[PATCH 0/3] kallsyms: remove special handling for CONFIG_ARM

From: Chris.Brandt@renesas.com (Chris Brandt)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 0/3] kallsyms: remove special handling for CONFIG_ARM
Date: Wed, 3 Feb 2016 14:15:16 +0000	[thread overview]
Message-ID: <HKXPR06MB056516B5DC41AB61AA39D8B28AD00@HKXPR06MB0565.apcprd06.prod.outlook.com> (raw)
In-Reply-To: <CAKv+Gu8ZTHAqviveLMizRKPfeXwb6kcXi4cVQNYVYuPcVMgMeQ@mail.gmail.com>

On 2 Feb 2016, Chris Brandt wrote 
> > And when a printed out the destination, I get:
> >
> >    Stubs at c09ff000 :00000000 BF006F20 EF9F0000 EA000064 etc...
> >
> > Notice the first entry is 0....that's not right...and we know it's using that
> > first __stubs_start symbol.
> >
>
> The first quantity after __stubs_start should be the address of vector_swi. Can
>  you check if the second value coincides with that?

Yes, it does.

bf006f20 T vector_swi

Which is why it booted once I modified the start address.

> This is caused by the fact that __stubs_start is not aligned correctly on XIP.
>
> Could you try this, please?
>
> diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S index 7160658fd5d4..a5b8e7b80d17 100644
> --- a/arch/arm/kernel/vmlinux.lds.S
> +++ b/arch/arm/kernel/vmlinux.lds.S
> @@ -164,8 +164,8 @@ SECTIONS
>          * The vectors and stubs are relocatable code, and the
>          * only thing that matters is their relative offsets
>          */
> -       __stubs_start = .;
>         .stubs : {
> +               __stubs_start = .;
>                 *(.stubs)
>         }
>         __stubs_end = .;

Yup, that fixed it!

bf353edc T _etext
bf353ee0 t __stubs_start
bf353ee0 T __stubs_start
bf353ee4 t vector_rst
bf353f00 t vector_irq

and my new print out:

     Stubs at c09ff000 :BF006F20 EF9F0000 EA000064 E320F000 etc...

Now that it is working on my XIP system, I will say that I'm also happy to see that extra junk in kallsyms.c and link-vmlinux.sh be removed. Those things also caused me some issues when I first started trying to get the XIP_KERNEL stuff back working.

Chris