x86/fpu: Convert task_struct::thread.fpu accesses to use x86_task_fpu()

This will make the removal of the task_struct::thread.fpu array
easier.

No change in functionality - code generated before and after this
commit is identical on x86-defconfig:

  kepler:~/tip> diff -up vmlinux.before.asm vmlinux.after.asm
  kepler:~/tip>

Signed-off-by: Ingo Molnar <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Brian Gerst <[email protected]>
Cc: Chang S. Bae <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

Author: Ingo Molnar

arch/x86/include/asm/fpu/sched.h

@@ -41,7 +41,7 @@ static inline void switch_fpu_prepare(struct task_struct *old, int cpu)
 {
 	if (cpu_feature_enabled(X86_FEATURE_FPU) &&
 	    !(old->flags & (PF_KTHREAD | PF_USER_WORKER))) {
-		struct fpu *old_fpu = &old->thread.fpu;
+		struct fpu *old_fpu = x86_task_fpu(old);
 
 		save_fpregs_to_fpstate(old_fpu);
 		/*

arch/x86/kernel/fpu/context.h

@@ -53,7 +53,7 @@ static inline void fpregs_activate(struct fpu *fpu)
 /* Internal helper for switch_fpu_return() and signal frame setup */
 static inline void fpregs_restore_userregs(void)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 	int cpu = smp_processor_id();
 
 	if (WARN_ON_ONCE(current->flags & (PF_KTHREAD | PF_USER_WORKER)))
@@ -67,7 +67,7 @@ static inline void fpregs_restore_userregs(void)
 		 * If PKRU is enabled, then the PKRU value is already
 		 * correct because it was either set in switch_to() or in
 		 * flush_thread(). So it is excluded because it might be
-		 * not up to date in current->thread.fpu.xsave state.
+		 * not up to date in current->thread.fpu->xsave state.
 		 *
 		 * XFD state is handled in restore_fpregs_from_fpstate().
 		 */

arch/x86/kernel/fpu/core.c

@@ -211,7 +211,7 @@ static void fpu_init_guest_permissions(struct fpu_guest *gfpu)
 		return;
 
 	spin_lock_irq(&current->sighand->siglock);
-	fpuperm = &current->group_leader->thread.fpu.guest_perm;
+	fpuperm = &x86_task_fpu(current->group_leader)->guest_perm;
 	perm = fpuperm->__state_perm;
 
 	/* First fpstate allocation locks down permissions. */
@@ -323,7 +323,7 @@ EXPORT_SYMBOL_GPL(fpu_update_guest_xfd);
  */
 void fpu_sync_guest_vmexit_xfd_state(void)
 {
-	struct fpstate *fps = current->thread.fpu.fpstate;
+	struct fpstate *fps = x86_task_fpu(current)->fpstate;
 
 	lockdep_assert_irqs_disabled();
 	if (fpu_state_size_dynamic()) {
@@ -337,7 +337,7 @@ EXPORT_SYMBOL_GPL(fpu_sync_guest_vmexit_xfd_state);
 int fpu_swap_kvm_fpstate(struct fpu_guest *guest_fpu, bool enter_guest)
 {
 	struct fpstate *guest_fps = guest_fpu->fpstate;
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 	struct fpstate *cur_fps = fpu->fpstate;
 
 	fpregs_lock();
@@ -438,7 +438,7 @@ void kernel_fpu_begin_mask(unsigned int kfpu_mask)
 	if (!(current->flags & (PF_KTHREAD | PF_USER_WORKER)) &&
 	    !test_thread_flag(TIF_NEED_FPU_LOAD)) {
 		set_thread_flag(TIF_NEED_FPU_LOAD);
-		save_fpregs_to_fpstate(&current->thread.fpu);
+		save_fpregs_to_fpstate(x86_task_fpu(current));
 	}
 	__cpu_invalidate_fpregs_state();
 
