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authorNicholas Piggin <npiggin@gmail.com>2017-06-19 18:52:05 +0300
committerMasahiro Yamada <yamada.masahiro@socionext.com>2017-06-30 03:03:03 +0300
commit3a166fc2d4ef7a6b7e440271ee6bd1799c066605 (patch)
treef0c4ea695592ad123e22c85d649ec917796a6652
parent9a6cfca4f4130444cb02536a4fdf7b6e285c713e (diff)
downloadlinux-3a166fc2d4ef7a6b7e440271ee6bd1799c066605.tar.xz
kbuild: handle libs-y archives separately from built-in.o archives
The thin archives build currently puts all lib.a and built-in.o files together and links them with --whole-archive. This works because thin archives can recursively refer to thin archives. However some architectures include libgcc.a, which may not be a thin archive, or it may not be constructed with the "P" option, in which case its contents do not get linked correctly. So don't pull .a libs into the root built-in.o archive. These libs should already have symbol tables and indexes built, so they can be direct linker inputs. Move them out of the --whole-archive option, which restore the conditional linking behaviour of lib.a to thin archives builds. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
-rw-r--r--Documentation/kbuild/kbuild.txt8
-rw-r--r--Makefile8
-rwxr-xr-xscripts/link-vmlinux.sh45
3 files changed, 46 insertions, 15 deletions
diff --git a/Documentation/kbuild/kbuild.txt b/Documentation/kbuild/kbuild.txt
index 0ff6a466a05b..ac2363ea05c5 100644
--- a/Documentation/kbuild/kbuild.txt
+++ b/Documentation/kbuild/kbuild.txt
@@ -236,5 +236,9 @@ Files specified with KBUILD_VMLINUX_INIT are linked first.
KBUILD_VMLINUX_MAIN
--------------------------------------------------
All object files for the main part of vmlinux.
-KBUILD_VMLINUX_INIT and KBUILD_VMLINUX_MAIN together specify
-all the object files used to link vmlinux.
+
+KBUILD_VMLINUX_LIBS
+--------------------------------------------------
+All .a "lib" files for vmlinux.
+KBUILD_VMLINUX_INIT, KBUILD_VMLINUX_MAIN, and KBUILD_VMLINUX_LIBS together
+specify all the object files used to link vmlinux.
diff --git a/Makefile b/Makefile
index 853ae9179af9..1177775fa410 100644
--- a/Makefile
+++ b/Makefile
@@ -952,19 +952,19 @@ core-y := $(patsubst %/, %/built-in.o, $(core-y))
drivers-y := $(patsubst %/, %/built-in.o, $(drivers-y))
net-y := $(patsubst %/, %/built-in.o, $(net-y))
libs-y1 := $(patsubst %/, %/lib.a, $(libs-y))
-libs-y2 := $(patsubst %/, %/built-in.o, $(libs-y))
-libs-y := $(libs-y1) $(libs-y2)
+libs-y2 := $(filter-out %.a, $(patsubst %/, %/built-in.o, $(libs-y)))
virt-y := $(patsubst %/, %/built-in.o, $(virt-y))
# Externally visible symbols (used by link-vmlinux.sh)
export KBUILD_VMLINUX_INIT := $(head-y) $(init-y)
-export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y) $(drivers-y) $(net-y) $(virt-y)
+export KBUILD_VMLINUX_MAIN := $(core-y) $(libs-y2) $(drivers-y) $(net-y) $(virt-y)
+export KBUILD_VMLINUX_LIBS := $(libs-y1)
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
export LDFLAGS_vmlinux
# used by scripts/pacmage/Makefile
export KBUILD_ALLDIRS := $(sort $(filter-out arch/%,$(vmlinux-alldirs)) arch Documentation include samples scripts tools)
-vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN)
+vmlinux-deps := $(KBUILD_LDS) $(KBUILD_VMLINUX_INIT) $(KBUILD_VMLINUX_MAIN) $(KBUILD_VMLINUX_LIBS)
# Include targets which we want to execute sequentially if the rest of the
# kernel build went well. If CONFIG_TRIM_UNUSED_KSYMS is set, this might be
diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh
index 72a0aa627c56..e7b7eee31538 100755
--- a/scripts/link-vmlinux.sh
+++ b/scripts/link-vmlinux.sh
@@ -3,9 +3,12 @@
# link vmlinux
#
# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
-# $(KBUILD_VMLINUX_MAIN). Most are built-in.o files from top-level directories
-# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
-# Ordering when linking is important, and $(KBUILD_VMLINUX_INIT) must be first.
+# $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.o files
+# from top-level directories in the kernel tree, others are specified in
+# arch/$(ARCH)/Makefile. Ordering when linking is important, and
+# $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
+# which are linked conditionally (not within --whole-archive), and do not
+# require symbol indexes added.
#
# vmlinux
# ^
@@ -16,6 +19,9 @@
# +--< $(KBUILD_VMLINUX_MAIN)
# | +--< drivers/built-in.o mm/built-in.o + more
# |
+# +--< $(KBUILD_VMLINUX_LIBS)
+# | +--< lib/lib.a + more
+# |
# +-< ${kallsymso} (see description in KALLSYMS section)
#
# vmlinux version (uname -v) cannot be updated during normal
@@ -37,9 +43,10 @@ info()
fi
}
-# Thin archive build here makes a final archive with
-# symbol table and indexes from vmlinux objects, which can be
-# used as input to linker.
+# Thin archive build here makes a final archive with symbol table and indexes
+# from vmlinux objects INIT and MAIN, which can be used as input to linker.
+# KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
+# added.
#
# Traditional incremental style of link does not require this step
#
@@ -63,11 +70,17 @@ modpost_link()
local objects
if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
- objects="--whole-archive built-in.o --no-whole-archive"
+ objects="--whole-archive \
+ built-in.o \
+ --no-whole-archive \
+ --start-group \
+ ${KBUILD_VMLINUX_LIBS} \
+ --end-group"
else
objects="${KBUILD_VMLINUX_INIT} \
--start-group \
${KBUILD_VMLINUX_MAIN} \
+ ${KBUILD_VMLINUX_LIBS} \
--end-group"
fi
${LD} ${LDFLAGS} -r -o ${1} ${objects}
@@ -83,11 +96,18 @@ vmlinux_link()
if [ "${SRCARCH}" != "um" ]; then
if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
- objects="--whole-archive built-in.o ${1} --no-whole-archive"
+ objects="--whole-archive \
+ built-in.o \
+ --no-whole-archive \
+ --start-group \
+ ${KBUILD_VMLINUX_LIBS} \
+ --end-group \
+ ${1}"
else
objects="${KBUILD_VMLINUX_INIT} \
--start-group \
${KBUILD_VMLINUX_MAIN} \
+ ${KBUILD_VMLINUX_LIBS} \
--end-group \
${1}"
fi
@@ -96,11 +116,18 @@ vmlinux_link()
-T ${lds} ${objects}
else
if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
- objects="-Wl,--whole-archive built-in.o ${1} -Wl,--no-whole-archive"
+ objects="-Wl,--whole-archive \
+ built-in.o \
+ -Wl,--no-whole-archive \
+ -Wl,--start-group \
+ ${KBUILD_VMLINUX_LIBS} \
+ -Wl,--end-group \
+ ${1}"
else
objects="${KBUILD_VMLINUX_INIT} \
-Wl,--start-group \
${KBUILD_VMLINUX_MAIN} \
+ ${KBUILD_VMLINUX_LIBS} \
-Wl,--end-group \
${1}"
fi