From 549e8152de8039506f69c677a4546e5427aa6ae7 Mon Sep 17 00:00:00 2001 From: Paul Mackerras Date: Sat, 30 Aug 2008 11:43:47 +1000 Subject: powerpc: Make the 64-bit kernel as a position-independent executable This implements CONFIG_RELOCATABLE for 64-bit by making the kernel as a position-independent executable (PIE) when it is set. This involves processing the dynamic relocations in the image in the early stages of booting, even if the kernel is being run at the address it is linked at, since the linker does not necessarily fill in words in the image for which there are dynamic relocations. (In fact the linker does fill in such words for 64-bit executables, though not for 32-bit executables, so in principle we could avoid calling relocate() entirely when we're running a 64-bit kernel at the linked address.) The dynamic relocations are processed by a new function relocate(addr), where the addr parameter is the virtual address where the image will be run. In fact we call it twice; once before calling prom_init, and again when starting the main kernel. This means that reloc_offset() returns 0 in prom_init (since it has been relocated to the address it is running at), which necessitated a few adjustments. This also changes __va and __pa to use an equivalent definition that is simpler. With the relocatable kernel, PAGE_OFFSET and MEMORY_START are constants (for 64-bit) whereas PHYSICAL_START is a variable (and KERNELBASE ideally should be too, but isn't yet). With this, relocatable kernels still copy themselves down to physical address 0 and run there. Signed-off-by: Paul Mackerras --- arch/powerpc/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/Makefile') diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index c6be19e9ceae..4df38cbb4149 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -63,7 +63,9 @@ override CC += -m$(CONFIG_WORD_SIZE) override AR := GNUTARGET=elf$(CONFIG_WORD_SIZE)-powerpc $(AR) endif -LDFLAGS_vmlinux := -Bstatic +LDFLAGS_vmlinux-yy := -Bstatic +LDFLAGS_vmlinux-$(CONFIG_PPC64)$(CONFIG_RELOCATABLE) := -pie +LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-yy) CFLAGS-$(CONFIG_PPC64) := -mminimal-toc -mtraceback=none -mcall-aixdesc CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 -mmultiple -- cgit v1.2.3 From ce400c0102d8e1367266115ce6bc22333e5e3da6 Mon Sep 17 00:00:00 2001 From: Thiemo Seufer Date: Tue, 2 Sep 2008 00:23:02 +1000 Subject: powerpc: Enforce a non-spe kernel build even on broken compilers Those two are required on my fresh gcc 4.3.1. Signed-off-by: Thiemo Seufer Signed-off-by: Sebastian Siewior Signed-off-by: Paul Mackerras --- arch/powerpc/Makefile | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/powerpc/Makefile') diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 4df38cbb4149..24dd1a37f8fb 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -104,7 +104,10 @@ endif KBUILD_CFLAGS += $(call cc-option,-mno-altivec) # No SPE instruction when building kernel +# (We use all available options to help semi-broken compilers) KBUILD_CFLAGS += $(call cc-option,-mno-spe) +KBUILD_CFLAGS += $(call cc-option,-mspe=no) +KBUILD_CFLAGS += $(call cc-option,-mabi=no-spe) # Enable unit-at-a-time mode when possible. It shrinks the # kernel considerably. -- cgit v1.2.3