diff options
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/fsgsbase.h | 47 | ||||
| -rw-r--r-- | arch/x86/include/asm/inst.h | 15 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 6 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/hwcap2.h | 3 |
4 files changed, 58 insertions, 13 deletions
diff --git a/arch/x86/include/asm/fsgsbase.h b/arch/x86/include/asm/fsgsbase.h index bca4c743de77..d552646411a9 100644 --- a/arch/x86/include/asm/fsgsbase.h +++ b/arch/x86/include/asm/fsgsbase.h @@ -19,36 +19,65 @@ extern unsigned long x86_gsbase_read_task(struct task_struct *task); extern void x86_fsbase_write_task(struct task_struct *task, unsigned long fsbase); extern void x86_gsbase_write_task(struct task_struct *task, unsigned long gsbase); -/* Helper functions for reading/writing FS/GS base */ +/* Must be protected by X86_FEATURE_FSGSBASE check. */ -static inline unsigned long x86_fsbase_read_cpu(void) +static __always_inline unsigned long rdfsbase(void) { unsigned long fsbase; - rdmsrl(MSR_FS_BASE, fsbase); + asm volatile("rdfsbase %0" : "=r" (fsbase) :: "memory"); return fsbase; } -static inline unsigned long x86_gsbase_read_cpu_inactive(void) +static __always_inline unsigned long rdgsbase(void) { unsigned long gsbase; - rdmsrl(MSR_KERNEL_GS_BASE, gsbase); + asm volatile("rdgsbase %0" : "=r" (gsbase) :: "memory"); return gsbase; } -static inline void x86_fsbase_write_cpu(unsigned long fsbase) +static __always_inline void wrfsbase(unsigned long fsbase) { - wrmsrl(MSR_FS_BASE, fsbase); + asm volatile("wrfsbase %0" :: "r" (fsbase) : "memory"); } -static inline void x86_gsbase_write_cpu_inactive(unsigned long gsbase) +static __always_inline void wrgsbase(unsigned long gsbase) { - wrmsrl(MSR_KERNEL_GS_BASE, gsbase); + asm volatile("wrgsbase %0" :: "r" (gsbase) : "memory"); } +#include <asm/cpufeature.h> + +/* Helper functions for reading/writing FS/GS base */ + +static inline unsigned long x86_fsbase_read_cpu(void) +{ + unsigned long fsbase; + + if (static_cpu_has(X86_FEATURE_FSGSBASE)) + fsbase = rdfsbase(); + else + rdmsrl(MSR_FS_BASE, fsbase); + + return fsbase; +} + +static inline void x86_fsbase_write_cpu(unsigned long fsbase) +{ + if (static_cpu_has(X86_FEATURE_FSGSBASE)) + wrfsbase(fsbase); + else + wrmsrl(MSR_FS_BASE, fsbase); +} + +extern unsigned long x86_gsbase_read_cpu_inactive(void); +extern void x86_gsbase_write_cpu_inactive(unsigned long gsbase); +extern unsigned long x86_fsgsbase_read_task(struct task_struct *task, + unsigned short selector); + #endif /* CONFIG_X86_64 */ #endif /* __ASSEMBLY__ */ diff --git a/arch/x86/include/asm/inst.h b/arch/x86/include/asm/inst.h index 438ccd4f3cc4..bd7f02480ca1 100644 --- a/arch/x86/include/asm/inst.h +++ b/arch/x86/include/asm/inst.h @@ -143,6 +143,21 @@ .macro MODRM mod opd1 opd2 .byte \mod | (\opd1 & 7) | ((\opd2 & 7) << 3) .endm + +.macro RDPID opd + REG_TYPE rdpid_opd_type \opd + .if rdpid_opd_type == REG_TYPE_R64 + R64_NUM rdpid_opd \opd + .else + R32_NUM rdpid_opd \opd + .endif + .byte 0xf3 + .if rdpid_opd > 7 + PFX_REX rdpid_opd 0 + .endif + .byte 0x0f, 0xc7 + MODRM 0xc0 rdpid_opd 0x7 +.endm #endif #endif diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 68ba42fdd184..97143d87994c 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -457,10 +457,8 @@ static inline unsigned long cpu_kernelmode_gs_base(int cpu) DECLARE_PER_CPU(unsigned int, irq_count); extern asmlinkage void ignore_sysret(void); -#if IS_ENABLED(CONFIG_KVM) /* Save actual FS/GS selectors and bases to current->thread */ -void save_fsgs_for_kvm(void); -#endif +void current_save_fsgs(void); #else /* X86_64 */ #ifdef CONFIG_STACKPROTECTOR /* @@ -575,7 +573,7 @@ native_load_sp0(unsigned long sp0) this_cpu_write(cpu_tss_rw.x86_tss.sp0, sp0); } -static inline void native_swapgs(void) +static __always_inline void native_swapgs(void) { #ifdef CONFIG_X86_64 asm volatile("swapgs" ::: "memory"); diff --git a/arch/x86/include/uapi/asm/hwcap2.h b/arch/x86/include/uapi/asm/hwcap2.h index 8b2effe6efb8..5fdfcb47000f 100644 --- a/arch/x86/include/uapi/asm/hwcap2.h +++ b/arch/x86/include/uapi/asm/hwcap2.h @@ -5,4 +5,7 @@ /* MONITOR/MWAIT enabled in Ring 3 */ #define HWCAP2_RING3MWAIT (1 << 0) +/* Kernel allows FSGSBASE instructions available in Ring 3 */ +#define HWCAP2_FSGSBASE BIT(1) + #endif |