From 424e23fd6c30ec204c1c77919066ae777577a4f9 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Wed, 10 May 2023 08:57:12 +0200 Subject: x86/Kconfig: Make X86_FEATURE_NAMES non-configurable in prompt 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 a first step, make X86_FEATURE_NAMES disappear from Kconfig. So, as X86_FEATURE_NAMES defaults to yes, to disable it, one now needs to modify the .config file before compiling the kernel. Suggested-by: Borislav Petkov Signed-off-by: Lukas Bulwahn Signed-off-by: Borislav Petkov (AMD) Link: https://lore.kernel.org/all/20230509084007.24373-1-lukas.bulwahn@gmail.com/ --- arch/x86/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 53bab123a8ee..a7db116e429a 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -442,7 +442,7 @@ 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 + bool default y help This option compiles in a table of x86 feature bits and corresponding -- cgit v1.2.3 From 7583e8fbdc49a4dbd916d14863cf1deeddb982f9 Mon Sep 17 00:00:00 2001 From: Lukas Bulwahn Date: Wed, 10 May 2023 08:57:13 +0200 Subject: x86/cpu: Remove X86_FEATURE_NAMES 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 Signed-off-by: Lukas Bulwahn Signed-off-by: Borislav Petkov (AMD) 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 --- 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(-) (limited to 'arch') 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"); -- cgit v1.2.3 From f220125b999b2c9694149c6bda2798d8096f47ed Mon Sep 17 00:00:00 2001 From: "Borislav Petkov (AMD)" Date: Mon, 15 May 2023 16:07:26 +0200 Subject: x86/retbleed: Add __x86_return_thunk alignment checks Add a linker assertion and compute the 0xcc padding dynamically so that __x86_return_thunk is always cacheline-aligned. Leave the SYM_START() macro in as the untraining doesn't need ENDBR annotations anyway. Suggested-by: Andrew Cooper Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Andrew Cooper Link: https://lore.kernel.org/r/20230515140726.28689-1-bp@alien8.de --- arch/x86/kernel/vmlinux.lds.S | 4 ++++ arch/x86/lib/retpoline.S | 2 +- 2 files changed, 5 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/x86/kernel/vmlinux.lds.S b/arch/x86/kernel/vmlinux.lds.S index 25f155205770..03c885d3640f 100644 --- a/arch/x86/kernel/vmlinux.lds.S +++ b/arch/x86/kernel/vmlinux.lds.S @@ -508,4 +508,8 @@ INIT_PER_CPU(irq_stack_backing_store); "fixed_percpu_data is not at start of per-cpu area"); #endif +#ifdef CONFIG_RETHUNK +. = ASSERT((__x86_return_thunk & 0x3f) == 0, "__x86_return_thunk not cacheline-aligned"); +#endif + #endif /* CONFIG_X86_64 */ diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S index b3b1e376dce8..3fd066d42ec0 100644 --- a/arch/x86/lib/retpoline.S +++ b/arch/x86/lib/retpoline.S @@ -143,7 +143,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array) * from re-poisioning the BTB prediction. */ .align 64 - .skip 63, 0xcc + .skip 64 - (__x86_return_thunk - zen_untrain_ret), 0xcc SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE) ANNOTATE_NOENDBR /* -- cgit v1.2.3