/*
 * Copyright 2010 Tilera Corporation. All Rights Reserved.
 * Copyright 2015 Regents of the University of California
 * Copyright 2017 SiFive
 *
 *   This program is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU General Public License
 *   as published by the Free Software Foundation, version 2.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 * Copied from arch/tile/kernel/ptrace.c
 */

#include <asm/ptrace.h>
#include <asm/syscall.h>
#include <asm/thread_info.h>
#include <linux/ptrace.h>
#include <linux/elf.h>
#include <linux/regset.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/tracehook.h>
#include <trace/events/syscalls.h>

enum riscv_regset {
        REGSET_X,
#ifdef CONFIG_FPU
        REGSET_F,
#endif
};

static int riscv_gpr_get(struct task_struct *target,
                         const struct user_regset *regset,
                         unsigned int pos, unsigned int count,
                         void *kbuf, void __user *ubuf)
{
        struct pt_regs *regs;

        regs = task_pt_regs(target);
        return user_regset_copyout(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
}

static int riscv_gpr_set(struct task_struct *target,
                         const struct user_regset *regset,
                         unsigned int pos, unsigned int count,
                         const void *kbuf, const void __user *ubuf)
{
        int ret;
        struct pt_regs *regs;

        regs = task_pt_regs(target);
        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, regs, 0, -1);
        return ret;
}

#ifdef CONFIG_FPU
static int riscv_fpr_get(struct task_struct *target,
                         const struct user_regset *regset,
                         unsigned int pos, unsigned int count,
                         void *kbuf, void __user *ubuf)
{
        int ret;
        struct __riscv_d_ext_state *fstate = &target->thread.fstate;

        ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
                                  offsetof(struct __riscv_d_ext_state, fcsr));
        if (!ret) {
                ret = user_regset_copyout(&pos, &count, &kbuf, &ubuf, fstate, 0,
                                          offsetof(struct __riscv_d_ext_state, fcsr) +
                                          sizeof(fstate->fcsr));
        }

        return ret;
}

static int riscv_fpr_set(struct task_struct *target,
                         const struct user_regset *regset,
                         unsigned int pos, unsigned int count,
                         const void *kbuf, const void __user *ubuf)
{
        int ret;
        struct __riscv_d_ext_state *fstate = &target->thread.fstate;

        ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
                                 offsetof(struct __riscv_d_ext_state, fcsr));
        if (!ret) {
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, fstate, 0,
                                         offsetof(struct __riscv_d_ext_state, fcsr) +
                                         sizeof(fstate->fcsr));
        }

        return ret;
}
#endif

static const struct user_regset riscv_user_regset[] = {
        [REGSET_X] = {
                .core_note_type = NT_PRSTATUS,
                .n = ELF_NGREG,
                .size = sizeof(elf_greg_t),
                .align = sizeof(elf_greg_t),
                .get = &riscv_gpr_get,
                .set = &riscv_gpr_set,
        },
#ifdef CONFIG_FPU
        [REGSET_F] = {
                .core_note_type = NT_PRFPREG,
                .n = ELF_NFPREG,
                .size = sizeof(elf_fpreg_t),
                .align = sizeof(elf_fpreg_t),
                .get = &riscv_fpr_get,
                .set = &riscv_fpr_set,
        },
#endif
};

static const struct user_regset_view riscv_user_native_view = {
        .name = "riscv",
        .e_machine = EM_RISCV,
        .regsets = riscv_user_regset,
        .n = ARRAY_SIZE(riscv_user_regset),
};

const struct user_regset_view *task_user_regset_view(struct task_struct *task)
{
        return &riscv_user_native_view;
}

void ptrace_disable(struct task_struct *child)
{
        clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
}

long arch_ptrace(struct task_struct *child, long request,
                 unsigned long addr, unsigned long data)
{
        long ret = -EIO;

        switch (request) {
        default:
                ret = ptrace_request(child, request, addr, data);
                break;
        }

        return ret;
}

/*
 * Allows PTRACE_SYSCALL to work.  These are called from entry.S in
 * {handle,ret_from}_syscall.
 */
void do_syscall_trace_enter(struct pt_regs *regs)
{
        if (test_thread_flag(TIF_SYSCALL_TRACE))
                if (tracehook_report_syscall_entry(regs))
                        syscall_set_nr(current, regs, -1);

#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
                trace_sys_enter(regs, syscall_get_nr(current, regs));
#endif
}

void do_syscall_trace_exit(struct pt_regs *regs)
{
        if (test_thread_flag(TIF_SYSCALL_TRACE))
                tracehook_report_syscall_exit(regs, 0);

#ifdef CONFIG_HAVE_SYSCALL_TRACEPOINTS
        if (test_thread_flag(TIF_SYSCALL_TRACEPOINT))
                trace_sys_exit(regs, regs->regs[0]);
#endif
}