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authorNicholas Piggin <npiggin@gmail.com>2017-05-12 01:56:52 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2017-05-30 14:59:51 +1000
commitefe0160cfd40a99c052a00e174787c1f4158a9cd (patch)
tree61f8f8ad39191e2bbc1980e2a493b63ddc79f397
parentcde9f2f4207f769c0f8f0f53a431348ca6f3c182 (diff)
downloadblackbird-op-linux-efe0160cfd40a99c052a00e174787c1f4158a9cd.tar.gz
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powerpc/64: Linker on-demand sfpr functions for modules
For final link, the powerpc64 linker generates fpr save/restore functions on-demand, placing them in the .sfpr section. Starting with binutils 2.25, these can be provided for non-final links with --save-restore-funcs. Use that where possible for module links. This saves about 200 bytes per module (~60kB) on powernv defconfig build. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
-rw-r--r--arch/powerpc/Makefile10
-rw-r--r--arch/powerpc/lib/Makefile13
2 files changed, 18 insertions, 5 deletions
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 3e0f0e1fadef..eaa1865e4a8d 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -189,7 +189,17 @@ else
CHECKFLAGS += -D__LITTLE_ENDIAN__
endif
+ifdef CONFIG_PPC32
KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
+else
+ifeq ($(call ld-ifversion, -ge, 225000000, y),y)
+# Have the linker provide sfpr if possible.
+# There is a corresponding test in arch/powerpc/lib/Makefile
+KBUILD_LDFLAGS_MODULE += --save-restore-funcs
+else
+KBUILD_LDFLAGS_MODULE += arch/powerpc/lib/crtsavres.o
+endif
+endif
ifeq ($(CONFIG_476FPE_ERR46),y)
KBUILD_LDFLAGS_MODULE += --ppc476-workaround \
diff --git a/arch/powerpc/lib/Makefile b/arch/powerpc/lib/Makefile
index 0ca405a27ac1..2c56f4636c2b 100644
--- a/arch/powerpc/lib/Makefile
+++ b/arch/powerpc/lib/Makefile
@@ -11,12 +11,15 @@ CFLAGS_REMOVE_feature-fixups.o = $(CC_FLAGS_FTRACE)
obj-y += string.o alloc.o code-patching.o feature-fixups.o
-# 64-bit linker creates .sfpr on demand for final link (vmlinux),
-# so it is only needed for modules.
-obj-$(CONFIG_PPC32) += crtsavres.o
-extra-$(CONFIG_PPC64) += crtsavres.o
+obj-$(CONFIG_PPC32) += div64.o copy_32.o crtsavres.o
-obj-$(CONFIG_PPC32) += div64.o copy_32.o
+# See corresponding test in arch/powerpc/Makefile
+# 64-bit linker creates .sfpr on demand for final link (vmlinux),
+# so it is only needed for modules, and only for older linkers which
+# do not support --save-restore-funcs
+ifeq ($(call ld-ifversion, -lt, 225000000, y),y)
+extra-$(CONFIG_PPC64) += crtsavres.o
+endif
obj64-y += copypage_64.o copyuser_64.o mem_64.o hweight_64.o \
copyuser_power7.o string_64.o copypage_power7.o memcpy_power7.o \
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