diff options
Diffstat (limited to 'arch/x86/include')
| -rw-r--r-- | arch/x86/include/asm/fpu/api.h | 31 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 133 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/signal.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/types.h | 9 | ||||
| -rw-r--r-- | arch/x86/include/asm/fpu/xstate.h | 8 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable.h | 29 | ||||
| -rw-r--r-- | arch/x86/include/asm/special_insns.h | 19 | ||||
| -rw-r--r-- | arch/x86/include/asm/thread_info.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/trace/fpu.h | 13 |
9 files changed, 185 insertions, 61 deletions
diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index b56d504af654..b774c52e5411 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -10,6 +10,7 @@ #ifndef _ASM_X86_FPU_API_H #define _ASM_X86_FPU_API_H +#include <linux/bottom_half.h> /* * Use kernel_fpu_begin/end() if you intend to use FPU in kernel context. It @@ -21,6 +22,36 @@ extern void kernel_fpu_begin(void); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); +extern void fpregs_mark_activate(void); + +/* + * Use fpregs_lock() while editing CPU's FPU registers or fpu->state. + * A context switch will (and softirq might) save CPU's FPU registers to + * fpu->state and set TIF_NEED_FPU_LOAD leaving CPU's FPU registers in + * a random state. + */ +static inline void fpregs_lock(void) +{ + preempt_disable(); + local_bh_disable(); +} + +static inline void fpregs_unlock(void) +{ + local_bh_enable(); + preempt_enable(); +} + +#ifdef CONFIG_X86_DEBUG_FPU +extern void fpregs_assert_state_consistent(void); +#else +static inline void fpregs_assert_state_consistent(void) { } +#endif + +/* + * Load the task FPU state before returning to userspace. + */ +extern void switch_fpu_return(void); /* * Query the presence of one or more xfeatures. Works on any legacy CPU as well. diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 745a19d34f23..9e27fa05a7ae 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -14,6 +14,7 @@ #include <linux/compat.h> #include <linux/sched.h> #include <linux/slab.h> +#include <linux/mm.h> #include <asm/user.h> #include <asm/fpu/api.h> @@ -24,14 +25,12 @@ /* * High level FPU state handling functions: */ -extern void fpu__initialize(struct fpu *fpu); extern void fpu__prepare_read(struct fpu *fpu); extern void fpu__prepare_write(struct fpu *fpu); extern void fpu__save(struct fpu *fpu); -extern void fpu__restore(struct fpu *fpu); extern int fpu__restore_sig(void __user *buf, int ia32_frame); extern void fpu__drop(struct fpu *fpu); -extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu); +extern int fpu__copy(struct task_struct *dst, struct task_struct *src); extern void fpu__clear(struct fpu *fpu); extern int fpu__exception_code(struct fpu *fpu, int trap_nr); extern int dump_fpu(struct pt_regs *ptregs, struct user_i387_struct *fpstate); @@ -122,6 +121,21 @@ extern void fpstate_sanitize_xstate(struct fpu *fpu); err; \ }) +#define kernel_insn_err(insn, output, input...) \ +({ \ + int err; \ + asm volatile("1:" #insn "\n\t" \ + "2:\n" \ + ".section .fixup,\"ax\"\n" \ + "3: movl $-1,%[err]\n" \ + " jmp 2b\n" \ + ".previous\n" \ + _ASM_EXTABLE(1b, 3b) \ + : [err] "=r" (err), output \ + : "0"(0), input); \ + err; \ +}) + #define kernel_insn(insn, output, input...) \ asm volatile("1:" #insn "\n\t" \ "2:\n" \ @@ -150,6 +164,14 @@ static inline void copy_kernel_to_fxregs(struct fxregs_state *fx) kernel_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); } +static inline int copy_kernel_to_fxregs_err(struct fxregs_state *fx) +{ + if (IS_ENABLED(CONFIG_X86_32)) + return kernel_insn_err(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); + else + return kernel_insn_err(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + static inline int copy_user_to_fxregs(struct fxregs_state __user *fx) { if (IS_ENABLED(CONFIG_X86_32)) @@ -163,6 +185,11 @@ static inline void copy_kernel_to_fregs(struct fregs_state *fx) kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); } +static inline int copy_kernel_to_fregs_err(struct fregs_state *fx) +{ + return kernel_insn_err(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); +} + static inline int copy_user_to_fregs(struct fregs_state __user *fx) { return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); @@ -363,6 +390,21 @@ static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask) } /* + * Restore xstate from kernel space xsave area, return an error code instead of + * an exception. + */ +static inline int copy_kernel_to_xregs_err(struct xregs_state *xstate, u64 mask) +{ + u32 lmask = mask; + u32 hmask = mask >> 32; + int err; + + XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); + + return err; +} + +/* * These must be called with preempt disabled. Returns * 'true' if the FPU state is still intact and we can * keep registers active. @@ -487,6 +529,25 @@ static inline void fpregs_activate(struct fpu *fpu) } /* + * Internal helper, do not use directly. Use switch_fpu_return() instead. + */ +static inline void __fpregs_load_activate(void) +{ + struct fpu *fpu = ¤t->thread.fpu; + int cpu = smp_processor_id(); + + if (WARN_ON_ONCE(current->mm == NULL)) + return; + + if (!fpregs_state_valid(fpu, cpu)) { + copy_kernel_to_fpregs(&fpu->state); + fpregs_activate(fpu); + fpu->last_cpu = cpu; + } + clear_thread_flag(TIF_NEED_FPU_LOAD); +} + +/* * FPU state switching for scheduling. * * This is a two-stage process: @@ -494,12 +555,23 @@ static inline void fpregs_activate(struct fpu *fpu) * - switch_fpu_prepare() saves the old state. * This is done within the context of the old process. * - * - switch_fpu_finish() restores the new state as - * necessary. + * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state + * will get loaded on return to userspace, or when the kernel needs it. + * + * If TIF_NEED_FPU_LOAD is cleared then the CPU's FPU registers + * are saved in the current thread's FPU register state. + * + * If TIF_NEED_FPU_LOAD is set then CPU's FPU registers may not + * hold current()'s FPU registers. It is required to load the + * registers before returning to userland or using the content + * otherwise. + * + * The FPU context is only stored/restored for a user task and + * ->mm is used to distinguish between kernel and user threads. */ static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU) && old_fpu->initialized) { + if (static_cpu_has(X86_FEATURE_FPU) && current->mm) { if (!copy_fpregs_to_fpstate(old_fpu)) old_fpu->last_cpu = -1; else @@ -507,8 +579,7 @@ static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) /* But leave fpu_fpregs_owner_ctx! */ trace_x86_fpu_regs_deactivated(old_fpu); - } else - old_fpu->last_cpu = -1; + } } /* @@ -516,36 +587,32 @@ static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ /* - * Set up the userspace FPU context for the new task, if the task - * has used the FPU. + * Load PKRU from the FPU context if available. Delay loading of the + * complete FPU state until the return to userland. */ -static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) +static inline void switch_fpu_finish(struct fpu *new_fpu) { - bool preload = static_cpu_has(X86_FEATURE_FPU) && - new_fpu->initialized; + u32 pkru_val = init_pkru_value; + struct pkru_state *pk; - if (preload) { - if (!fpregs_state_valid(new_fpu, cpu)) - copy_kernel_to_fpregs(&new_fpu->state); - fpregs_activate(new_fpu); - } -} + if (!static_cpu_has(X86_FEATURE_FPU)) + return; -/* - * Needs to be preemption-safe. - * - * NOTE! user_fpu_begin() must be used only immediately before restoring - * the save state. It does not do any saving/restoring on its own. In - * lazy FPU mode, it is just an optimization to avoid a #NM exception, - * the task can lose the FPU right after preempt_enable(). - */ -static inline void user_fpu_begin(void) -{ - struct fpu *fpu = ¤t->thread.fpu; + set_thread_flag(TIF_NEED_FPU_LOAD); + + if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) + return; - preempt_disable(); - fpregs_activate(fpu); - preempt_enable(); + /* + * PKRU state is switched eagerly because it needs to be valid before we + * return to userland e.g. for a copy_to_user() operation. + */ + if (current->mm) { + pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU); + if (pk) + pkru_val = pk->pkru; + } + __write_pkru(pkru_val); } /* diff --git a/arch/x86/include/asm/fpu/signal.h b/arch/x86/include/asm/fpu/signal.h index 44bbc39a57b3..7fb516b6893a 100644 --- a/arch/x86/include/asm/fpu/signal.h +++ b/arch/x86/include/asm/fpu/signal.h @@ -22,7 +22,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, extern void convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk); -extern void convert_to_fxsr(struct task_struct *tsk, +extern void convert_to_fxsr(struct fxregs_state *fxsave, const struct user_i387_ia32_struct *env); unsigned long diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 2e32e178e064..f098f6cab94b 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -294,15 +294,6 @@ struct fpu { unsigned int last_cpu; /* - * @initialized: - * - * This flag indicates whether this context is initialized: if the task - * is not running then we can restore from this context, if the task - * is running then we should save into this context. - */ - unsigned char initialized; - - /* * @avx512_timestamp: * * Records the timestamp of AVX512 use during last context switch. diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 48581988d78c..7e42b285c856 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -2,9 +2,11 @@ #ifndef __ASM_X86_XSAVE_H #define __ASM_X86_XSAVE_H +#include <linux/uaccess.h> #include <linux/types.h> + #include <asm/processor.h> -#include <linux/uaccess.h> +#include <asm/user.h> /* Bit 63 of XCR0 is reserved for future expansion */ #define XFEATURE_MASK_EXTEND (~(XFEATURE_MASK_FPSSE | (1ULL << 63))) @@ -46,8 +48,8 @@ extern void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask); void fpu__xstate_clear_all_cpu_caps(void); -void *get_xsave_addr(struct xregs_state *xsave, int xstate); -const void *get_xsave_field_ptr(int xstate_field); +void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); +const void *get_xsave_field_ptr(int xfeature_nr); int using_compacted_format(void); int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 3a221942f805..5e0509b41986 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -23,6 +23,8 @@ #ifndef __ASSEMBLY__ #include <asm/x86_init.h> +#include <asm/fpu/xstate.h> +#include <asm/fpu/api.h> extern pgd_t early_top_pgt[PTRS_PER_PGD]; int __init __early_make_pgtable(unsigned long address, pmdval_t pmd); @@ -127,14 +129,29 @@ static inline int pte_dirty(pte_t pte) static inline u32 read_pkru(void) { if (boot_cpu_has(X86_FEATURE_OSPKE)) - return __read_pkru(); + return rdpkru(); return 0; } static inline void write_pkru(u32 pkru) { - if (boot_cpu_has(X86_FEATURE_OSPKE)) - __write_pkru(pkru); + struct pkru_state *pk; + + if (!boot_cpu_has(X86_FEATURE_OSPKE)) + return; + + pk = get_xsave_addr(¤t->thread.fpu.state.xsave, XFEATURE_PKRU); + + /* + * The PKRU value in xstate needs to be in sync with the value that is + * written