Subject: Re: A strange library

From: "Jacky Lam" <[email-masked]>
Date: Thu, 27 Jul 2000 19:08:30 +0800

Dear Philip,

    The Thumb instruction set? If I have to overcome this problem(btw, can
arm linux support thumb instruction?), what should I do? Upgrade the
compiler and kernel? I have tried before. But it is too complicated to
collect all the necessary patches.... Where can I find a complete
instruction and patches to do this?

    Thanks very much.

Jacky Lam
-----Original Message-----
From: Philip Blundell <[email-masked]>
To: Jacky Lam <[email-masked]>
Cc: [email-masked] <[email-masked]>
Date: Thursday, July 27, 2000 6:44 PM
Subject: Re: A strange library

>>    "Kernel panic: Unknown data abort code 4194304 [pc=020014e8,
>>*pc=e14192b0] LR=0x014e8"
>
>Looks like your version of the kernel doesn't handle aborting halfword
>instructions.  I think this was only recently added.
>
>p.
>
>
>
>unsubscribe: body of `unsubscribe linux-arm' to [email-masked]
>++        Please use [email-masked] for
++
>++                        kernel-related discussions.
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unsubscribe: body of `unsubscribe linux-arm' to [email-masked]
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---

From: Philip Blundell <[email-masked]>
Date: Thu, 27 Jul 2000 12:15:53 +0100

>    The Thumb instruction set?

No, this isn't Thumb.  The problem is that, on ARM7 based cores, if an 
instruction aborts the kernel needs to decode the faulting instruction to work 
out what to do.  It can handle most common cases, but not absolutely every 
instruction that can fault.  (For example, SWP still wasn't supported last 
time I looked; there have been a few reports of people having programs die 
because of this, too.)

The particular instruction you are having trouble with is LDRH, which is just 
an ARM 16-bit load.  If you upgrade to the latest kernel I think it will work.

>(btw, can arm linux support thumb instruction?),

People have done some work on this in the past but I don't know what the 
current status is.  As far as I know the kernel doesn't deal with Thumb yet.

p.

---

From: S A McConnell <[email-masked]>
Date: Thu, 27 Jul 2000 07:02:30 -0500

Cliff Brake [email-masked] supplied a patch for half-word support.
RMK included it in his latest patch.

SAM