arch/sh/kernel/cpu/fpu.c

   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 */