Commit 9def39be authored by Josh Triplett's avatar Josh Triplett

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: default avatarJosh Triplett <josh@joshtriplett.org>
parent 39f838e0
......@@ -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
......
......@@ -35,12 +35,14 @@ 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 $@
......@@ -48,6 +50,7 @@ quiet_cmd_cpustr = CPUSTR $@
targets += cpustr.h
$(obj)/cpustr.h: $(obj)/mkcpustr FORCE
$(call if_changed,cpustr)
endif
# ---------------------------------------------------------------------------
......
......@@ -16,7 +16,9 @@
*/
#include "boot.h"
#ifdef CONFIG_X86_FEATURE_NAMES
#include "cpustr.h"
#endif
static char *cpu_name(int level)
{
......@@ -32,32 +34,13 @@ static char *cpu_name(int level)
}
}
int validate_cpu(void)
static void show_cap_strs(u32 *err_flags)
{
u32 *err_flags;
int cpu_level, req_level;
const unsigned char *msg_strs;
check_cpu(&cpu_level, &req_level, &err_flags);
if (cpu_level < req_level) {
printf("This kernel requires an %s CPU, ",
cpu_name(req_level));
printf("but only detected an %s CPU.\n",
cpu_name(cpu_level));
return -1;
}
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;
#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)) {
......@@ -77,6 +60,37 @@ int validate_cpu(void)
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;
check_cpu(&cpu_level, &req_level, &err_flags);
if (cpu_level < req_level) {
printf("This kernel requires an %s CPU, ",
cpu_name(req_level));
printf("but only detected an %s CPU.\n",
cpu_name(cpu_level));
return -1;
}
if (err_flags) {
puts("This kernel requires the following features "
"not present on the CPU:\n");
show_cap_strs(err_flags);
putchar('\n');
return -1;
} else {
......
......@@ -250,8 +250,15 @@
#include <asm/asm.h>
#include <linux/bitops.h>
#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
......
......@@ -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
......@@ -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);
}
}
......
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