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 local_irq_enable(); 66 /* 67 * does a slab alloc which can sleep 68 */ 69 if (init_fpu(tsk)) { 70 /* 71 * ran out of memory! 72 */ 73 do_group_exit(SIGKILL); 74 return; 75 } 76 local_irq_disable(); 77 } 78 79 grab_fpu(regs); 80 81 __fpu_state_restore(); 82 } 83 84 BUILD_TRAP_HANDLER(fpu_state_restore) 85 { 86 TRAP_HANDLER_DECL; 87 88 fpu_state_restore(regs); 89 } 90 #endif /* CONFIG_SH_FPU */ 91