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