@@ -467,7 +467,7 @@ EXPORT_SYMBOL_GPL(kernel_fpu_end);
  */
 void fpu_sync_fpstate(struct fpu *fpu)
 {
-	WARN_ON_FPU(fpu != &current->thread.fpu);
+	WARN_ON_FPU(fpu != x86_task_fpu(current));
 
 	fpregs_lock();
 	trace_x86_fpu_before_save(fpu);
@@ -552,7 +552,7 @@ void fpstate_reset(struct fpu *fpu)
 static inline void fpu_inherit_perms(struct fpu *dst_fpu)
 {
 	if (fpu_state_size_dynamic()) {
-		struct fpu *src_fpu = &current->group_leader->thread.fpu;
+		struct fpu *src_fpu = x86_task_fpu(current->group_leader);
 
 		spin_lock_irq(&current->sighand->siglock);
 		/* Fork also inherits the permissions of the parent */
@@ -572,7 +572,7 @@ static int update_fpu_shstk(struct task_struct *dst, unsigned long ssp)
 	if (!ssp)
 		return 0;
 
-	xstate = get_xsave_addr(&dst->thread.fpu.fpstate->regs.xsave,
+	xstate = get_xsave_addr(&x86_task_fpu(dst)->fpstate->regs.xsave,
 				XFEATURE_CET_USER);
 
 	/*
@@ -593,8 +593,8 @@ static int update_fpu_shstk(struct task_struct *dst, unsigned long ssp)
 int fpu_clone(struct task_struct *dst, unsigned long clone_flags, bool minimal,
 	      unsigned long ssp)
 {
-	struct fpu *src_fpu = &current->thread.fpu;
-	struct fpu *dst_fpu = &dst->thread.fpu;
+	struct fpu *src_fpu = x86_task_fpu(current);
+	struct fpu *dst_fpu = x86_task_fpu(dst);
 
 	/* The new task's FPU state cannot be valid in the hardware. */
 	dst_fpu->last_cpu = -1;
@@ -686,7 +686,7 @@ void fpu__drop(struct fpu *fpu)
 {
 	preempt_disable();
 
-	if (fpu == &current->thread.fpu) {
+	if (fpu == x86_task_fpu(current)) {
 		/* Ignore delayed exceptions from user space */
 		asm volatile("1: fwait\n"
 			     "2:\n"
@@ -720,7 +720,7 @@ static inline void restore_fpregs_from_init_fpstate(u64 features_mask)
  */
 static void fpu_reset_fpregs(void)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 
 	fpregs_lock();
 	__fpu_invalidate_fpregs_state(fpu);
@@ -749,7 +749,7 @@ static void fpu_reset_fpregs(void)
  */
 void fpu__clear_user_states(struct fpu *fpu)
 {
-	WARN_ON_FPU(fpu != &current->thread.fpu);
+	WARN_ON_FPU(fpu != x86_task_fpu(current));
 
 	fpregs_lock();
 	if (!cpu_feature_enabled(X86_FEATURE_FPU)) {
@@ -782,7 +782,7 @@ void fpu__clear_user_states(struct fpu *fpu)
 
 void fpu_flush_thread(void)
 {
-	fpstate_reset(&current->thread.fpu);
+	fpstate_reset(x86_task_fpu(current));
 	fpu_reset_fpregs();
 }
 /*
@@ -823,7 +823,7 @@ void fpregs_lock_and_load(void)
  */
 void fpregs_assert_state_consistent(void)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 
 	if (test_thread_flag(TIF_NEED_FPU_LOAD))
 		return;
@@ -835,7 +835,7 @@ EXPORT_SYMBOL_GPL(fpregs_assert_state_consistent);
 
 void fpregs_mark_activate(void)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 
 	fpregs_activate(fpu);
 	fpu->last_cpu = smp_processor_id();

arch/x86/kernel/fpu/init.c

@@ -38,7 +38,7 @@ static void fpu__init_cpu_generic(void)
 	/* Flush out any pending x87 state: */
 #ifdef CONFIG_MATH_EMULATION
 	if (!boot_cpu_has(X86_FEATURE_FPU))
-		fpstate_init_soft(&current->thread.fpu.fpstate->regs.soft);
+		fpstate_init_soft(&x86_task_fpu(current)->fpstate->regs.soft);
 	else
 #endif
 		asm volatile ("fninit");
@@ -154,7 +154,7 @@ static void __init fpu__init_task_struct_size(void)
 	 * Subtract off the static size of the register state.
 	 * It potentially has a bunch of padding.
 	 */
-	task_size -= sizeof(current->thread.fpu.__fpstate.regs);
+	task_size -= sizeof(union fpregs_state);
 
