/*
 * Copyright (C) 2004 Jeff Dike (jdike@addtoit.com)
 * Licensed under the GPL
 */

#ifndef __SYSDEP_STUB_H
#define __SYSDEP_STUB_H

#include <stddef.h>
#include <asm/ptrace.h>
#include <generated/asm-offsets.h>

#define STUB_MMAP_NR __NR_mmap2
#define MMAP_OFFSET(o) ((o) >> UM_KERN_PAGE_SHIFT)

static __always_inline long stub_syscall0(long syscall)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall1(long syscall, long arg1)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall2(long syscall, long arg1, long arg2)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
                        "c" (arg2)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall3(long syscall, long arg1, long arg2,
                                          long arg3)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
                        "c" (arg2), "d" (arg3)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall4(long syscall, long arg1, long arg2,
                                          long arg3, long arg4)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
                        "c" (arg2), "d" (arg3), "S" (arg4)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall5(long syscall, long arg1, long arg2,
                                          long arg3, long arg4, long arg5)
{
        long ret;

        __asm__ volatile ("int $0x80" : "=a" (ret) : "0" (syscall), "b" (arg1),
                        "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
                        : "memory");

        return ret;
}

static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
                                          long arg3, long arg4, long arg5,
                                          long arg6)
{
        struct syscall_args {
                int ebx, ebp;
        } args = { arg1, arg6 };
        long ret;

        __asm__ volatile ("pushl %%ebp;"
                        "movl 0x4(%%ebx),%%ebp;"
                        "movl (%%ebx),%%ebx;"
                        "int $0x80;"
                        "popl %%ebp"
                        : "=a" (ret)
                        : "0" (syscall), "b" (&args),
                        "c" (arg2), "d" (arg3), "S" (arg4), "D" (arg5)
                        : "memory");

        return ret;
}

static __always_inline void trap_myself(void)
{
        __asm("int3");
}

static __always_inline void *get_stub_data(void)
{
        unsigned long ret;

        asm volatile (
                "call _here_%=;"
                "_here_%=:"
                "popl %0;"
                "andl %1, %0 ;"
                "addl %2, %0 ;"
                : "=a" (ret)
                : "g" (~(UM_KERN_PAGE_SIZE - 1)),
                  "g" (UM_KERN_PAGE_SIZE));

        return (void *)ret;
}

#define stub_start(fn)                                                  \
        asm volatile (                                                  \
                "subl %0,%%esp ;"                                       \
                "movl %1, %%eax ; "                                     \
                "call *%%eax ;"                                         \
                :: "i" (STUB_SIZE),                                     \
                   "i" (&fn))

static __always_inline void
stub_seccomp_restore_state(struct stub_data_arch *arch)
{
        for (int i = 0; i < sizeof(arch->tls) / sizeof(arch->tls[0]); i++) {
                if (arch->sync & (1 << i))
                        stub_syscall1(__NR_set_thread_area,
                                      (unsigned long) &arch->tls[i]);
        }

        arch->sync = 0;
}

#endif