1// SPDX-License-Identifier: GPL-2.0
2#include <linux/sched/signal.h>
3#include <linux/sched/task.h>
4#include <linux/sched/task_stack.h>
5#include <linux/slab.h>
6#include <asm/processor.h>
7#include <asm/fpu.h>
8#include <asm/traps.h>
9#include <asm/ptrace.h>
10
11int init_fpu(struct task_struct *tsk)
12{
13	if (tsk_used_math(tsk)) {
14		if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
15			unlazy_fpu(tsk, task_pt_regs(tsk));
16		return 0;
17	}
18
19	/*
20	 * Memory allocation at the first usage of the FPU and other state.
21	 */
22	if (!tsk->thread.xstate) {
23		tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
24						      GFP_KERNEL);
25		if (!tsk->thread.xstate)
26			return -ENOMEM;
27	}
28
29	if (boot_cpu_data.flags & CPU_HAS_FPU) {
30		struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
31		memset(fp, 0, xstate_size);
32		fp->fpscr = FPSCR_INIT;
33	} else {
34		struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
35		memset(fp, 0, xstate_size);
36		fp->fpscr = FPSCR_INIT;
37	}
38
39	set_stopped_child_used_math(tsk);
40	return 0;
41}
42
43#ifdef CONFIG_SH_FPU
44void __fpu_state_restore(void)
45{
46	struct task_struct *tsk = current;
47
48	restore_fpu(tsk);
49
50	task_thread_info(tsk)->status |= TS_USEDFPU;
51	tsk->thread.fpu_counter++;
52}
53
54void fpu_state_restore(struct pt_regs *regs)
55{
56	struct task_struct *tsk = current;
57
58	if (unlikely(!user_mode(regs))) {
59		printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
60		BUG();
61		return;
62	}
63
64	if (!tsk_used_math(tsk)) {
65		int ret;
66		/*
67		 * does a slab alloc which can sleep
68		 */
69		local_irq_enable();
70		ret = init_fpu(tsk);
71		local_irq_disable();
72		if (ret) {
73			/*
74			 * ran out of memory!
75			 */
76			force_sig(SIGKILL);
77			return;
78		}
79	}
80
81	grab_fpu(regs);
82
83	__fpu_state_restore();
84}
85
86BUILD_TRAP_HANDLER(fpu_state_restore)
87{
88	TRAP_HANDLER_DECL;
89
90	fpu_state_restore(regs);
91}
92#endif /* CONFIG_SH_FPU */
93