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From: Mike Frysinger <vapier.adi@gmail.com>
Date: Mon, 7 Dec 2009 05:10:11 -0500
Message-ID: <8bd0f97a0912070210m4f13e174y154fc82732ef136c@mail.gmail.com>
Subject: Re: [uClinux-dev] [PATCH/RFC] FDPIC: add hook for arches to customize 
	program header parsing
To: Jie Zhang <jie.zhang@analog.com>
Cc: David Howells <dhowells@redhat.com>,
       uClinux development list <uclinux-dev@uclinux.org>,
       linux-kernel@vger.kernel.org, Greg Ungerer <gerg@uclinux.org>,
       uclinux-dist-devel@blackfin.uclinux.org,
       David McCullough <davidm@snapgear.com>
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On Fri, Dec 4, 2009 at 19:28, Jie Zhang <wrote:
> On 12/05/2009 01:44 AM, David Howells wrote:
>> Mike Frysinger<vapier@gentoo.org>  wrote:
>>> The Blackfin port has custom program header flags/addresses for
>>> automatically loading regions into the dedicated on-chip SRAM.  So add a
>>> hook for ports to leverage.
>>
>> Now that I've ACK'd this, I feel I'm going to have to NAK it.  I'm not
>> against
>> the general concept, but:
>>
>>> +               do_munmap(mm, *maddr, phdr->p_memsz + *disp);
>>
>> There needs to be a mapping covering the SRAM region for the purposes of
>> the
>
> Our GDB is still lack of the feature to debug applications using SRAM.

semi true.  L1 text appears to work fine:
(gdb) stepi
0xffa02aac in moo ()
(gdb) dis
Dump of assembler code from 0xffa02aac to 0xffa02aec:
0xffa02aac <moo+0>:     LINK 0xc;               /* (12) */
0xffa02ab0 <moo+4>:     [FP + 0x8] = R0;
....

but L1 data doesnt seem to work (probably something simple to fix in
our kernel ptrace?):
(gdb) print i
Cannot access memory at address 0xff803e58

the simple code:
int i __attribute__((l1_data));

> So this part of code was not got exercised. So if we remove this line, can
> this patch got merged?

this code does get exercised -- it's run every time code is loaded
from initramfs for example.  the
-mike
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