Date: Mon, 1 Dec 2008 05:07:37 -0800 (PST) From: Won De Erick <won.derick@yahoo.com> To: Christoph Mallon <christoph.mallon@gmx.de> Cc: freebsd-hackers@freebsd.org, Rink Springer <rink@FreeBSD.org>, freebsd-hardware@freebsd.org Subject: Re: Watchdog for Boser (HS-7001) Message-ID: <839504.20277.qm@web45816.mail.sp1.yahoo.com>
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>From: Won De Erick <won.derick@yahoo.com>
>>From: Christoph Mallon <christoph.mallon@gmx.de>
>>
>
>Won De Erick schrieb:
>>>> ----- Original Message ----
>>>
>>>> From: Rink Springer <rink@FreeBSD.org>
>>>>
>>>>
>>> On Mon, Dec 01, 2008 at 09:38:51AM +0100, Christoph Mallon wrote:
>>>>> Userland is not allowed to write to ports. That's the bus error you see. Also without a call to the exit syscall at the end, it will segfault.
>>>> Note that you can write to ports from userland by opening /dev/io - if
>>>> you have it opened, you can write to the ports.
>>>>
>>>
>>> I've added the following at the end
>>>
>>> mov eax, 1 ; SYS_exit
>>> call doint
>>>
>>> doint:
>>> int 0x80
>>> ret
>>>
>>> Besides, I can see the following at /dev
>>> crw------- 1 root wheel 0, 16 Nov 27 01:53 io
>>>
>>> How should I make this open? do i need to %include this?
>>
>>You're probably better of writing this in C. Here is a wrapper for the out instruction:
>>
>>static inline outb(unsigned short port, unsigned char data)
>>{
>> asm("outb %0, %1" : : "a" (data), "dN" (port));
>>}
>>
>>As Rink mentioned, you have to open /dev/io. The process must have super-user privileges, see io(4).
>
>will this be ok?
>int fd = open("/dev/fido", O_RDWR);
>
aww.. i mean int sio = open("/dev/io", O_RDWR);
>
>>
>>Regards
>> Christoph
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