arch/sh/kernel/cpu/fpu.c

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