On Wed, Jun 24, 2009 at 03:18:24PM -0700, Kaz Kylheku wrote:
> Aurelien Jarno wrote:
> > Hi all,
> >
> > I am still trying to get a Broadcom Swarm boot on a recent kernel. I
> > have made some progress, but I am now stuck on another problem.
> >
> > I am using a lmo 2.6.30 kernel, using the defconfig
>
> [ snip ]
>
> > | Kernel panic - not syncing: Attempted to kill init!
> > | Rebooting in 5 seconds..Passing control back to CFE...
>
> What kernel were you running prior to trying 30?
I am currently stuck with 2.6.18. I have tested a lot of kernels between
2.6.18 and 2.6.30, but they all have a different problem. Kernels 2.6.26
to 2.6.30 suffer from a similar problem, though from some versions it
hangs instead of panicking.
> When I migrated from 2.6.17 to 2.6.26, on a Broadcom
> 1480 based board, I discovered that there is some kind
> of instruction cache problem, which causes userland to
> fetch garbage instead of code from its mmap-ped executables.
> I could not get init to execute successfully.
>
> Sorry, I can no longer remember whether this problem was
> SMP specific or not (like what you're experiencing);
> it might have been.
>
> At some point in the kernel history, Ralfie decided that
> the flush_icache_page function is unnecessary and
> turned it into a MIPS-wide noop. But the SB1 core, which has
> a VIVT instruction cache, it appears that there
> is some kind of issue whereby when it
> is handling a fault for a not-present virtual page,
> it somehow ends up with bad data in the instruction
> cache---perhaps an inconsistent state due to not having
> been able to complete the fetch, but having initiated
> a cache update on the expectation that the fetch
> will complete. It seems that the the fault handler
> is expected to do a flush.
>
> Anyway, see if you can work this patch (based on 2.6.26)
> into your kernel, and report whether it makes any difference.
I have applied the patch on 2.6.30 after a few changes, and it works!!!
Thanks a lot!
> Index: include/asm-mips/cacheflush.h
> ===================================================================
> --- include/asm-mips/cacheflush.h (revision 2677)
> +++ include/asm-mips/cacheflush.h (revision 2678)
> @@ -37,6 +37,7 @@
> unsigned long start, unsigned long end);
> extern void (*flush_cache_page)(struct vm_area_struct *vma, unsigned
> long page, unsigned long pfn);
> extern void __flush_dcache_page(struct page *page);
> +extern void __flush_icache_page(struct vm_area_struct *vma, struct page
> *page);
>
> static inline void flush_dcache_page(struct page *page)
> {
> @@ -57,11 +58,6 @@
> __flush_anon_page(page, vmaddr);
> }
>
> -static inline void flush_icache_page(struct vm_area_struct *vma,
> - struct page *page)
> -{
> -}
> -
> extern void (*flush_icache_range)(unsigned long start, unsigned long
> end);
>
> extern void (*__flush_cache_vmap)(void);
> @@ -93,6 +89,13 @@
> extern void (*local_flush_data_cache_page)(void * addr);
> extern void (*flush_data_cache_page)(unsigned long addr);
>
> +static inline void flush_icache_page(struct vm_area_struct *vma,
> + struct page *page)
> +{
> + __flush_icache_page(vma, page);
> +}
> +
> +
> /*
> * This flag is used to indicate that the page pointed to by a pte
> * is dirty and requires cleaning before returning it to the user.
> Index: arch/mips/mm/cache.c
> ===================================================================
> --- arch/mips/mm/cache.c (revision 2677)
> +++ arch/mips/mm/cache.c (revision 2678)
> @@ -93,6 +93,14 @@
>
> EXPORT_SYMBOL(__flush_dcache_page);
>
> +void __flush_icache_page(struct vm_area_struct *vma, struct page *page)
> +{
> + if (vma->vm_flags & VM_EXEC)
> + flush_icache_range((unsigned long) page_address(page),
> PAGE_SIZE);
> +}
> +
> +EXPORT_SYMBOL(__flush_icache_page);
> +
> void __flush_anon_page(struct page *page, unsigned long vmaddr)
> {
> unsigned long addr = (unsigned long) page_address(page);
>
>
--
Aurelien Jarno GPG: 1024D/F1BCDB73
aurelien@xxxxxxxxxxx http://www.aurel32.net
