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| author | Anton Blanchard <anton@samba.org> | 2012-11-26 17:41:08 +0000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-01-10 17:00:31 +1100 |
| commit | 1fbe9cf2598dae3bd464d860bd89c67b1ff8682b (patch) | |
| tree | c07f1fe789777669466bc3077a5f0afa70cf83b6 /arch/powerpc/Makefile | |
| parent | 5827d4165ac608d7c26fa68701391e80824ee5c9 (diff) | |
| download | linux-1fbe9cf2598dae3bd464d860bd89c67b1ff8682b.tar.gz linux-1fbe9cf2598dae3bd464d860bd89c67b1ff8682b.tar.bz2 linux-1fbe9cf2598dae3bd464d860bd89c67b1ff8682b.zip | |
powerpc: Build kernel with -mcmodel=medium
Finally remove the two level TOC and build with -mcmodel=medium.
Unfortunately we can't build modules with -mcmodel=medium due to
the tricks the kernel module loader plays with percpu data:
# -mcmodel=medium breaks modules because it uses 32bit offsets from
# the TOC pointer to create pointers where possible. Pointers into the
# percpu data area are created by this method.
#
# The kernel module loader relocates the percpu data section from the
# original location (starting with 0xd...) to somewhere in the base
# kernel percpu data space (starting with 0xc...). We need a full
# 64bit relocation for this to work, hence -mcmodel=large.
On older kernels we fall back to the two level TOC (-mminimal-toc)
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/Makefile')
| -rw-r--r-- | arch/powerpc/Makefile | 19 |
1 files changed, 18 insertions, 1 deletions
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile index 78c2b024371a..31d8965e0847 100644 --- a/arch/powerpc/Makefile +++ b/arch/powerpc/Makefile @@ -67,7 +67,24 @@ LDFLAGS_vmlinux-y := -Bstatic LDFLAGS_vmlinux-$(CONFIG_RELOCATABLE) := -pie LDFLAGS_vmlinux := $(LDFLAGS_vmlinux-y) -CFLAGS-$(CONFIG_PPC64) := -mminimal-toc -mtraceback=no -mcall-aixdesc +ifeq ($(CONFIG_PPC64),y) +ifeq ($(call cc-option-yn,-mcmodel=medium),y) + # -mcmodel=medium breaks modules because it uses 32bit offsets from + # the TOC pointer to create pointers where possible. Pointers into the + # percpu data area are created by this method. + # + # The kernel module loader relocates the percpu data section from the + # original location (starting with 0xd...) to somewhere in the base + # kernel percpu data space (starting with 0xc...). We need a full + # 64bit relocation for this to work, hence -mcmodel=large. + KBUILD_CFLAGS_MODULE += -mcmodel=large +else + export NO_MINIMAL_TOC := -mno-minimal-toc +endif +endif + +CFLAGS-$(CONFIG_PPC64) := -mtraceback=no -mcall-aixdesc +CFLAGS-$(CONFIG_PPC64) += $(call cc-option,-mcmodel=medium,-mminimal-toc) CFLAGS-$(CONFIG_PPC32) := -ffixed-r2 -mmultiple CFLAGS-$(CONFIG_GENERIC_CPU) += $(call cc-option,-mtune=power7,-mtune=power4) |