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x86/cpu: Remove X86_FEATURE_NAMES

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While discussing to change the visibility of X86_FEATURE_NAMES (see Link)
in order to remove CONFIG_EMBEDDED, Boris suggested to simply make the
X86_FEATURE_NAMES functionality unconditional.

As the need for really tiny kernel images has gone away and kernel images
with !X86_FEATURE_NAMES are hardly tested, remove this config and the whole
ifdeffery in the source code.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/
Link: https://lore.kernel.org/r/20230510065713.10996-3-lukas.bulwahn@gmail.com
This commit is contained in:
Lukas Bulwahn 2023-05-10 08:57:13 +02:00 committed by Borislav Petkov (AMD)
parent 424e23fd6c
commit 7583e8fbdc
7 changed files with 2 additions and 40 deletions
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12
arch/x86/Kconfig
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@ -291,7 +291,6 @@ config X86
select TRACE_IRQFLAGS_NMI_SUPPORT
select USER_STACKTRACE_SUPPORT
select HAVE_ARCH_KCSAN if X86_64
select X86_FEATURE_NAMES if PROC_FS
select PROC_PID_ARCH_STATUS if PROC_FS
select HAVE_ARCH_NODE_DEV_GROUP if X86_SGX
select FUNCTION_ALIGNMENT_16B if X86_64 || X86_ALIGNMENT_16
@ -441,17 +440,6 @@ config SMP
If you don't know what to do here, say N.
config X86_FEATURE_NAMES
bool
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 || HYPERVISOR_GUEST)

2
arch/x86/Kconfig.cpu
View File

@ -389,7 +389,7 @@ config IA32_FEAT_CTL
config X86_VMX_FEATURE_NAMES
def_bool y
depends on IA32_FEAT_CTL && X86_FEATURE_NAMES
depends on IA32_FEAT_CTL
menuconfig PROCESSOR_SELECT
bool "Supported processor vendors" if EXPERT

2
arch/x86/boot/Makefile
View File

@ -55,14 +55,12 @@ 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 > $@
$(obj)/cpustr.h: $(obj)/mkcpustr FORCE
$(call if_changed,cpustr)
endif
targets += cpustr.h
# ---------------------------------------------------------------------------

13
arch/x86/boot/cpu.c
View File

@ -14,9 +14,7 @@
*/
#include "boot.h"
#ifdef CONFIG_X86_FEATURE_NAMES
#include "cpustr.h"
#endif
static char *cpu_name(int level)
{
@ -35,7 +33,6 @@ 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];
@ -58,16 +55,6 @@ static void show_cap_strs(u32 *err_flags)
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)

5
arch/x86/include/asm/cpufeature.h
View File

@ -38,15 +38,10 @@ enum cpuid_leafs
#define X86_CAP_FMT_NUM "%d:%d"
#define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
#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 X86_CAP_FMT_NUM
#define x86_cap_flag x86_cap_flag_num
#endif
/*
* In order to save room, we index into this array by doing

4
arch/x86/kernel/cpu/Makefile
View File

@ -27,7 +27,7 @@ obj-y += cpuid-deps.o
obj-y += umwait.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
obj-y += capflags.o powerflags.o
obj-$(CONFIG_IA32_FEAT_CTL) += feat_ctl.o
ifdef CONFIG_CPU_SUP_INTEL
@ -54,7 +54,6 @@ obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o
obj-$(CONFIG_HYPERVISOR_GUEST) += vmware.o hypervisor.o mshyperv.o
obj-$(CONFIG_ACRN_GUEST) += acrn.o
ifdef CONFIG_X86_FEATURE_NAMES
quiet_cmd_mkcapflags = MKCAP $@
cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $@ $^
@ -63,5 +62,4 @@ vmxfeature = $(src)/../../include/asm/vmxfeatures.h
$(obj)/capflags.c: $(cpufeature) $(vmxfeature) $(src)/mkcapflags.sh FORCE
$(call if_changed,mkcapflags)
endif
targets += capflags.c

4
arch/x86/kernel/cpu/common.c
View File

@ -1502,12 +1502,10 @@ static void __init cpu_parse_early_param(void)
if (!kstrtouint(opt, 10, &bit)) {
if (bit < NCAPINTS * 32) {
#ifdef CONFIG_X86_FEATURE_NAMES
/* empty-string, i.e., ""-defined feature flags */
if (!x86_cap_flags[bit])
pr_cont(" " X86_CAP_FMT_NUM, x86_cap_flag_num(bit));
else
#endif
pr_cont(" " X86_CAP_FMT, x86_cap_flag(bit));
setup_clear_cpu_cap(bit);
@ -1520,7 +1518,6 @@ static void __init cpu_parse_early_param(void)
continue;
}
#ifdef CONFIG_X86_FEATURE_NAMES
for (bit = 0; bit < 32 * NCAPINTS; bit++) {
if (!x86_cap_flag(bit))
continue;
@ -1537,7 +1534,6 @@ static void __init cpu_parse_early_param(void)
if (!found)
pr_cont(" (unknown: %s)", opt);
#endif
}
pr_cont("\n");