void filter_cpuid_features(struct cpuinfo_x86 *c, bool warn)
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continue;
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printk(KERN_WARNING
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"CPU: CPU feature %s disabled, no CPUID level 0x%x\n",
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x86_cap_flags[df->feature], df->level);
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"CPU: CPU feature " X86_CAP_FMT " disabled, no CPUID level 0x%x\n",
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x86_cap_flag(df->feature), df->level);
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}
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}
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