/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Copyright (C) 2012 ARM Ltd.
 */
#ifndef __ASM_SYSCALL_H
#define __ASM_SYSCALL_H

#include <uapi/linux/audit.h>
#include <linux/compat.h>
#include <linux/err.h>

typedef long (*syscall_fn_t)(const struct pt_regs *regs);

extern const syscall_fn_t sys_call_table[];

#ifdef CONFIG_COMPAT
extern const syscall_fn_t compat_sys_call_table[];
#endif

static inline int syscall_get_nr(struct task_struct *task,
                                 struct pt_regs *regs)
{
        return regs->syscallno;
}

static inline void syscall_rollback(struct task_struct *task,
                                    struct pt_regs *regs)
{
        regs->regs[0] = regs->orig_x0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                                            struct pt_regs *regs)
{
        unsigned long val = regs->regs[0];

        if (is_compat_thread(task_thread_info(task)))
                val = sign_extend64(val, 31);

        return val;
}

static inline long syscall_get_error(struct task_struct *task,
                                     struct pt_regs *regs)
{
        unsigned long error = syscall_get_return_value(task, regs);

        return IS_ERR_VALUE(error) ? error : 0;
}

static inline void syscall_set_return_value(struct task_struct *task,
                                            struct pt_regs *regs,
                                            int error, long val)
{
        if (error)
                val = error;

        if (is_compat_thread(task_thread_info(task)))
                val = lower_32_bits(val);

        regs->regs[0] = val;
}

static inline void syscall_set_nr(struct task_struct *task,
                                  struct pt_regs *regs,
                                  int nr)
{
        regs->syscallno = nr;
        if (nr == -1) {
                /*
                 * When the syscall number is set to -1, the syscall will be
                 * skipped.  In this case the syscall return value has to be
                 * set explicitly, otherwise the first syscall argument is
                 * returned as the syscall return value.
                 */
                syscall_set_return_value(task, regs, -ENOSYS, 0);
        }
}

static inline void syscall_get_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         unsigned long *args)
{
        args[0] = regs->orig_x0;
        args[1] = regs->regs[1];
        args[2] = regs->regs[2];
        args[3] = regs->regs[3];
        args[4] = regs->regs[4];
        args[5] = regs->regs[5];
}

static inline void syscall_set_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         const unsigned long *args)
{
        regs->regs[0] = args[0];
        regs->regs[1] = args[1];
        regs->regs[2] = args[2];
        regs->regs[3] = args[3];
        regs->regs[4] = args[4];
        regs->regs[5] = args[5];

        /*
         * Also copy the first argument into orig_x0
         * so that syscall_get_arguments() would return it
         * instead of the previous value.
         */
        regs->orig_x0 = regs->regs[0];
}

/*
 * We don't care about endianness (__AUDIT_ARCH_LE bit) here because
 * AArch64 has the same system calls both on little- and big- endian.
 */
static inline int syscall_get_arch(struct task_struct *task)
{
        if (is_compat_thread(task_thread_info(task)))
                return AUDIT_ARCH_ARM;

        return AUDIT_ARCH_AARCH64;
}

int syscall_trace_enter(struct pt_regs *regs);
void syscall_trace_exit(struct pt_regs *regs);

#endif  /* __ASM_SYSCALL_H */