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

Chris Brandt Chris.Brandt at renesas.com
Wed Feb 3 05:33:13 PST 2016

On 2 Feb 2016, Chris Brandt wrote:
> I then applied the 3 patches and tried again and this time it booted
> up....almost.
> It looks like it makes it all the way up to when it is going to mount
> my rootfs, but then dies.

I did some debugging, and here's why I'm crashing.

If you look at my System.map file, you'll see that I've got 2 "__stubs_start" symbols.

One at 0x bf353edc, the other at 0x bf353ee0.

bf353edc T __stubs_start
bf353edc T _etext
bf353ee0 t __stubs_start
bf353ee4 t vector_rst
bf353f00 t vector_irq
bf353f80 t vector_dabt
bf354000 t vector_pabt
bf354080 t vector_und
bf354100 t vector_addrexcptn
bf354120 T vector_fiq
bf3541a0 T __stubs_end
bf3541a0 T __vectors_start
bf3541c0 t __mmap_switched
bf3541c0 T __vectors_end

So, when you get to early_trap_init(), it grabs the first __stubs_start for the memcpy:

	memcpy((void *)vectors + 0x1000, __stubs_start, __stubs_end - __stubs_start);

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.

So, I hacked the code and put an offset of 4 like this:

	memcpy((void *)vectors + 0x1000, __stubs_start+4, __stubs_end - (__stubs_start+4));

And sure enough it booted fine.

So, why are there 2 __stubs_start symbols???
I haven't figured that one out yet.

And, I'm assuming you guys don't have 2 __stubs_start symbols either, correct?


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