 	/*
 	 * Add back the dynamically-calculated register state
@@ -204,7 +204,7 @@ static void __init fpu__init_system_xstate_size_legacy(void)
 	fpu_kernel_cfg.default_size = size;
 	fpu_user_cfg.max_size = size;
 	fpu_user_cfg.default_size = size;
-	fpstate_reset(&current->thread.fpu);
+	fpstate_reset(x86_task_fpu(current));
 }
 
 /*
@@ -213,7 +213,7 @@ static void __init fpu__init_system_xstate_size_legacy(void)
  */
 void __init fpu__init_system(void)
 {
-	fpstate_reset(&current->thread.fpu);
+	fpstate_reset(x86_task_fpu(current));
 	fpu__init_system_early_generic();
 
 	/*

arch/x86/kernel/fpu/regset.c

@@ -45,7 +45,7 @@ int regset_xregset_fpregs_active(struct task_struct *target, const struct user_r
  */
 static void sync_fpstate(struct fpu *fpu)
 {
-	if (fpu == &current->thread.fpu)
+	if (fpu == x86_task_fpu(current))
 		fpu_sync_fpstate(fpu);
 }
 
@@ -63,15 +63,15 @@ static void fpu_force_restore(struct fpu *fpu)
 	 * Only stopped child tasks can be used to modify the FPU
 	 * state in the fpstate buffer:
 	 */
-	WARN_ON_FPU(fpu == &current->thread.fpu);
+	WARN_ON_FPU(fpu == x86_task_fpu(current));
 
 	__fpu_invalidate_fpregs_state(fpu);
 }
 
 int xfpregs_get(struct task_struct *target, const struct user_regset *regset,
 		struct membuf to)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 
 	if (!cpu_feature_enabled(X86_FEATURE_FXSR))
 		return -ENODEV;
@@ -91,7 +91,7 @@ int xfpregs_set(struct task_struct *target, const struct user_regset *regset,
 		unsigned int pos, unsigned int count,
 		const void *kbuf, const void __user *ubuf)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct fxregs_state newstate;
 	int ret;
 
@@ -133,7 +133,7 @@ int xstateregs_get(struct task_struct *target, const struct user_regset *regset,
 	if (!cpu_feature_enabled(X86_FEATURE_XSAVE))
 		return -ENODEV;
 
-	sync_fpstate(&target->thread.fpu);
+	sync_fpstate(x86_task_fpu(target));
 
 	copy_xstate_to_uabi_buf(to, target, XSTATE_COPY_XSAVE);
 	return 0;
@@ -143,7 +143,7 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 		  unsigned int pos, unsigned int count,
 		  const void *kbuf, const void __user *ubuf)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct xregs_state *tmpbuf = NULL;
 	int ret;
 
@@ -187,7 +187,7 @@ int ssp_active(struct task_struct *target, const struct user_regset *regset)
 int ssp_get(struct task_struct *target, const struct user_regset *regset,
 	    struct membuf to)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct cet_user_state *cetregs;
 
 	if (!cpu_feature_enabled(X86_FEATURE_USER_SHSTK) ||
@@ -214,7 +214,7 @@ int ssp_set(struct task_struct *target, const struct user_regset *regset,
 	    unsigned int pos, unsigned int count,
 	    const void *kbuf, const void __user *ubuf)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct xregs_state *xsave = &fpu->fpstate->regs.xsave;
 	struct cet_user_state *cetregs;
 	unsigned long user_ssp;
@@ -368,7 +368,7 @@ static void __convert_from_fxsr(struct user_i387_ia32_struct *env,
 void
 convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk)
 {
-	__convert_from_fxsr(env, tsk, &tsk->thread.fpu.fpstate->regs.fxsave);
+	__convert_from_fxsr(env, tsk, &x86_task_fpu(tsk)->fpstate->regs.fxsave);
 }
 
 void convert_to_fxsr(struct fxregs_state *fxsave,
@@ -401,7 +401,7 @@ void convert_to_fxsr(struct fxregs_state *fxsave,
 int fpregs_get(struct task_struct *target, const struct user_regset *regset,
 	       struct membuf to)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct user_i387_ia32_struct env;
 	struct fxregs_state fxsave, *fx;
 
