From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tom Duffy <tomduffy@dslextreme.com>
Date: Thu, 13 Jan 2005 23:12:14 +0000
Subject: mmap(/dev/mem) causing sigbus
Message-Id: <1105657934.2527.96.camel@duffman>
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It seems that there is an issue with either mmap or mmap'ing /dev/mem on
sparc64.  A tool (mstflint) for flashing firmware for Mellanox
Infiniband HCA's is crashing on sparc64.  It mmap's /dev/mem and when it
accesses it, a bus error is generated.

Should this work?

Attached is a small test program to demonstrate.  Change BAR0 to
something in your PCI address space (grab an address from /proc/iomem).

# cat /proc/iomem
<snip>
  1ff00100000-1ff001fffff : 0000:81:00.0
    1ff00180680-1ff0018070f : ib_mthca
    1ff001f00d8-1ff001f00df : ib_mthca
  1ff00800000-1ff00ffffff : 0000:81:00.0
    1ff00800000-1ff00ffffff : ib_mthca
  1ff08000000-1ff0fffffff : 0000:81:00.0

# gdb ./mmap-test
(gdb) run
Starting program: /root/mmap-test
warning: linux_test_for_tracefork: unexpected result from waitpid (3298, st=
atus 0xb7f)

Program received signal SIGBUS, Bus error.
0x00010630 in main () at mmap-test.c:29
29              value=3D *( (unsigned*)(ptr + 0x000f0014) );
(gdb) print ptr
$1 =3D (void *) 0x7018c000
(gdb) print ptr + 0x000f0014
$2 =3D (void *) 0x7027c014
(gdb) x 0x7027c014
0x7027c014:     Cannot access memory at address 0x7027c014

# cat /proc/3317/maps
<snip>
7018c000-7028c000 rw-s 1ff00100000 00:0d 316                             /d=
ev/mem

# uname -a
Linux tat 2.6.10 #14 SMP Mon Jan 3 12:30:51 PST 2005 sparc64 GNU/Linux

-tduffy

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