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(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
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