1// SPDX-License-Identifier: GPL-2.0
2#include <linux/mm.h>
3#include <linux/kernel.h>
4#include <linux/slab.h>
5#include <linux/sched/signal.h>
6#include <linux/sched/task_stack.h>
7#include <linux/export.h>
8#include <linux/stackprotector.h>
9#include <asm/fpu.h>
10#include <asm/ptrace.h>
11
12struct kmem_cache *task_xstate_cachep = NULL;
13unsigned int xstate_size;
14
15#ifdef CONFIG_STACKPROTECTOR
16unsigned long __stack_chk_guard __read_mostly;
17EXPORT_SYMBOL(__stack_chk_guard);
18#endif
19
20/*
21 * this gets called so that we can store lazy state into memory and copy the
22 * current task into the new thread.
23 */
24int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
25{
26	unlazy_fpu(src, task_pt_regs(src));
27	*dst = *src;
28
29	if (src->thread.xstate) {
30		dst->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
31						      GFP_KERNEL);
32		if (!dst->thread.xstate)
33			return -ENOMEM;
34		memcpy(dst->thread.xstate, src->thread.xstate, xstate_size);
35	}
36
37	return 0;
38}
39
40void free_thread_xstate(struct task_struct *tsk)
41{
42	if (tsk->thread.xstate) {
43		kmem_cache_free(task_xstate_cachep, tsk->thread.xstate);
44		tsk->thread.xstate = NULL;
45	}
46}
47
48void arch_release_task_struct(struct task_struct *tsk)
49{
50	free_thread_xstate(tsk);
51}
52
53void arch_task_cache_init(void)
54{
55	if (!xstate_size)
56		return;
57
58	task_xstate_cachep = kmem_cache_create("task_xstate", xstate_size,
59					       __alignof__(union thread_xstate),
60					       SLAB_PANIC, NULL);
61}
62
63#ifdef CONFIG_SH_FPU_EMU
64# define HAVE_SOFTFP	1
65#else
66# define HAVE_SOFTFP	0
67#endif
68
69void init_thread_xstate(void)
70{
71	if (boot_cpu_data.flags & CPU_HAS_FPU)
72		xstate_size = sizeof(struct sh_fpu_hard_struct);
73	else if (HAVE_SOFTFP)
74		xstate_size = sizeof(struct sh_fpu_soft_struct);
75	else
76		xstate_size = 0;
77}
78