/* SPDX-License-Identifier: GPL-2.0-only */
/*
 * Access to user system call parameters and results
 *
 * Copyright (C) 2008-2009 Red Hat, Inc.  All rights reserved.
 *
 * See asm-generic/syscall.h for descriptions of what we must do here.
 */

#ifndef _ASM_X86_SYSCALL_H
#define _ASM_X86_SYSCALL_H

#include <uapi/linux/audit.h>
#include <linux/sched.h>
#include <linux/err.h>
#include <asm/thread_info.h>    /* for TS_COMPAT */
#include <asm/unistd.h>

/* This is used purely for kernel/trace/trace_syscalls.c */
typedef long (*sys_call_ptr_t)(const struct pt_regs *);
extern const sys_call_ptr_t sys_call_table[];

/*
 * These may not exist, but still put the prototypes in so we
 * can use IS_ENABLED().
 */
extern long ia32_sys_call(const struct pt_regs *, unsigned int nr);
extern long x32_sys_call(const struct pt_regs *, unsigned int nr);
extern long x64_sys_call(const struct pt_regs *, unsigned int nr);

/*
 * Only the low 32 bits of orig_ax are meaningful, so we return int.
 * This importantly ignores the high bits on 64-bit, so comparisons
 * sign-extend the low 32 bits.
 */
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
        return regs->orig_ax;
}

static inline void syscall_set_nr(struct task_struct *task,
                                  struct pt_regs *regs,
                                  int nr)
{
        regs->orig_ax = nr;
}

static inline void syscall_rollback(struct task_struct *task,
                                    struct pt_regs *regs)
{
        regs->ax = regs->orig_ax;
}

static inline long syscall_get_error(struct task_struct *task,
                                     struct pt_regs *regs)
{
        unsigned long error = regs->ax;
#ifdef CONFIG_IA32_EMULATION
        /*
         * TS_COMPAT is set for 32-bit syscall entries and then
         * remains set until we return to user mode.
         */
        if (task->thread_info.status & (TS_COMPAT|TS_I386_REGS_POKED))
                /*
                 * Sign-extend the value so (int)-EFOO becomes (long)-EFOO
                 * and will match correctly in comparisons.
                 */
                error = (long) (int) error;
#endif
        return IS_ERR_VALUE(error) ? error : 0;
}

static inline long syscall_get_return_value(struct task_struct *task,
                                            struct pt_regs *regs)
{
        return regs->ax;
}

static inline void syscall_set_return_value(struct task_struct *task,
                                            struct pt_regs *regs,
                                            int error, long val)
{
        regs->ax = (long) error ?: val;
}

#ifdef CONFIG_X86_32

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

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

static inline int syscall_get_arch(struct task_struct *task)
{
        return AUDIT_ARCH_I386;
}

#else    /* CONFIG_X86_64 */

static inline void syscall_get_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
        if (task->thread_info.status & TS_COMPAT) {
                *args++ = regs->bx;
                *args++ = regs->cx;
                *args++ = regs->dx;
                *args++ = regs->si;
                *args++ = regs->di;
                *args   = regs->bp;
        } else
# endif
        {
                *args++ = regs->di;
                *args++ = regs->si;
                *args++ = regs->dx;
                *args++ = regs->r10;
                *args++ = regs->r8;
                *args   = regs->r9;
        }
}

static inline void syscall_set_arguments(struct task_struct *task,
                                         struct pt_regs *regs,
                                         const unsigned long *args)
{
# ifdef CONFIG_IA32_EMULATION
        if (task->thread_info.status & TS_COMPAT) {
                regs->bx = *args++;
                regs->cx = *args++;
                regs->dx = *args++;
                regs->si = *args++;
                regs->di = *args++;
                regs->bp = *args;
        } else
# endif
        {
                regs->di = *args++;
                regs->si = *args++;
                regs->dx = *args++;
                regs->r10 = *args++;
                regs->r8 = *args++;
                regs->r9 = *args;
        }
}

static inline int syscall_get_arch(struct task_struct *task)
{
        /* x32 tasks should be considered AUDIT_ARCH_X86_64. */
        return (IS_ENABLED(CONFIG_IA32_EMULATION) &&
                task->thread_info.status & TS_COMPAT)
                ? AUDIT_ARCH_I386 : AUDIT_ARCH_X86_64;
}

bool do_syscall_64(struct pt_regs *regs, int nr);
void do_int80_emulation(struct pt_regs *regs);

#endif  /* CONFIG_X86_32 */

void do_int80_syscall_32(struct pt_regs *regs);
bool do_fast_syscall_32(struct pt_regs *regs);
bool do_SYSENTER_32(struct pt_regs *regs);

#endif  /* _ASM_X86_SYSCALL_H */