kernel/arch/sh/kernel/cpu/fpu.c

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