So at least you can see what kernel you're booting if you die
before the kernel prints it mid-way through start_kernel().
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
There are two issues when we enable CONFIG_RELOCATABLE. The first is due
to the fact that phys_addr_t is now defined in linux/types.h. The second
is due to the fact that the DMA code changes expose memstart_addr to
prom_init.c
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
GCC 4.4.x looks to be adding support for generating out-of-line register
saves/restores based on:
http://gcc.gnu.org/ml/gcc-patches/2008-04/msg01678.html
This breaks the kernel if we enable CONFIG_CC_OPTIMIZE_FOR_SIZE. To fix
this we add the use the save/restore code from gcc and simplified it down
for our needs (integer only).
Additionally, we have to link this code into each module. The other
solution was to add EXPORT_SYMBOL() which meant going through the
trampoline which seemed nonsensical for these out-of-line routines.
Finally, we add some checks to prom_init_check.sh to ignore the
out-of-line save/restore functions.
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Since commit "85xx: Add support for relocatable kernel (and
booting at non-zero)" (37dd2badcf),
PHYSICAL_START is #defined as kernstart_addr if RELOCATABLE
and FLATMEM is enabled.
PHYSICAL_START is used in prom_init.c and so kernstart_addr
needs to be added to the list of allowed symbols that
prom_init.c can access.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Kumar Gala <galak@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
As BenH said the other day, it is an "accident" that prom_init.o is
linked with the rest of the kernel. The truth is a little more
subtle, prom_init isn't truly bootloader, it does access kernel data
in a few places.
What we can do is discourage people from adding new code that accesses
data outside of prom_init. And hence this patch; from the script:
# This script checks prom_init.o to see what external symbols it
# is using, if it finds symbols not in the whitelist it returns
# an error. The point of this is to discourage people from
# intentionally or accidentally adding new code to prom_init.c
# which has side effects on other parts of the kernel.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Michael Ellerman