@@ -433,7 +433,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset,
 	       unsigned int pos, unsigned int count,
 	       const void *kbuf, const void __user *ubuf)
 {
-	struct fpu *fpu = &target->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(target);
 	struct user_i387_ia32_struct env;
 	int ret;
 

arch/x86/kernel/fpu/signal.c

@@ -43,13 +43,13 @@ static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
 	 * fpstate layout with out copying the extended state information
 	 * in the memory layout.
 	 */
-	if (__get_user(magic2, (__u32 __user *)(fpstate + current->thread.fpu.fpstate->user_size)))
+	if (__get_user(magic2, (__u32 __user *)(fpstate + x86_task_fpu(current)->fpstate->user_size)))
 		return false;
 
 	if (likely(magic2 == FP_XSTATE_MAGIC2))
 		return true;
 setfx:
-	trace_x86_fpu_xstate_check_failed(&current->thread.fpu);
+	trace_x86_fpu_xstate_check_failed(x86_task_fpu(current));
 
 	/* Set the parameters for fx only state */
 	fx_sw->magic1 = 0;
@@ -64,13 +64,13 @@ static inline bool check_xstate_in_sigframe(struct fxregs_state __user *fxbuf,
 static inline bool save_fsave_header(struct task_struct *tsk, void __user *buf)
 {
 	if (use_fxsr()) {
-		struct xregs_state *xsave = &tsk->thread.fpu.fpstate->regs.xsave;
+		struct xregs_state *xsave = &x86_task_fpu(tsk)->fpstate->regs.xsave;
 		struct user_i387_ia32_struct env;
 		struct _fpstate_32 __user *fp = buf;
 
 		fpregs_lock();
 		if (!test_thread_flag(TIF_NEED_FPU_LOAD))
-			fxsave(&tsk->thread.fpu.fpstate->regs.fxsave);
+			fxsave(&x86_task_fpu(tsk)->fpstate->regs.fxsave);
 		fpregs_unlock();
 
 		convert_from_fxsr(&env, tsk);
@@ -184,7 +184,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf, u32 pk
 bool copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size, u32 pkru)
 {
 	struct task_struct *tsk = current;
-	struct fpstate *fpstate = tsk->thread.fpu.fpstate;
+	struct fpstate *fpstate = x86_task_fpu(tsk)->fpstate;
 	bool ia32_fxstate = (buf != buf_fx);
 	int ret;
 
@@ -272,7 +272,7 @@ static int __restore_fpregs_from_user(void __user *buf, u64 ufeatures,
  */
 static bool restore_fpregs_from_user(void __user *buf, u64 xrestore, bool fx_only)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 	int ret;
 
 	/* Restore enabled features only. */
@@ -332,7 +332,7 @@ static bool __fpu_restore_sig(void __user *buf, void __user *buf_fx,
 			      bool ia32_fxstate)
 {
 	struct task_struct *tsk = current;
-	struct fpu *fpu = &tsk->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(tsk);
 	struct user_i387_ia32_struct env;
 	bool success, fx_only = false;
 	union fpregs_state *fpregs;
@@ -452,7 +452,7 @@ static inline unsigned int xstate_sigframe_size(struct fpstate *fpstate)
  */
 bool fpu__restore_sig(void __user *buf, int ia32_frame)
 {
-	struct fpu *fpu = &current->thread.fpu;
+	struct fpu *fpu = x86_task_fpu(current);
 	void __user *buf_fx = buf;
 	bool ia32_fxstate = false;
 	bool success = false;
@@ -499,7 +499,7 @@ unsigned long
 fpu__alloc_mathframe(unsigned long sp, int ia32_frame,
 		     unsigned long *buf_fx, unsigned long *size)
 {
-	unsigned long frame_size = xstate_sigframe_size(current->thread.fpu.fpstate);
+	unsigned long frame_size = xstate_sigframe_size(x86_task_fpu(current)->fpstate);
 
 	*buf_fx = sp = round_down(sp - frame_size, 64);
 	if (ia32_frame && use_fxsr()) {