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 | |
11 | int 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(cachep: 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 |
44 | void __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 | |
54 | void 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 | |
86 | BUILD_TRAP_HANDLER(fpu_state_restore) |
87 | { |
88 | TRAP_HANDLER_DECL; |
89 | |
90 | fpu_state_restore(regs); |
91 | } |
92 | #endif /* CONFIG_SH_FPU */ |
93 | |