x86, fpu: lazy allocation of FPU area - v5 (aa283f49) · Commits · e / devices / android_kernel_fairphone_FP5

arch/x86/kernel/i387.c

+30 −8

Original line number	Original line	Diff line number	Diff line
	@@ -8,7 +8,6 @@
	#include <linux/module.h>		#include <linux/module.h>
	#include <linux/regset.h>		#include <linux/regset.h>
	#include <linux/sched.h>		#include <linux/sched.h>
	#include <linux/bootmem.h>

	#include <asm/sigcontext.h>		#include <asm/sigcontext.h>
	#include <asm/processor.h>		#include <asm/processor.h>
	@@ -63,7 +62,6 @@ void __init init_thread_xstate(void)
	else		else
	xstate_size = sizeof(struct i387_fsave_struct);		xstate_size = sizeof(struct i387_fsave_struct);
	#endif		#endif
	init_task.thread.xstate = alloc_bootmem(xstate_size);
	}		}

	#ifdef CONFIG_X86_64		#ifdef CONFIG_X86_64
	@@ -93,12 +91,22 @@ void __cpuinit fpu_init(void)
	* value at reset if we support XMM instructions and then		* value at reset if we support XMM instructions and then
	* remeber the current task has used the FPU.		* remeber the current task has used the FPU.
	*/		*/
	void init_fpu(struct task_struct *tsk)		int init_fpu(struct task_struct *tsk)
	{		{
	if (tsk_used_math(tsk)) {		if (tsk_used_math(tsk)) {
	if (tsk == current)		if (tsk == current)
	unlazy_fpu(tsk);		unlazy_fpu(tsk);
	return;		return 0;
			}

			/*
			* Memory allocation at the first usage of the FPU and other state.
			*/
			if (!tsk->thread.xstate) {
			tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
			GFP_KERNEL);
			if (!tsk->thread.xstate)
			return -ENOMEM;
	}		}

	if (cpu_has_fxsr) {		if (cpu_has_fxsr) {
	@@ -120,6 +128,7 @@ void init_fpu(struct task_struct *tsk)
	* Only the device not available exception or ptrace can call init_fpu.		* Only the device not available exception or ptrace can call init_fpu.
	*/		*/
	set_stopped_child_used_math(tsk);		set_stopped_child_used_math(tsk);
			return 0;
	}		}

	int fpregs_active(struct task_struct target, const struct user_regset regset)		int fpregs_active(struct task_struct target, const struct user_regset regset)
	@@ -136,10 +145,14 @@ int xfpregs_get(struct task_struct target, const struct user_regset regset,
	unsigned int pos, unsigned int count,		unsigned int pos, unsigned int count,
	void kbuf, void __user ubuf)		void kbuf, void __user ubuf)
	{		{
			int ret;

	if (!cpu_has_fxsr)		if (!cpu_has_fxsr)
	return -ENODEV;		return -ENODEV;

	init_fpu(target);		ret = init_fpu(target);
			if (ret)
			return ret;

	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,		return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
	&target->thread.xstate->fxsave, 0, -1);		&target->thread.xstate->fxsave, 0, -1);
	@@ -154,7 +167,10 @@ int xfpregs_set(struct task_struct target, const struct user_regset regset,
	if (!cpu_has_fxsr)		if (!cpu_has_fxsr)
	return -ENODEV;		return -ENODEV;

	init_fpu(target);		ret = init_fpu(target);
			if (ret)
			return ret;

	set_stopped_child_used_math(target);		set_stopped_child_used_math(target);

	ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,		ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf,
	@@ -312,11 +328,14 @@ int fpregs_get(struct task_struct target, const struct user_regset regset,
	void kbuf, void __user ubuf)		void kbuf, void __user ubuf)
	{		{
	struct user_i387_ia32_struct env;		struct user_i387_ia32_struct env;
			int ret;

	if (!HAVE_HWFP)		if (!HAVE_HWFP)
	return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);		return fpregs_soft_get(target, regset, pos, count, kbuf, ubuf);

	init_fpu(target);		ret = init_fpu(target);
			if (ret)
			return ret;

