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

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/sched/signal.h>
   3#include <linux/sched/task.h>
   4#include <linux/sched/task_stack.h>
   5#include <linux/slab.h>
   6#include <asm/processor.h>
   7#include <asm/fpu.h>
   8#include <asm/traps.h>
   9#include <asm/ptrace.h>
  10
  11int init_fpu(struct task_struct *tsk)
  12{
  13        if (tsk_used_math(tsk)) {
  14                if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
  15                        unlazy_fpu(tsk, task_pt_regs(tsk));
  16                return 0;
  17        }
  18
  19        /*
  20         * Memory allocation at the first usage of the FPU and other state.
  21         */
  22        if (!tsk->thread.xstate) {
  23                tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
  24                                                      GFP_KERNEL);
  25                if (!tsk->thread.xstate)
  26                        return -ENOMEM;
  27        }
  28
  29        if (boot_cpu_data.flags & CPU_HAS_FPU) {
  30                struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
  31                memset(fp, 0, xstate_size);
  32                fp->fpscr = FPSCR_INIT;
  33        } else {
  34                struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
  35                memset(fp, 0, xstate_size);
  36                fp->fpscr = FPSCR_INIT;
  37        }
  38
  39        set_stopped_child_used_math(tsk);
  40        return 0;
  41}
  42
  43#ifdef CONFIG_SH_FPU
  44void __fpu_state_restore(void)
  45{
  46        struct task_struct *tsk = current;
  47
  48        restore_fpu(tsk);
  49
  50        task_thread_info(tsk)->status |= TS_USEDFPU;
  51        tsk->thread.fpu_counter++;
  52}
  53
  54void fpu_state_restore(struct pt_regs *regs)
  55{
  56        struct task_struct *tsk = current;
  57
  58        if (unlikely(!user_mode(regs))) {
  59                printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
  60                BUG();
  61                return;
  62        }
  63
  64        if (!tsk_used_math(tsk)) {
  65                local_irq_enable();
  66                /*
  67                 * does a slab alloc which can sleep
  68                 */
  69                if (init_fpu(tsk)) {
  70                        /*
  71                         * ran out of memory!
  72                         */
  73                        do_group_exit(SIGKILL);
  74                        return;
  75                }
  76                local_irq_disable();
  77        }
  78
  79        grab_fpu(regs);
  80
  81        __fpu_state_restore();
  82}
  83
  84BUILD_TRAP_HANDLER(fpu_state_restore)
  85{
  86        TRAP_HANDLER_DECL;
  87
  88        fpu_state_restore(regs);
  89}
  90#endif /* CONFIG_SH_FPU */
  91