From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir.fraser@eu.citrix.com>
Subject: Re: A question related with symbol reference?
Date: Tue, 18 Mar 2008 08:31:25 +0000
Message-ID: <C4052E5D.151CF%keir.fraser@eu.citrix.com>
References: <20080318055957.E984013692B@ncic.ac.cn>
Mime-Version: 1.0
Content-Type: text/plain;
	charset="GB2312"
Content-Transfer-Encoding: quoted-printable
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <20080318055957.E984013692B@ncic.ac.cn>
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Zang Hongyong <zanghongyong@ncic.ac.cn>, "fanghaifeng@ncic.ac.cn" <fanghaifeng@ncic.ac.cn>, xen-devel <xen-devel@lists.xensource.com>
List-Id: xen-devel@lists.xenproject.org

Assembly code does not need a function prototype or indeed any label
declaration to be able to reference that function/label.

 -- Keir

On 18/3/08 06:19, "Zang Hongyong" <zanghongyong@ncic.ac.cn> wrote:

> anyone can help?=A1=A1=A1=A1
> I'm confused too.
>=20
> =3D=3D=3D=3D=3D=3D=3D=3D 2008-03-18 14:04:50 =C4=FA=D4=DA=C0=B4=D0=C5=D6=D0=D0=B4=B5=C0=A3=BA =3D=3D=3D=3D=3D=3D=3D=3D
>=20
> hi, my friends:
>=20
> recently, i am reading the source codes about hypercall.
>=20
> First, i study a simple hypercall, for example, the "do_xen_version".
>=20
> In "xen-3.1.0-src\xen\common\kernel.c", the definition of "do_xen_version=
" is:
>=20
> DO(xen_version) (int cmd, XEN_GUEST_HANDLE(void) arg)
> {
> ....
> }
>=20
> according to the " #define DO(fn) long do_##fn ", the expanded form is
> "do_xen_version (...)".
>=20
> then, in the "xen-3.1.0-src\xen\arch\x86\x86_32\entry.S", there is an ite=
m in
> the "hypercall_table", like this:
>=20
> ENTRY(hypercall_table)
> ....
> .long do_xen_version
> ....
>=20
>=20
> as we all known, for a symbol reference of function there need to be a he=
ader
> file contained, or a "global" declaration.
>=20
> By searching the header files, i found the file,
> "xen-3.1.0-src\xen\include\xen\hypercall.h" that declared the function in=
 a
> form as follows:
>=20
> extern long
> do_xen_version(
> int cmd,
> XEN_GUEST_HANDLE(void) arg);
>=20
> But, i can not find where the file "hypercall.h" is contained in order to=
 link
> it with the reference of "do_xen_version" in the "entry.S"
>=20
> So, please help me, or give me some advice.
>=20
> thanks advance.
>=20
> 2008-03-18=20
>=20
>=20
>=20
> =B7=BF=BA=A3=B7=E5=20
>=20
>=20
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@lists.xensource.com
> http://lists.xensource.com/xen-devel