	if (!cpu_has_fxsr) {		if (!cpu_has_fxsr) {
	return user_regset_copyout(&pos, &count, &kbuf, &ubuf,		return user_regset_copyout(&pos, &count, &kbuf, &ubuf,
	@@ -344,7 +363,10 @@ int fpregs_set(struct task_struct target, const struct user_regset regset,
	if (!HAVE_HWFP)		if (!HAVE_HWFP)
	return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);		return fpregs_soft_set(target, regset, pos, count, kbuf, ubuf);

	init_fpu(target);		ret = init_fpu(target);
			if (ret)
			return ret;

	set_stopped_child_used_math(target);		set_stopped_child_used_math(target);

	if (!cpu_has_fxsr) {		if (!cpu_has_fxsr) {

arch/x86/kernel/process.c

+19 −9

Original line number	Original line	Diff line number	Diff line
	@@ -5,24 +5,34 @@
	#include <linux/slab.h>		#include <linux/slab.h>
	#include <linux/sched.h>		#include <linux/sched.h>

	static struct kmem_cache *task_xstate_cachep;		struct kmem_cache *task_xstate_cachep;

	int arch_dup_task_struct(struct task_struct dst, struct task_struct src)		int arch_dup_task_struct(struct task_struct dst, struct task_struct src)
	{		{
	dst = src;		dst = src;
	dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep, GFP_KERNEL);		if (src->thread.xstate) {
			dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
			GFP_KERNEL);
	if (!dst->thread.xstate)		if (!dst->thread.xstate)
	return -ENOMEM;		return -ENOMEM;
	WARN_ON((unsigned long)dst->thread.xstate & 15);		WARN_ON((unsigned long)dst->thread.xstate & 15);
	memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);		memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
			}
	return 0;		return 0;
	}		}

	void free_thread_info(struct thread_info *ti)		void free_thread_xstate(struct task_struct *tsk)
	{		{
	kmem_cache_free(task_xstate_cachep, ti->task->thread.xstate);		if (tsk->thread.xstate) {
	ti->task->thread.xstate = NULL;		kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
			tsk->thread.xstate = NULL;
			}
			}


			void free_thread_info(struct thread_info *ti)
			{
			free_thread_xstate(ti->task);
	free_pages((unsigned long)(ti), get_order(THREAD_SIZE));		free_pages((unsigned long)(ti), get_order(THREAD_SIZE));
	}		}

arch/x86/kernel/process_32.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -521,6 +521,10 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
	regs->cs = __USER_CS;		regs->cs = __USER_CS;
	regs->ip = new_ip;		regs->ip = new_ip;
	regs->sp = new_sp;		regs->sp = new_sp;
			/*
			* Free the old FP and other extended state
			*/
			free_thread_xstate(current);
	}		}
	EXPORT_SYMBOL_GPL(start_thread);		EXPORT_SYMBOL_GPL(start_thread);

arch/x86/kernel/process_64.c

+4 −0

Original line number	Original line	Diff line number	Diff line
	@@ -533,6 +533,10 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp)
	regs->ss = __USER_DS;		regs->ss = __USER_DS;
	regs->flags = 0x200;		regs->flags = 0x200;
	set_fs(USER_DS);		set_fs(USER_DS);
			/*
			* Free the old FP and other extended state
			*/
			free_thread_xstate(current);
	}		}
	EXPORT_SYMBOL_GPL(start_thread);		EXPORT_SYMBOL_GPL(start_thread);

arch/x86/kernel/traps_32.c

+15 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1148,9 +1148,22 @@ asmlinkage void math_state_restore(void)
	struct thread_info *thread = current_thread_info();		struct thread_info *thread = current_thread_info();
	struct task_struct *tsk = thread->task;		struct task_struct *tsk = thread->task;

			if (!tsk_used_math(tsk)) {
			local_irq_enable();
			/*
			* does a slab alloc which can sleep
			*/
			if (init_fpu(tsk)) {
			/*
			* ran out of memory!
			*/
			do_group_exit(SIGKILL);
			return;
			}
			local_irq_disable();
			}

	clts(); /* Allow maths ops (or we recurse) */		clts(); /* Allow maths ops (or we recurse) */
	if (!tsk_used_math(tsk))
	init_fpu(tsk);
	restore_fpu(tsk);		restore_fpu(tsk);
	thread->status \|= TS_USEDFPU; /* So we fnsave on switch_to() */		thread->status \|= TS_USEDFPU; /* So we fnsave on switch_to() */
	tsk->fpu_counter++;		tsk->fpu_counter++;