// SPDX-License-Identifier: GPL-2.0
#include <linux/sched/signal.h>
#include <linux/sched/task.h>
#include <linux/sched/task_stack.h>
#include <linux/slab.h>
#include <asm/processor.h>
#include <asm/fpu.h>
#include <asm/traps.h>
#include <asm/ptrace.h>

int init_fpu(struct task_struct *tsk)
{
        if (tsk_used_math(tsk)) {
                if ((boot_cpu_data.flags & CPU_HAS_FPU) && tsk == current)
                        unlazy_fpu(tsk, task_pt_regs(tsk));
                return 0;
        }

        /*
         * Memory allocation at the first usage of the FPU and other state.
         */
        if (!tsk->thread.xstate) {
                tsk->thread.xstate = kmem_cache_alloc(task_xstate_cachep,
                                                      GFP_KERNEL);
                if (!tsk->thread.xstate)
                        return -ENOMEM;
        }

        if (boot_cpu_data.flags & CPU_HAS_FPU) {
                struct sh_fpu_hard_struct *fp = &tsk->thread.xstate->hardfpu;
                memset(fp, 0, xstate_size);
                fp->fpscr = FPSCR_INIT;
        } else {
                struct sh_fpu_soft_struct *fp = &tsk->thread.xstate->softfpu;
                memset(fp, 0, xstate_size);
                fp->fpscr = FPSCR_INIT;
        }

        set_stopped_child_used_math(tsk);
        return 0;
}

#ifdef CONFIG_SH_FPU
void __fpu_state_restore(void)
{
        struct task_struct *tsk = current;

        restore_fpu(tsk);

        task_thread_info(tsk)->status |= TS_USEDFPU;
        tsk->thread.fpu_counter++;
}

void fpu_state_restore(struct pt_regs *regs)
{
        struct task_struct *tsk = current;

        if (unlikely(!user_mode(regs))) {
                printk(KERN_ERR "BUG: FPU is used in kernel mode.\n");
                BUG();
                return;
        }

        if (!tsk_used_math(tsk)) {
                int ret;
                /*
                 * does a slab alloc which can sleep
                 */
                local_irq_enable();
                ret = init_fpu(tsk);
                local_irq_disable();
                if (ret) {
                        /*
                         * ran out of memory!
                         */
                        force_sig(SIGKILL);
                        return;
                }
        }

        grab_fpu(regs);

        __fpu_state_restore();
}

BUILD_TRAP_HANDLER(fpu_state_restore)
{
        TRAP_HANDLER_DECL;

        fpu_state_restore(regs);
}
#endif /* CONFIG_SH_FPU */