arch/sh/kernel/cpu/fpu.c

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