1 #include <linux/sched.h>
2 #include <linux/slab.h>
3 #include <asm/processor.h>
4 #include <asm/fpu.h>
5 
init_fpu(struct task_struct * tsk)6 int init_fpu(struct task_struct *tsk)
7 {
8 	if (tsk_used_math(tsk)) {
9 		if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
10 			unlazy_fpu(tsk, task_pt_regs(tsk));
11 		return 0;
12 	}
13 
14 	/*
15 	 * Memory allocation at the first usage of the FPU and other state.
16 	 */
17 	if (!tsk->thread.xstate) {
18 		tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
19 						      GFP_KERNEL);
20 		if (!tsk->thread.xstate)
21 			return -ENOMEM;
22 	}
23 
24 	if (boot_cpu_data.flags & CPU_HAS_FPU) {
25 		struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
26 		memset(fp, 0, xstate_size);
27 		fp->fpscr = FPSCR_INIT;
28 	} else {
29 		struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
30 		memset(fp, 0, xstate_size);
31 		fp->fpscr = FPSCR_INIT;
32 	}
33 
34 	set_stopped_child_used_math(tsk);
35 	return 0;
36 }
37 
38 #ifdef CONFIG_SH_FPU
__fpu_state_restore(void)39 void __fpu_state_restore(void)
40 {
41 	struct task_struct *tsk = current;
42 
43 	restore_fpu(tsk);
44 
45 	task_thread_info(tsk)->status |= TS_USEDFPU;
46 	tsk->fpu_counter++;
47 }
48 
fpu_state_restore(struct pt_regs * regs)49 void fpu_state_restore(struct pt_regs *regs)
50 {
51 	struct task_struct *tsk = current;
52 
53 	if (unlikely(!user_mode(regs))) {
54 		printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
55 		BUG();
56 		return;
57 	}
58 
59 	if (!tsk_used_math(tsk)) {
60 		local_irq_enable();
61 		/*
62 		 * does a slab alloc which can sleep
63 		 */
64 		if (init_fpu(tsk)) {
65 			/*
66 			 * ran out of memory!
67 			 */
68 			do_group_exit(SIGKILL);
69 			return;
70 		}
71 		local_irq_disable();
72 	}
73 
74 	grab_fpu(regs);
75 
76 	__fpu_state_restore();
77 }
78 
BUILD_TRAP_HANDLER(fpu_state_restore)79 BUILD_TRAP_HANDLER(fpu_state_restore)
80 {
81 	TRAP_HANDLER_DECL;
82 
83 	fpu_state_restore(regs);
84 }
85 #endif /* CONFIG_SH_FPU */
86