lkml.org 
[lkml]   [2003]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectProblem with bootmem/mmap
Date
Dear all,

I'm allocating a large buffer at boot time (for later DMA purposes) using:

buf=alloc_bootmem_low_pages(1024*1024*500);

If I printk here, from init/main.c, I get:
buf=0xc1e14000
__va(buf)=0x81e14000
__pa(buf)=0x1e14000

Now, in user-space, I'm trying to get access to my buffer (as root), by
doing the following:

memfd=open("/dev/mem", O_RDWR);
my_buf=mmap(0, 1024*1024*501, PROT_READ|PROT_WRITE,
MAP_SHARED|MAP_FIXED, memfd, OFFSET);

I've tried all those addresses above, as the OFFSET, but it either generates
an illegal instruction,
or a segfault. Bit of a beginner, but learning fast, and I'd be _really_
greatful, if anyone could help me!

Many thanks,
Ed



begin 666 RMRL-Disclaimer.txt
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;<F%C='5A;" -#0T*<F5L871I;VYS:&EP+@T*
end

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:36    [W:0.035 / U:4.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site