Re: Using sysarch specific syscalls in assembly?

From: alexander (arundel_at_h3c.de)
Date: 08/08/05

  • Next message: ari edelkind: "Re: Using sysarch specific syscalls in assembly?" 
    Date: Mon, 8 Aug 2005 22:09:49 +0200
To: freebsd-hackers@freebsd.org

    On Mon Aug 8 05, John Baldwin wrote:
    > 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

    Thx a lot. That worked.
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  • Next message: ari edelkind: "Re: Using sysarch specific syscalls in assembly?"