diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index a3c31b784edc..948707a3615e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -2564,15 +2564,14 @@ config MITIGATION_CALL_DEPTH_TRACKING default y help Compile the kernel with call depth tracking to mitigate the Intel - SKL Return-Speculation-Buffer (RSB) underflow issue. The - mitigation is off by default and needs to be enabled on the - kernel command line via the retbleed=stuff option. For - non-affected systems the overhead of this option is marginal as - the call depth tracking is using run-time generated call thunks - in a compiler generated padding area and call patching. This - increases text size by ~5%. For non affected systems this space - is unused. On affected SKL systems this results in a significant - performance gain over the IBRS mitigation. + SKL Return-Stack-Buffer (RSB) underflow issue. The mitigation is off + by default and needs to be enabled on the kernel command line via the + retbleed=stuff option. For non-affected systems the overhead of this + option is marginal as the call depth tracking is using run-time + generated call thunks in a compiler generated padding area and call + patching. This increases text size by ~5%. For non affected systems + this space is unused. On affected SKL systems this results in a + significant performance gain over the IBRS mitigation. config CALL_THUNKS_DEBUG bool "Enable call thunks and call depth tracking debugging" diff --git a/arch/x86/include/asm/cpuid.h b/arch/x86/include/asm/cpuid.h index ca4243318aad..239b9ba5c398 100644 --- a/arch/x86/include/asm/cpuid.h +++ b/arch/x86/include/asm/cpuid.h @@ -6,6 +6,8 @@ #ifndef _ASM_X86_CPUID_H #define _ASM_X86_CPUID_H +#include + #include struct cpuid_regs { @@ -20,11 +22,11 @@ enum cpuid_regs_idx { }; #ifdef CONFIG_X86_32 -extern int have_cpuid_p(void); +bool have_cpuid_p(void); #else -static inline int have_cpuid_p(void) +static inline bool have_cpuid_p(void) { - return 1; + return true; } #endif static inline void native_cpuid(unsigned int *eax, unsigned int *ebx, diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 02637365d1a9..06a516f6795b 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -276,21 +276,13 @@ static int __init x86_noinvpcid_setup(char *s) } early_param("noinvpcid", x86_noinvpcid_setup); -#ifdef CONFIG_X86_32 -static int cachesize_override = -1; -static int disable_x86_serial_nr = 1; - -static int __init cachesize_setup(char *str) -{ - get_option(&str, &cachesize_override); - return 1; -} -__setup("cachesize=", cachesize_setup); - /* Standard macro to see if a specific flag is changeable */ -static inline int flag_is_changeable_p(u32 flag) +static inline bool flag_is_changeable_p(unsigned long flag) { - u32 f1, f2; + unsigned long f1, f2; + + if (!IS_ENABLED(CONFIG_X86_32)) + return true; /* * Cyrix and IDT cpus allow disabling of CPUID @@ -313,11 +305,22 @@ static inline int flag_is_changeable_p(u32 flag) : "=&r" (f1), "=&r" (f2) : "ir" (flag)); - return ((f1^f2) & flag) != 0; + return (f1 ^ f2) & flag; } +#ifdef CONFIG_X86_32 +static int cachesize_override = -1; +static int disable_x86_serial_nr = 1; + +static int __init cachesize_setup(char *str) +{ + get_option(&str, &cachesize_override); + return 1; +} +__setup("cachesize=", cachesize_setup); + /* Probe for the CPUID instruction */ -int have_cpuid_p(void) +bool have_cpuid_p(void) { return flag_is_changeable_p(X86_EFLAGS_ID); } @@ -349,10 +352,6 @@ static int __init x86_serial_nr_setup(char *s) } __setup("serialnumber", x86_serial_nr_setup); #else -static inline int flag_is_changeable_p(u32 flag) -{ - return 1; -} static inline void squash_the_stupid_serial_number(struct cpuinfo_x86 *c) { } @@ -1088,7 +1087,6 @@ void get_cpu_address_sizes(struct cpuinfo_x86 *c) static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) { -#ifdef CONFIG_X86_32 int i; /* @@ -1109,7 +1107,6 @@ static void identify_cpu_without_cpuid(struct cpuinfo_x86 *c) break; } } -#endif } #define NO_SPECULATION BIT(0)