to the CPU. The FPU restore on return to userland would + * otherwise load the previous value again. + */ + fpregs_lock(); + if (pk) + pk->pkru = pkru; + __write_pkru(pkru); + fpregs_unlock(); } static inline int pte_young(pte_t pte) @@ -1358,6 +1375,12 @@ static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd) #define PKRU_WD_BIT 0x2 #define PKRU_BITS_PER_PKEY 2 +#ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS +extern u32 init_pkru_value; +#else +#define init_pkru_value 0 +#endif + static inline bool __pkru_allows_read(u32 pkru, u16 pkey) { int pkru_pkey_bits = pkey * PKRU_BITS_PER_PKEY; diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 43c029cdc3fe..0a3c4cab39db 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -92,7 +92,7 @@ static inline void native_write_cr8(unsigned long val) #endif #ifdef CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS -static inline u32 __read_pkru(void) +static inline u32 rdpkru(void) { u32 ecx = 0; u32 edx, pkru; @@ -107,7 +107,7 @@ static inline u32 __read_pkru(void) return pkru; } -static inline void __write_pkru(u32 pkru) +static inline void wrpkru(u32 pkru) { u32 ecx = 0, edx = 0; @@ -118,8 +118,21 @@ static inline void __write_pkru(u32 pkru) asm volatile(".byte 0x0f,0x01,0xef\n\t" : : "a" (pkru), "c"(ecx), "d"(edx)); } + +static inline void __write_pkru(u32 pkru) +{ + /* + * WRPKRU is relatively expensive compared to RDPKRU. + * Avoid WRPKRU when it would not change the value. + */ + if (pkru == rdpkru()) + return; + + wrpkru(pkru); +} + #else -static inline u32 __read_pkru(void) +static inline u32 rdpkru(void) { return 0; } diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index e0eccbcb8447..f9453536f9bb 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -88,6 +88,7 @@ struct thread_info { #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ #define TIF_UPROBE 12 /* breakpointed or singlestepping */ #define TIF_PATCH_PENDING 13 /* pending live patching update */ +#define TIF_NEED_FPU_LOAD 14 /* load FPU on return to userspace */ #define TIF_NOCPUID 15 /* CPUID is not accessible in userland */ #define TIF_NOTSC 16 /* TSC is not accessible in userland */ #define TIF_IA32 17 /* IA32 compatibility process */ @@ -117,6 +118,7 @@ struct thread_info { #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) #define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) +#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD) #define _TIF_NOCPUID (1 << TIF_NOCPUID) #define _TIF_NOTSC (1 << TIF_NOTSC) #define _TIF_IA32 (1 << TIF_IA32) diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h index 069c04be1507..879b77792f94 100644 --- a/arch/x86/include/asm/trace/fpu.h +++ b/arch/x86/include/asm/trace/fpu.h @@ -13,22 +13,22 @@ DECLARE_EVENT_CLASS(x86_fpu, TP_STRUCT__entry( __field(struct fpu *, fpu) - __field(bool, initialized) + __field(bool, load_fpu) __field(u64, xfeatures) __field(u64, xcomp_bv) ), TP_fast_assign( __entry->fpu = fpu; - __entry->initialized = fpu->initialized; + __entry->load_fpu = test_thread_flag(TIF_NEED_FPU_LOAD); if (boot_cpu_has(X86_FEATURE_OSXSAVE)) { __entry->xfeatures = fpu->state.xsave.header.xfeatures; __entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv; } ), - TP_printk("x86/fpu: %p initialized: %d xfeatures: %llx xcomp_bv: %llx", + TP_printk("x86/fpu: %p load: %d xfeatures: %llx xcomp_bv: %llx", __entry->fpu, - __entry->initialized, + __entry->load_fpu, __entry->xfeatures, __entry->xcomp_bv ) @@ -64,11 +64,6 @@ DEFINE_EVENT(x86_fpu, x86_fpu_regs_deactivated, TP_ARGS(fpu) ); -DEFINE_EVENT(x86_fpu, x86_fpu_activate_state, - TP_PROTO(struct fpu *fpu), - TP_ARGS(fpu) -); - DEFINE_EVENT(x86_fpu, x86_fpu_init_state, TP_PROTO(struct fpu *fpu), TP_ARGS(fpu) |