[U-Boot] MIPS cpu has problem detecting CFI

[Andrew Dyer]

On Mon, Oct 12, 2009 at 5:11 PM, Andrew Dyer <amdyer at gmail.com> wrote:
> On Mon, Oct 12, 2009 at 10:10 AM,  <myuboot at fastmail.fm> wrote:
>> Thanks for 1) and 2).
>> For 3), both results show GP register is modified.
>> the result of ${CROSS_COMPILE}objdump --source cpu.o is:
>>
>> void flush_cache(ulong start_addr, ulong size)
>> {
>>  7c:   3c1c0000        lui     gp,0x0
>>  80:   279c0000        addiu   gp,gp,0
>>  84:   0399e021        addu    gp,gp,t9
>
> It looks like the code expects t9 to have the gp value.  I need to get
> my setup up to -current and do a build test with eldk to help much
> more (we don't do much mips anymore here, so my setup is a bit behind
> the times).

whoops - the above is wrong - t9 is supposed to have the starting
address of the function in it.  The 0 constants in the preceding two
instructions are supposed to be setup by the linker to give an offset
to the correct value of $gp for this function.

http://books.google.com/books?id=kk8G2gK4Tw8C&pg=PA413&lpg=PA413&dq=mips+%24gp+%24t9+register&source=bl&ots=cZ4SkaNyWt&sig=COnSNFcUHtReMS9vVMere9DFzQk&hl=en&ei=G6vTSuXFA42sMOf4xZQD&sa=X&oi=book_result&ct=result&resnum=4&ved=0CBUQ6AEwAw#v=onepage&q=mips%20%24gp%20%24t9%20register&f=false

was where I found this.