linux-kernel - Re: [PATCH]X86:reboot.c Add some dmi entries to pci_reboot_dmi

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Date:	Wed, 02 Jun 2010 06:32:40 -0700
From:	"Justin P. Mattock" <justinmattock@...il.com>
To:	Alan Cox <alan@...rguk.ukuu.org.uk>
CC:	Matthew Garrett <mjg59@...f.ucam.org>, x86@...nel.org,
	tglx@...utronix.de, linux-kernel@...r.kernel.org
Subject: Re: [PATCH]X86:reboot.c Add some dmi entries to pci_reboot_dmi_table.

On 06/02/2010 05:08 AM, Alan Cox wrote:
> On Tue, 1 Jun 2010 22:48:20 +0100
> Matthew Garrett<mjg59@...f.ucam.org>  wrote:
>
>> On Tue, Jun 01, 2010 at 02:43:12PM -0700, Justin P. Mattock wrote:
>>> On 06/01/2010 02:29 PM, Matthew Garrett wrote:
>>>> So, just to be clear, you run this as root and it immediately returns
>>>> you to the prompt? This seems unlikely.
>>>
>>> yep.. with the above code
>>> I (save to a file) then
>>> non-root gcc reboot.c -o reboot
>>> then su
>>> ./reboot
>>> just bake to the command prompt
>>
>> Are you running some sort of security policy that might block hardware
>> access?
>
> 	Try
>
> 	if (iopl(...))
> 		perror
>
> ... (or strace it running as root)
>


o.k. here's the code with perror, and strace:


#include <sys/io.h>
#include <stdio.h>

int main() {
	iopl(3);
	outb(0xfe, 0x64);
	perror("something broke");
}

output in terminal:
something broke: Success


strace:

execve("./reboot", ["./reboot"], [/* 42 vars */]) = 0
brk(0)                                  = 0x601000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f0f50247000
access("/etc/ld.so.preload", R_OK)      = -1 ENOENT (No such file or 
directory)
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat(3, {st_mode=S_IFREG|0644, st_size=80596, ...}) = 0
mmap(NULL, 80596, PROT_READ, MAP_PRIVATE, 3, 0) = 0x7f0f50233000
close(3)                                = 0
open("/lib64/libc.so.6", O_RDONLY)      = 3
read(3, 
"\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0>\0\1\0\0\0p\355\241.;\0\0\0"...,
832) = 832
fstat(3, {st_mode=S_IFREG|0755, st_size=1838360, ...}) = 0
mmap(0x3b2ea00000, 3664040, PROT_READ|PROT_EXEC,
MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0x3b2ea00000
mprotect(0x3b2eb75000, 2097152, PROT_NONE) = 0
mmap(0x3b2ed75000, 20480, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x175000) = 0x3b2ed75000
mmap(0x3b2ed7a000, 18600, PROT_READ|PROT_WRITE,
MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x3b2ed7a000
close(3)                                = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f0f50232000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f0f50231000
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f0f50230000
arch_prctl(ARCH_SET_FS, 0x7f0f50231700) = 0
mprotect(0x3b2ed75000, 16384, PROT_READ) = 0
mprotect(0x3b2e61e000, 4096, PROT_READ) = 0
munmap(0x7f0f50233000, 80596)           = 0
iopl(0x3)                               = 0
dup(2)                                  = 3
fcntl(3, F_GETFL)                       = 0x8002 (flags O_RDWR|O_LARGEFILE)
brk(0)                                  = 0x601000
brk(0x622000)                           = 0x622000
fstat(3, {st_mode=S_IFCHR|0620, st_rdev=makedev(136, 0), ...}) = 0
mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1,
0) = 0x7f0f50246000
lseek(3, 0, SEEK_CUR)                   = -1 ESPIPE (Illegal seek)
write(3, "something broke: Success\n", 25something broke: Success
) = 25
close(3)                                = 0
munmap(0x7f0f50246000, 4096)            = 0
exit_group(0)                           = ?

what/where does one look for this keycode
if I may say?

Justin P. Mattock
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