diff options
Diffstat (limited to 'arch/x86/include/asm/fpu/internal.h')
| -rw-r--r-- | arch/x86/include/asm/fpu/internal.h | 645 |
1 files changed, 0 insertions, 645 deletions
diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h deleted file mode 100644 index 44c48e34d799..000000000000 --- a/arch/x86/include/asm/fpu/internal.h +++ /dev/null @@ -1,645 +0,0 @@ -/* SPDX-License-Identifier: GPL-2.0 */ -/* - * Copyright (C) 1994 Linus Torvalds - * - * Pentium III FXSR, SSE support - * General FPU state handling cleanups - * Gareth Hughes <gareth@valinux.com>, May 2000 - * x86-64 work by Andi Kleen 2002 - */ - -#ifndef _ASM_X86_FPU_INTERNAL_H -#define _ASM_X86_FPU_INTERNAL_H - -#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> -#include <asm/fpu/xstate.h> -#include <asm/cpufeature.h> -#include <asm/trace/fpu.h> - -/* - * High level FPU state handling functions: - */ -extern void fpu__prepare_read(struct fpu *fpu); -extern void fpu__prepare_write(struct fpu *fpu); -extern void fpu__save(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 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); - -/* - * Boot time FPU initialization functions: - */ -extern void fpu__init_cpu(void); -extern void fpu__init_system_xstate(void); -extern void fpu__init_cpu_xstate(void); -extern void fpu__init_system(struct cpuinfo_x86 *c); -extern void fpu__init_check_bugs(void); -extern void fpu__resume_cpu(void); -extern u64 fpu__get_supported_xfeatures_mask(void); - -/* - * Debugging facility: - */ -#ifdef CONFIG_X86_DEBUG_FPU -# define WARN_ON_FPU(x) WARN_ON_ONCE(x) -#else -# define WARN_ON_FPU(x) ({ (void)(x); 0; }) -#endif - -/* - * FPU related CPU feature flag helper routines: - */ -static __always_inline __pure bool use_xsaveopt(void) -{ - return static_cpu_has(X86_FEATURE_XSAVEOPT); -} - -static __always_inline __pure bool use_xsave(void) -{ - return static_cpu_has(X86_FEATURE_XSAVE); -} - -static __always_inline __pure bool use_fxsr(void) -{ - return static_cpu_has(X86_FEATURE_FXSR); -} - -/* - * fpstate handling functions: - */ - -extern union fpregs_state init_fpstate; - -extern void fpstate_init(union fpregs_state *state); -#ifdef CONFIG_MATH_EMULATION -extern void fpstate_init_soft(struct swregs_state *soft); -#else -static inline void fpstate_init_soft(struct swregs_state *soft) {} -#endif - -static inline void fpstate_init_xstate(struct xregs_state *xsave) -{ - /* - * XRSTORS requires these bits set in xcomp_bv, or it will - * trigger #GP: - */ - xsave->header.xcomp_bv = XCOMP_BV_COMPACTED_FORMAT | xfeatures_mask; -} - -static inline void fpstate_init_fxstate(struct fxregs_state *fx) -{ - fx->cwd = 0x37f; - fx->mxcsr = MXCSR_DEFAULT; -} -extern void fpstate_sanitize_xstate(struct fpu *fpu); - -#define user_insn(insn, output, input...) \ -({ \ - int err; \ - \ - might_fault(); \ - \ - asm volatile(ASM_STAC "\n" \ - "1:" #insn "\n\t" \ - "2: " ASM_CLAC "\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_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" \ - _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_fprestore) \ - : output : input) - -static inline int copy_fregs_to_user(struct fregs_state __user *fx) -{ - return user_insn(fnsave %[fx]; fwait, [fx] "=m" (*fx), "m" (*fx)); -} - -static inline int copy_fxregs_to_user(struct fxregs_state __user *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx)); - else - return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx)); - -} - -static inline void copy_kernel_to_fxregs(struct fxregs_state *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - kernel_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else - 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)) - return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else - return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - -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)); -} - -static inline void copy_fxregs_to_kernel(struct fpu *fpu) -{ - if (IS_ENABLED(CONFIG_X86_32)) - asm volatile( "fxsave %[fx]" : [fx] "=m" (fpu->state.fxsave)); - else - asm volatile("fxsaveq %[fx]" : [fx] "=m" (fpu->state.fxsave)); -} - -/* These macros all use (%edi)/(%rdi) as the single memory argument. */ -#define XSAVE ".byte " REX_PREFIX "0x0f,0xae,0x27" -#define XSAVEOPT ".byte " REX_PREFIX "0x0f,0xae,0x37" -#define XSAVES ".byte " REX_PREFIX "0x0f,0xc7,0x2f" -#define XRSTOR ".byte " REX_PREFIX "0x0f,0xae,0x2f" -#define XRSTORS ".byte " REX_PREFIX "0x0f,0xc7,0x1f" - -#define XSTATE_OP(op, st, lmask, hmask, err) \ - asm volatile("1:" op "\n\t" \ - "xor %[err], %[err]\n" \ - "2:\n\t" \ - ".pushsection .fixup,\"ax\"\n\t" \ - "3: movl $-2,%[err]\n\t" \ - "jmp 2b\n\t" \ - ".popsection\n\t" \ - _ASM_EXTABLE(1b, 3b) \ - : [err] "=r" (err) \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * If XSAVES is enabled, it replaces XSAVEOPT because it supports a compact - * format and supervisor states in addition to modified optimization in - * XSAVEOPT. - * - * Otherwise, if XSAVEOPT is enabled, XSAVEOPT replaces XSAVE because XSAVEOPT - * supports modified optimization which is not supported by XSAVE. - * - * We use XSAVE as a fallback. - * - * The 661 label is defined in the ALTERNATIVE* macros as the address of the - * original instruction which gets replaced. We need to use it here as the - * address of the instruction where we might get an exception at. - */ -#define XSTATE_XSAVE(st, lmask, hmask, err) \ - asm volatile(ALTERNATIVE_2(XSAVE, \ - XSAVEOPT, X86_FEATURE_XSAVEOPT, \ - XSAVES, X86_FEATURE_XSAVES) \ - "\n" \ - "xor %[err], %[err]\n" \ - "3:\n" \ - ".pushsection .fixup,\"ax\"\n" \ - "4: movl $-2, %[err]\n" \ - "jmp 3b\n" \ - ".popsection\n" \ - _ASM_EXTABLE(661b, 4b) \ - : [err] "=r" (err) \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * Use XRSTORS to restore context if it is enabled. XRSTORS supports compact - * XSAVE area format. - */ -#define XSTATE_XRESTORE(st, lmask, hmask) \ - asm volatile(ALTERNATIVE(XRSTOR, \ - XRSTORS, X86_FEATURE_XSAVES) \ - "\n" \ - "3:\n" \ - _ASM_EXTABLE_HANDLE(661b, 3b, ex_handler_fprestore)\ - : \ - : "D" (st), "m" (*st), "a" (lmask), "d" (hmask) \ - : "memory") - -/* - * This function is called only during boot time when x86 caps are not set - * up and alternative can not be used yet. - */ -static inline void copy_xregs_to_kernel_booting(struct xregs_state *xstate) -{ - u64 mask = -1; - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - WARN_ON(system_state != SYSTEM_BOOTING); - - if (boot_cpu_has(X86_FEATURE_XSAVES)) - XSTATE_OP(XSAVES, xstate, lmask, hmask, err); - else - XSTATE_OP(XSAVE, xstate, lmask, hmask, err); - - /* We should never fault when copying to a kernel buffer: */ - WARN_ON_FPU(err); -} - -/* - * This function is called only during boot time when x86 caps are not set - * up and alternative can not be used yet. - */ -static inline void copy_kernel_to_xregs_booting(struct xregs_state *xstate) -{ - u64 mask = -1; - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - WARN_ON(system_state != SYSTEM_BOOTING); - - if (boot_cpu_has(X86_FEATURE_XSAVES)) - XSTATE_OP(XRSTORS, xstate, lmask, hmask, err); - else - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - - /* - * We should never fault when copying from a kernel buffer, and the FPU - * state we set at boot time should be valid. - */ - WARN_ON_FPU(err); -} - -/* - * Save processor xstate to xsave area. - */ -static inline void copy_xregs_to_kernel(struct xregs_state *xstate) -{ - u64 mask = -1; - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - WARN_ON_FPU(!alternatives_patched); - - XSTATE_XSAVE(xstate, lmask, hmask, err); - - /* We should never fault when copying to a kernel buffer: */ - WARN_ON_FPU(err); -} - -/* - * Restore processor xstate from xsave area. - */ -static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask) -{ - u32 lmask = mask; - u32 hmask = mask >> 32; - - XSTATE_XRESTORE(xstate, lmask, hmask); -} - -/* - * Save xstate to user space xsave area. - * - * We don't use modified optimization because xrstor/xrstors might track - * a different application. - * - * We don't use compacted format xsave area for - * backward compatibility for old applications which don't understand - * compacted format of xsave area. - */ -static inline int copy_xregs_to_user(struct xregs_state __user *buf) -{ - int err; - - /* - * Clear the xsave header first, so that reserved fields are - * initialized to zero. - */ - err = __clear_user(&buf->header, sizeof(buf->header)); - if (unlikely(err)) - return -EFAULT; - - stac(); - XSTATE_OP(XSAVE, buf, -1, -1, err); - clac(); - - return err; -} - -/* - * Restore xstate from user space xsave area. - */ -static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask) -{ - struct xregs_state *xstate = ((__force struct xregs_state *)buf); - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - stac(); - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - clac(); - - return err; -} - -/* - * 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. - * - * The legacy FNSAVE instruction cleared all FPU state - * unconditionally, so registers are essentially destroyed. - * Modern FPU state can be kept in registers, if there are - * no pending FP exceptions. - */ -static inline int copy_fpregs_to_fpstate(struct fpu *fpu) -{ - if (likely(use_xsave())) { - copy_xregs_to_kernel(&fpu->state.xsave); - - /* - * AVX512 state is tracked here because its use is - * known to slow the max clock speed of the core. - */ - if (fpu->state.xsave.header.xfeatures & XFEATURE_MASK_AVX512) - fpu->avx512_timestamp = jiffies; - return 1; - } - - if (likely(use_fxsr())) { - copy_fxregs_to_kernel(fpu); - return 1; - } - - /* - * Legacy FPU register saving, FNSAVE always clears FPU registers, - * so we have to mark them inactive: - */ - asm volatile("fnsave %[fp]; fwait" : [fp] "=m" (fpu->state.fsave)); - - return 0; -} - -static inline void __copy_kernel_to_fpregs(union fpregs_state *fpstate, u64 mask) -{ - if (use_xsave()) { - copy_kernel_to_xregs(&fpstate->xsave, mask); - } else { - if (use_fxsr()) - copy_kernel_to_fxregs(&fpstate->fxsave); - else - copy_kernel_to_fregs(&fpstate->fsave); - } -} - -static inline void copy_kernel_to_fpregs(union fpregs_state *fpstate) -{ - /* - * AMD K7/K8 CPUs don't save/restore FDP/FIP/FOP unless an exception is - * pending. Clear the x87 state here by setting it to fixed values. - * "m" is a random variable that should be in L1. - */ - if (unlikely(static_cpu_has_bug(X86_BUG_FXSAVE_LEAK))) { - asm volatile( - "fnclex\n\t" - "emms\n\t" - "fildl %P[addr]" /* set F?P to defined value */ - : : [addr] "m" (fpstate)); - } - - __copy_kernel_to_fpregs(fpstate, -1); -} - -extern int copy_fpstate_to_sigframe(void __user *buf, void __user *fp, int size); - -/* - * FPU context switch related helper methods: - */ - -DECLARE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx); - -/* - * The in-register FPU state for an FPU context on a CPU is assumed to be - * valid if the fpu->last_cpu matches the CPU, and the fpu_fpregs_owner_ctx - * matches the FPU. - * - * If the FPU register state is valid, the kernel can skip restoring the - * FPU state from memory. - * - * Any code that clobbers the FPU registers or updates the in-memory - * FPU state for a task MUST let the rest of the kernel know that the - * FPU registers are no longer valid for this task. - * - * Either one of these invalidation functions is enough. Invalidate - * a resource you control: CPU if using the CPU for something else - * (with preemption disabled), FPU for the current task, or a task that - * is prevented from running by the current task. - */ -static inline void __cpu_invalidate_fpregs_state(void) -{ - __this_cpu_write(fpu_fpregs_owner_ctx, NULL); -} - -static inline void __fpu_invalidate_fpregs_state(struct fpu *fpu) -{ - fpu->last_cpu = -1; -} - -static inline int fpregs_state_valid(struct fpu *fpu, unsigned int cpu) -{ - return fpu == this_cpu_read(fpu_fpregs_owner_ctx) && cpu == fpu->last_cpu; -} - -/* - * These generally need preemption protection to work, - * do try to avoid using these on their own: - */ -static inline void fpregs_deactivate(struct fpu *fpu) -{ - this_cpu_write(fpu_fpregs_owner_ctx, NULL); - trace_x86_fpu_regs_deactivated(fpu); -} - -static inline void fpregs_activate(struct fpu *fpu) -{ - this_cpu_write(fpu_fpregs_owner_ctx, fpu); - trace_x86_fpu_regs_activated(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->flags & PF_KTHREAD)) - 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: - * - * - switch_fpu_prepare() saves the old state. - * This is done within the context of the old process. - * - * - 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 - * PF_KTHREAD 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) && !(current->flags & PF_KTHREAD)) { - if (!copy_fpregs_to_fpstate(old_fpu)) - old_fpu->last_cpu = -1; - else - old_fpu->last_cpu = cpu; - - /* But leave fpu_fpregs_owner_ctx! */ - trace_x86_fpu_regs_deactivated(old_fpu); - } -} - -/* - * Misc helper functions: - */ - -/* - * 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) -{ - u32 pkru_val = init_pkru_value; - struct pkru_state *pk; - - if (!static_cpu_has(X86_FEATURE_FPU)) - return; - - set_thread_flag(TIF_NEED_FPU_LOAD); - - if (!cpu_feature_enabled(X86_FEATURE_OSPKE)) - return; - - /* - * 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); -} - -/* - * MXCSR and XCR definitions: - */ - -extern unsigned int mxcsr_feature_mask; - -#define XCR_XFEATURE_ENABLED_MASK 0x00000000 - -static inline u64 xgetbv(u32 index) -{ - u32 eax, edx; - - asm volatile(".byte 0x0f,0x01,0xd0" /* xgetbv */ - : "=a" (eax), "=d" (edx) - : "c" (index)); - return eax + ((u64)edx << 32); -} - -static inline void xsetbv(u32 index, u64 value) -{ - u32 eax = value; - u32 edx = value >> 32; - - asm volatile(".byte 0x0f,0x01,0xd1" /* xsetbv */ - : : "a" (eax), "d" (edx), "c" (index)); -} - -#endif /* _ASM_X86_FPU_INTERNAL_H */ |