hexdumping /dev/mem

[Ian Lepore]

On Mon, 2015-03-16 at 16:41 -0700, Stanislav Sedov wrote:
> > On Mar 16, 2015, at 3:58 PM, Matas Perret Cantoni <perretcantonim at gmail.com> wrote:
> > 
> > I couldn't find any man page for "kdb" or "db", and the help command
> > of db didn't help much.
> 
> The only relevant manual pages are ddb(4) and ddb(8), I’m afraid.
> But they have plenty of information.  Nothing on devmap though.
> 

show devmap and show physmem are arm-specific commands I added a while
back, but didn't document anywhere except in the builtin help display.

Accessing device registers from ddb is possible because the access is
all within the kernel (unlike with /dev/[k]mem where the pages have to
be mapped into user space, which can't be done safely on arm).  But you
still have to be careful about what other device drivers might be doing
with the same registers (if there are drivers attached for that
hardware).

-- Ian