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

#ifndef __SYSDEP_STUB_H
#define __SYSDEP_STUB_H

#include <stddef.h>
#include <sysdep/ptrace_user.h>
#include <generated/asm-offsets.h>
#include <linux/stddef.h>
#include <asm/prctl.h>

#define STUB_MMAP_NR __NR_mmap
#define MMAP_OFFSET(o) (o)

#define __syscall_clobber "r11","rcx","memory"
#define __syscall "syscall"

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

        __asm__ volatile (__syscall
                : "=a" (ret)
                : "0" (syscall) : __syscall_clobber );

        return ret;
}

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

        __asm__ volatile (__syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1) : __syscall_clobber );

        return ret;
}

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

        __asm__ volatile (__syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1), "S" (arg2) : __syscall_clobber );

        return ret;
}

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

        __asm__ volatile (__syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3)
                : __syscall_clobber );

        return ret;
}

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

        __asm__ volatile ("movq %5,%%r10 ; " __syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
                  "g" (arg4)
                : __syscall_clobber, "r10" );

        return ret;
}

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

        __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; " __syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
                  "g" (arg4), "g" (arg5)
                : __syscall_clobber, "r10", "r8" );

        return ret;
}

static __always_inline long stub_syscall6(long syscall, long arg1, long arg2,
                                          long arg3, long arg4, long arg5,
                                          long arg6)
{
        long ret;

        __asm__ volatile ("movq %5,%%r10 ; movq %6,%%r8 ; movq %7,%%r9 ; "
                __syscall
                : "=a" (ret)
                : "0" (syscall), "D" (arg1), "S" (arg2), "d" (arg3),
                  "g" (arg4), "g" (arg5), "g" (arg6)
                : __syscall_clobber, "r10", "r8", "r9");

        return ret;
}

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

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

        asm volatile (
                "lea 0(%%rip), %0;"
                "andq %1, %0 ;"
                "addq %2, %0 ;"
                : "=a" (ret)
                : "g" (~(UM_KERN_PAGE_SIZE - 1)),
                  "g" (UM_KERN_PAGE_SIZE));

        return (void *)ret;
}

#define stub_start(fn)                                                  \
        asm volatile (                                                  \
                "subq %0,%%rsp ;"                                       \
                "movq %1,%%rax ;"                                       \
                "call *%%rax ;"                                         \
                :: "i" (STUB_SIZE),                                     \
                   "i" (&fn))

static __always_inline void
stub_seccomp_restore_state(struct stub_data_arch *arch)
{
        /*
         * We could use _writefsbase_u64/_writegsbase_u64 if the host reports
         * support in the hwcaps (HWCAP2_FSGSBASE).
         */
        if (arch->sync & STUB_SYNC_FS_BASE)
                stub_syscall2(__NR_arch_prctl, ARCH_SET_FS, arch->fs_base);
        if (arch->sync & STUB_SYNC_GS_BASE)
                stub_syscall2(__NR_arch_prctl, ARCH_SET_GS, arch->gs_base);

        arch->sync = 0;
}

#endif