arch/sh/kernel/cpu/fpu.c

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