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