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authorSuzuki Poulose <suzuki@in.ibm.com>2011-12-14 22:59:24 +0000
committerJosh Boyer <jwboyer@gmail.com>2011-12-20 10:21:57 -0500
commit26ecb6c44bb33afc62905ba01b636dde70fc2dc6 (patch)
tree1e2a12510dcc81b40705ed04a1f4e1470856b041 /arch/powerpc/Kconfig
parent368ff8f14d6ed8e9fd3b7c2156f2607719bf5a7a (diff)
powerpc/44x: Enable CONFIG_RELOCATABLE for PPC44x
The following patch adds relocatable kernel support - based on processing of dynamic relocations - for PPC44x kernel. We find the runtime address of _stext and relocate ourselves based on the following calculation. virtual_base = ALIGN(KERNELBASE,256M) + MODULO(_stext.run,256M) relocate() is called with the Effective Virtual Base Address (as shown below) | Phys. Addr| Virt. Addr | Page (256M) |------------------------| Boundary | | | | | | | | | Kernel Load |___________|_ __ _ _ _ _|<- Effective Addr(_stext)| | ^ |Virt. Base Addr | | | | | | | | | |reloc_offset| | | | | | | | | | |______v_____|<-(KERNELBASE)%256M | | | | | | | | | Page(256M) |-----------|------------| Boundary | | | The virt_phys_offset is updated accordingly, i.e, virt_phys_offset = effective. kernel virt base - kernstart_addr I have tested the patches on 440x platforms only. However this should work fine for PPC_47x also, as we only depend on the runtime address and the current TLB XLAT entry for the startup code, which is available in r25. I don't have access to a 47x board yet. So, it would be great if somebody could test this on 47x. Signed-off-by: Suzuki K. Poulose <suzuki@in.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Tony Breeds <tony@bakeyournoodle.com> Cc: Josh Boyer <jwboyer@gmail.com> Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org> Signed-off-by: Josh Boyer <jwboyer@gmail.com>
Diffstat (limited to 'arch/powerpc/Kconfig')
-rw-r--r--arch/powerpc/Kconfig2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 2ad5ea82782..1703509649b 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -851,7 +851,7 @@ config DYNAMIC_MEMSTART
config RELOCATABLE
bool "Build a relocatable kernel (EXPERIMENTAL)"
- depends on EXPERIMENTAL && ADVANCED_OPTIONS && FLATMEM
+ depends on EXPERIMENTAL && ADVANCED_OPTIONS && FLATMEM && 44x
select NONSTATIC_KERNEL
help
This builds a kernel image that is capable of running at the