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Commit c4d6ee6e authored by Ingo Molnar's avatar Ingo Molnar
Browse files

x86/fpu: Remove failure paths from fpstate-alloc low level functions 



Now that we always allocate the FPU context as part of task_struct there's
no need for separate allocations - remove them and their primary failure
handling code.

( Note that there's still secondary error codes that have become superfluous,
  those will be removed in separate patches. )

Move the somewhat misplaced setup_xstate_comp() call to the core.

Reviewed-by: default avatarBorislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 7366ed77

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

+0 −4
Original line number Diff line number Diff line
@@ -558,10 +558,6 @@ static inline unsigned short get_fpu_mxcsr(struct task_struct *tsk) 
	}

}



extern void fpstate_cache_init(void);



extern int fpstate_alloc(struct fpu *fpu);

extern void fpstate_free(struct fpu *fpu);

extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu);



static inline unsigned long

arch/x86/kernel/fpu/core.c

+2 −49
Original line number Diff line number Diff line
@@ -225,34 +225,6 @@ void fpstate_init(struct fpu *fpu) 
}

EXPORT_SYMBOL_GPL(fpstate_init);



/*

 * FPU state allocation:

 */

static struct kmem_cache *task_xstate_cachep;



void fpstate_cache_init(void)

{

	task_xstate_cachep =

		kmem_cache_create("task_xstate", xstate_size,

				  __alignof__(union thread_xstate),

				  SLAB_PANIC | SLAB_NOTRACK, NULL);

	setup_xstate_comp();

}



int fpstate_alloc(struct fpu *fpu)

{

	/* The CPU requires the FPU state to be aligned to 16 byte boundaries: */

	WARN_ON((unsigned long)&fpu->state & 15);



	return 0;

}

EXPORT_SYMBOL_GPL(fpstate_alloc);



void fpstate_free(struct fpu *fpu)

{

}

EXPORT_SYMBOL_GPL(fpstate_free);



/*

 * Copy the current task's FPU state to a new task's FPU context.

 *
@@ -280,13 +252,9 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) 
	dst_fpu->fpregs_active = 0;

	dst_fpu->last_cpu = -1;



	if (src_fpu->fpstate_active) {

		int err = fpstate_alloc(dst_fpu);



		if (err)

			return err;

	if (src_fpu->fpstate_active)

		fpu_copy(dst_fpu, src_fpu);

	}



	return 0;

}
@@ -305,13 +273,6 @@ int fpstate_alloc_init(struct fpu *fpu) 
	if (WARN_ON_ONCE(fpu->fpstate_active))

		return -EINVAL;



	/*

	 * Memory allocation at the first usage of the FPU and other state.

	 */

	ret = fpstate_alloc(fpu);

	if (ret)

		return ret;



	fpstate_init(fpu);



	/* Safe to do for the current task: */
@@ -356,13 +317,6 @@ static int fpu__unlazy_stopped(struct fpu *child_fpu) 
		return 0;

	}



	/*

	 * Memory allocation at the first usage of the FPU and other state.

	 */

	ret = fpstate_alloc(child_fpu);

	if (ret)

		return ret;



	fpstate_init(child_fpu);



	/* Safe to do for stopped child tasks: */
@@ -423,7 +377,6 @@ void fpu__clear(struct task_struct *tsk) 
	if (!use_eager_fpu()) {

		/* FPU state will be reallocated lazily at the first use. */

		drop_fpu(fpu);

		fpstate_free(fpu);

	} else {

		if (!fpu->fpstate_active) {

			/* kthread execs. TODO: cleanup this horror. */

arch/x86/kernel/fpu/init.c

+1 −0
Original line number Diff line number Diff line
@@ -265,6 +265,7 @@ void fpu__init_system(struct cpuinfo_x86 *c) 
	fpu__init_system_generic();

	fpu__init_system_xstate_size_legacy();

	fpu__init_system_xstate();

	setup_xstate_comp();



	fpu__init_system_ctx_switch();

}

arch/x86/kernel/process.c

+0 −10
Original line number Diff line number Diff line
@@ -86,16 +86,6 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) 
	return fpu__copy(&dst->thread.fpu, &src->thread.fpu);

}



void arch_release_task_struct(struct task_struct *tsk)

{

	fpstate_free(&tsk->thread.fpu);

}



void arch_task_cache_init(void)

{

	fpstate_cache_init();

}



/*

 * Free current thread data structures etc..

 */

arch/x86/kvm/x86.c

+0 −11
Original line number Diff line number Diff line
@@ -7008,10 +7008,6 @@ int fx_init(struct kvm_vcpu *vcpu) 
{

	int err;



	err = fpstate_alloc(&vcpu->arch.guest_fpu);

	if (err)

		return err;



	fpstate_init(&vcpu->arch.guest_fpu);

	if (cpu_has_xsaves)

		vcpu->arch.guest_fpu.state.xsave.header.xcomp_bv =
@@ -7028,11 +7024,6 @@ int fx_init(struct kvm_vcpu *vcpu) 
}

EXPORT_SYMBOL_GPL(fx_init);



static void fx_free(struct kvm_vcpu *vcpu)

{

	fpstate_free(&vcpu->arch.guest_fpu);

}



void kvm_load_guest_fpu(struct kvm_vcpu *vcpu)

{

	if (vcpu->guest_fpu_loaded)
@@ -7070,7 +7061,6 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu) 
	kvmclock_reset(vcpu);



	free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);

	fx_free(vcpu);

	kvm_x86_ops->vcpu_free(vcpu);

}
@@ -7126,7 +7116,6 @@ void kvm_arch_vcpu_destroy(struct kvm_vcpu *vcpu) 
	kvm_mmu_unload(vcpu);

	vcpu_put(vcpu);



	fx_free(vcpu);

	kvm_x86_ops->vcpu_free(vcpu);

}