linux-kernel - Re: [PATCH] ARC: Change ld.as instruction to regular ld.

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Date:   Thu, 25 Aug 2016 12:05:19 +0000
From:   Alexey Brodkin <Alexey.Brodkin@...opsys.com>
To:     "liavr@...lanox.com" <liavr@...lanox.com>
CC:     Cupertino Miranda <Cupertino.Miranda@...opsys.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "eladkan@...lanox.com" <eladkan@...lanox.com>,
        "noamca@...lanox.com" <noamca@...lanox.com>,
        "Vineet Gupta" <Vineet.Gupta1@...opsys.com>,
        "linux-snps-arc@...ts.infradead.org" 
        <linux-snps-arc@...ts.infradead.org>
Subject: Re: [PATCH] ARC: Change ld.as instruction to regular ld.

Hi Liav,

On Wed, 2016-08-17 at 09:23 +0300, Liav Rehana wrote:
> From: Liav Rehana <liavr@...lanox.com>
> 
> User mode callee regs are explicitly collected before signal delivery
> or breakpoint trap. r25 is special for kernel as it serves as task
> pointer, so user mode value is clobbered very early. It is saved in
> pt_regs where generally only scratch (caller saved) res are saved.
> The code to access the corresponding pt_regs location had a subtle bug
> as it was using load/store with scaling of offset, whereas the offset
> was already byte wise correct. So fix this by replacing LD.AS with a
> standard LD
> 
> Signed-off-by: Liav Rehana <liavr@...lanox.com>

That nice patch really fixes quite annoying issue when r25 got
printed improperly in gdb!

So

Tested-by: Alexey Brodkin <abrodkin@...opsys.com>