From: Bill Gatliff <bgat@billgatliff•com>
To: Bill Gatliff <bgat@billgatliff•com>,
gdb@sourceware•org, linuxppc-embedded@ozlabs•org
Subject: Re: Gdbserver syscall clobber
Date: Mon, 23 Jul 2007 10:37:13 -0500 [thread overview]
Message-ID: <46A4CB29.9080705@billgatliff.com> (raw)
In-Reply-To: <20070718183143.GA25324@caradoc.them.org>
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Daniel Jacobowitz wrote:
> On Wed, Jul 18, 2007 at 12:59:42PM -0500, Bill Gatliff wrote:
>
>> Now, I'm a little rusty on PPC asm (I've been doing a lot of ARM
>> lately), but it looks to me like the kernel is setting bit 0 in CR0
>> (oris r10, r10, 0x1000) a.k.a LT, but the user side is looking at CR0
>> (bnslr+) bit 3 a.k.a. SO. Or maybe the other way around, I'm not sure
>> after reading Sections 1.2 and 2.1 of the Programming Environments manual.
>>
>
> It's not checking for restart here - userspace isn't supposed to have to.
> It's probably checking for error. Check for the bit of kernel code
> that's supposed to back you up two instructions.
>
>
I don't see it in this kernel. What I see is this after the call to the
syscall handler:
li r10,-_LAST_ERRNO
cmpl 0,r3,r10
blt 30f
neg r3,r3
cmpi 0,r3,ERESTARTNOHAND
bne 22f
li r3,EINTR
22: lwz r10,_CCR(r1) /* Set SO bit in CR */
oris r10,r10,0x1000
stw r10,_CCR(r1)
30: stw r3,GPR3(r1) /* Update return value */
b ret_from_except
66: li r3,ENOSYS
b 22b
?
--
Bill Gatliff
bgat@billgatliff•com
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next prev parent reply other threads:[~2007-07-23 15:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-16 15:43 Gdbserver syscall clobber Bill Gatliff
2007-07-16 15:53 ` Daniel Jacobowitz
2007-07-18 17:42 ` Bill Gatliff
2007-07-18 17:59 ` Bill Gatliff
2007-07-18 18:31 ` Daniel Jacobowitz
2007-07-23 15:37 ` Bill Gatliff [this message]
2007-07-23 15:38 ` Bill Gatliff
2007-07-23 16:06 ` Bill Gatliff
2007-07-23 16:15 ` Daniel Jacobowitz
2007-07-26 16:28 ` Bill Gatliff
2007-07-23 16:19 ` Andreas Schwab
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