[PATCH 2/2] x86: always build with X86_FEATURE_NAMES functionality
From: Lukas Bulwahn
Date: Wed May 10 2023 - 02:57:44 EST
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 is hardly tested, remove this config and the whole
ifdeffery in the source code.
Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@xxxxxxxxx/
Suggested-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@xxxxxxxxx>
---
arch/x86/Kconfig | 12 ------------
arch/x86/Kconfig.cpu | 2 +-
arch/x86/boot/Makefile | 2 --
arch/x86/boot/cpu.c | 13 -------------
arch/x86/include/asm/cpufeature.h | 5 -----
arch/x86/kernel/cpu/Makefile | 4 +---
arch/x86/kernel/cpu/common.c | 4 ----
7 files changed, 2 insertions(+), 40 deletions(-)
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a7db116e429a..f6aa7e0ca47d 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -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)
diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu
index 542377cd419d..00468adf180f 100644
--- a/arch/x86/Kconfig.cpu
+++ b/arch/x86/Kconfig.cpu
@@ -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
diff --git a/arch/x86/boot/Makefile b/arch/x86/boot/Makefile
index 9e38ffaadb5d..f33e45ed1437 100644
--- a/arch/x86/boot/Makefile
+++ b/arch/x86/boot/Makefile
@@ -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
$(call if_changed,cpustr)
-endif
targets += cpustr.h
# ---------------------------------------------------------------------------
diff --git a/arch/x86/boot/cpu.c b/arch/x86/boot/cpu.c
index 0bbf4f3707d2..feb6dbd7ca86 100644
--- a/arch/x86/boot/cpu.c
+++ b/arch/x86/boot/cpu.c
@@ -14,9 +14,7 @@
*/
#include "boot.h"
-#ifdef CONFIG_X86_FEATURE_NAMES
#include "cpustr.h"
-#endif
static char *cpu_name(int level)
{
@@ -35,7 +33,6 @@ static char *cpu_name(int level)
static void show_cap_strs(u32 *err_flags)
{
int i, j;
-#ifdef CONFIG_X86_FEATURE_NAMES
const unsigned char *msg_strs = (const unsigned char *)x86_cap_strs;
for (i = 0; i < NCAPINTS; i++) {
u32 e = err_flags[i];
@@ -58,16 +55,6 @@ static void show_cap_strs(u32 *err_flags)
e >>= 1;
}
}
-#else
- for (i = 0; i < NCAPINTS; i++) {
- u32 e = err_flags[i];
- for (j = 0; j < 32; j++) {
- if (e & 1)
- printf("%d:%d ", i, j);
- e >>= 1;
- }
- }
-#endif
}
int validate_cpu(void)
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h
index ce0c8f7d3218..a26bebbdff87 100644
--- a/arch/x86/include/asm/cpufeature.h
+++ b/arch/x86/include/asm/cpufeature.h
@@ -38,15 +38,10 @@ enum cpuid_leafs
#define X86_CAP_FMT_NUM "%d:%d"
#define x86_cap_flag_num(flag) ((flag) >> 5), ((flag) & 31)
-#ifdef CONFIG_X86_FEATURE_NAMES
extern const char * const x86_cap_flags[NCAPINTS*32];
extern const char * const x86_power_flags[32];
#define X86_CAP_FMT "%s"
#define x86_cap_flag(flag) x86_cap_flags[flag]
-#else
-#define X86_CAP_FMT X86_CAP_FMT_NUM
-#define x86_cap_flag x86_cap_flag_num
-#endif
/*
* In order to save room, we index into this array by doing
diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile
index d7e3ceaf75c1..4350f6bfc064 100644
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -27,7 +27,7 @@ obj-y += cpuid-deps.o
obj-y += umwait.o
obj-$(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
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 80710a68ef7d..849ed7e2a726 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -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");
--
2.17.1