v3.11-rc4: OMAP1/Amstrad Delta (E3) crash

[Aaro Koskinen]

Hi,

On Thu, Aug 08, 2013 at 12:08:56AM +0100, Russell King - ARM Linux wrote:
> On Wed, Aug 07, 2013 at 10:05:21PM +0300, Aaro Koskinen wrote:
> > On Wed, Aug 07, 2013 at 02:26:09AM +0300, Aaro Koskinen wrote:
> > > I get the following on Amstrad Delta (E3) when booting unpatched
> > > v3.11-rc4. The kernel config is after the crash.
> > 
> > This is regression introduced between -rc3 and -rc4. According to the
> > git bisect, the first bad commit is:
> > 
> > 	commit e39e3f3ebfef03450cf7bfa7a974a8c61f7980c8
> > 	Author: Russell King <rmk+kernel at arm.linux.org.uk>
> > 	Date:   Tue Jul 9 01:03:17 2013 +0100
> > 
> > 	    ARM: update FIQ support for relocation of vectors
> > 
> > If I revert the commit from v3.11-rc4, the board boots fine.
> > 
> > A.
> > 
> > > Uncompressing Linux... done, booting the kernel.
> > > [    0.000000] Booting Linux on physical CPU 0x0
> > > [    0.000000] Initializing cgroup subsys cpu
> > > [    0.000000] Linux version 3.11.0-rc4-e3 (aaro at blackmetal) (gcc version 4.7.3 (GCC) ) #4 PREEMPT Wed Aug 7 02:03:27 EEST 2013
> > > [    0.000000] bootconsole [earlycon0] enabled
> > > [    0.000000] OMAP1510
> > > [    0.000000]  revision 2 handled as 15xx id: bc058c9b93111a16
> 
> Hmm, so ARM925T which is VIVT...
> 
> > > [    0.238868] Installing fiq handler from c001b110, length 0x164
> > > [    0.245750] Unable to handle kernel paging request at virtual address ffff1224
> 
> In one way, that's good news - that's public independent proof that the
> code associated with the vectors is well protected from kernel writes. :)
> 
> Can you try this (untested) patch please?  We need to write into this
> page via the page's alias, rather than directly to it.  Thanks.

That seems to work - the board boots fine to shell as before. Feel free
to add Reported-by: or Tested-by: from me to the patch.

Thanks,

A.

>  arch/arm/kernel/fiq.c |    8 ++------
>  1 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/arm/kernel/fiq.c b/arch/arm/kernel/fiq.c
> index 25442f4..fc79202 100644
> --- a/arch/arm/kernel/fiq.c
> +++ b/arch/arm/kernel/fiq.c
> @@ -84,17 +84,13 @@ int show_fiq_list(struct seq_file *p, int prec)
>  
>  void set_fiq_handler(void *start, unsigned int length)
>  {
> -#if defined(CONFIG_CPU_USE_DOMAINS)
> -	void *base = (void *)0xffff0000;
> -#else
>  	void *base = vectors_page;
> -#endif
>  	unsigned offset = FIQ_OFFSET;
>  
>  	memcpy(base + offset, start, length);
> +	if (!cache_is_vipt_nonaliasing())
> +		flush_icache_range(base + offset, offset + length);
>  	flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length);
> -	if (!vectors_high())
> -		flush_icache_range(offset, offset + length);
>  }
>  
>  int claim_fiq(struct fiq_handler *f)
> 
> 
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