Date: Mon, 8 Aug 2005 15:50:55 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-hackers@freebsd.org Subject: Re: Using sysarch specific syscalls in assembly? Message-ID: <200508081550.56292.jhb@FreeBSD.org> In-Reply-To: <20050808191910.GA91484@skatecity> References: <20050808191910.GA91484@skatecity>
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On Monday 08 August 2005 03:19 pm, alexander wrote: > Hi there. > > I wrote a program that needs to access I/O ports with the in/out > machinecodes. To gain priviliges to do so I have opened /dev/io. Now > somebody told me that I'd rather use i386_set_ioperm which will be much > saver, because of the port range limitation. Plus it will make the program > more portable because Linux does not have a /dev/io device node. > > i386_set_ioperm(2) states that this procedure is a system call. So it > should be easily accessable through assembly language and it's specific > syscall id. Unfortunately I wasn't able to find the syscall id in any of > the > syscalls.master files that are part of the source tree. > > <machine/sysarch.h> states that this is a sysarch specific syscall for i386 > (hence the i386_*). The following definitions are being made: > > #define I386_GET_IOPERM 3 > #define I386_SET_IOPERM 4 > > These syscall numbers however are already taken by read(2) and write(2). So > how can I make use of these i386 specific syscalls? Is it even possible? > > Thx in advance. You have to call the sysarch() system call. The first argument to it would be the operation (I386_GET_IOPERM, etc.). -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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