arch/x86/include/asm/fpu/internal.h - third_party/kernel - Git at Google

 /* 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);

 /* Returns 0 or the negated trap number, which results in -EFAULT for #PF */
 #define user_insn(insn, output, input...)				\
 ({									\
 	int err;							\
 									\
 	might_fault();							\
 									\
 	asm volatile(ASM_STAC "\n"					\
 		     "1: " #insn "\n"					\
 		     "2: " ASM_CLAC "\n"				\
 		     ".section .fixup,\"ax\"\n"				\
 		     "3:  negl %%eax\n"					\
 		     "    jmp  2b\n"					\
 		     ".previous\n"					\
 		     _ASM_EXTABLE_FAULT(1b, 3b)				\
 		     : [err] "=a" (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));
 }

 static inline void fxsave(struct fxregs_state *fx)
 {
 	if (IS_ENABLED(CONFIG_X86_32))
 		asm volatile( "fxsave %[fx]" : [fx] "=m" (*fx));
 	else
 		asm volatile("fxsaveq %[fx]" : [fx] "=m" (*fx));
 }

 /* 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"

 /*
  * After this @err contains 0 on success or the negated trap number when
  * the operation raises an exception. For faults this results in -EFAULT.
  */
 #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: negl %%eax\n\t"				\
 		     "jmp 2b\n\t"					\
 		     ".popsection\n\t"					\
 		     _ASM_EXTABLE_FAULT(1b, 3b)				\
 		     : [err] "=a" (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_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 = &current->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->flags & PF_KTHREAD)) {
 		/*
 		 * If the PKRU bit in xsave.header.xfeatures is not set,
 		 * then the PKRU component was in init state, which means
 		 * XRSTOR will set PKRU to 0. If the bit is not set then
 		 * get_xsave_addr() will return NULL because the PKRU value
 		 * in memory is not valid. This means pkru_val has to be
 		 * set to 0 and not to init_pkru_value.
 		 */
 		pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
 		pkru_val = pk ? pk->pkru : 0;
 	}
 	__write_pkru(pkru_val);
 }

 /*
  * MXCSR and XCR definitions:
  */

 static inline void ldmxcsr(u32 mxcsr)
 {
 	asm volatile("ldmxcsr %0" :: "m" (mxcsr));
 }

 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 */
	/* 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);

	/* Returns 0 or the negated trap number, which results in -EFAULT for #PF */
	#define user_insn(insn, output, input...) \
	({ \
	int err; \
	\
	might_fault(); \
	\
	asm volatile(ASM_STAC "\n" \
	"1: " #insn "\n" \
	"2: " ASM_CLAC "\n" \
	".section .fixup,\"ax\"\n" \
	"3: negl %%eax\n" \
	" jmp 2b\n" \
	".previous\n" \
	_ASM_EXTABLE_FAULT(1b, 3b) \
	: [err] "=a" (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));
	}

	static inline void fxsave(struct fxregs_state *fx)
	{
	if (IS_ENABLED(CONFIG_X86_32))
	asm volatile( "fxsave %[fx]" : [fx] "=m" (*fx));
	else
	asm volatile("fxsaveq %[fx]" : [fx] "=m" (*fx));
	}

	/* 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"

	/*
	* After this @err contains 0 on success or the negated trap number when
	* the operation raises an exception. For faults this results in -EFAULT.
	*/
	#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: negl %%eax\n\t" \
	"jmp 2b\n\t" \
	".popsection\n\t" \
	_ASM_EXTABLE_FAULT(1b, 3b) \
	: [err] "=a" (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_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 = &current->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->flags & PF_KTHREAD)) {
	/*
	* If the PKRU bit in xsave.header.xfeatures is not set,
	* then the PKRU component was in init state, which means
	* XRSTOR will set PKRU to 0. If the bit is not set then
	* get_xsave_addr() will return NULL because the PKRU value
	* in memory is not valid. This means pkru_val has to be
	* set to 0 and not to init_pkru_value.
	*/
	pk = get_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU);
	pkru_val = pk ? pk->pkru : 0;
	}
	__write_pkru(pkru_val);
	}

	/*
	* MXCSR and XCR definitions:
	*/

	static inline void ldmxcsr(u32 mxcsr)
	{
	asm volatile("ldmxcsr %0" :: "m" (mxcsr));
	}

	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 */