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| author | Nathan Lynch <nathan_lynch@mentor.com> | 2015-06-03 00:41:15 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2015-06-06 10:37:12 +0100 |
| commit | d2b30cd4b7223a96e606dfc8120626f66d81e091 (patch) | |
| tree | 7b2d8f0c1be0a5425587d532fd46a4178aeb4e15 /arch/arm | |
| parent | d33ce23b2160d26b27a47092da5d556b5b11a12a (diff) | |
| download | linux-d2b30cd4b7223a96e606dfc8120626f66d81e091.tar.bz2 | |
ARM: 8384/1: VDSO: force use of BFD linker
When using a toolchain with gold as the default linker, the VDSO build
fails:
VDSO arch/arm/vdso/vdso.so.raw
HOSTCC arch/arm/vdso/vdsomunge
MUNGE arch/arm/vdso/vdso.so.dbg
OBJCOPY arch/arm/vdso/vdso.so
BFD: arch/arm/vdso/vdso.so: Not enough room for program headers, try
linking with -N
For whatever reason, ld.gold is omitting an exidx program header that
ld.bfd emits, and even when I work around that, I don't get a working
VDSO.
For now, instead of supporting gold (which will fail to link the
kernel anyway since it does not implement --pic-veneer), direct the
compiler to use the traditional bfd linker. This is accomplished by
using -fuse-ld, which is implemented in GCC 4.8 and later.
Note: one limitation of this is that if the toolchain is configured
to use gold by default, and the bfd linker is not in $PATH, the VDSO
build will fail:
VDSO arch/arm/vdso/vdso.so.raw
collect2: fatal error: cannot find 'ld'
This will happen if CROSS_COMPILE begins with a path such as
/opt/bin/arm-linux-gnu- but /opt/bin is not in $PATH. This is
considered an acceptable corner-case limitation and is easily worked
around.
Additonal note: we use cc-option instead of cc-ldoption so that
-fuse-ld=bfd is placed in the command line if the compiler recognizes
the option. Using cc-ldoption results in an attempt to link, which
fails in the situation just described, causing -fuse-ld=bfd to be
omitted and gold to be used for the VDSO link, which is what we're
trying to prevent.
Reported-by: Stefan Agner <stefan@agner.ch>
Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/vdso/Makefile | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/arm/vdso/Makefile b/arch/arm/vdso/Makefile index 89182ad44ee8..9d259d94e429 100644 --- a/arch/arm/vdso/Makefile +++ b/arch/arm/vdso/Makefile @@ -14,6 +14,7 @@ VDSO_LDFLAGS += -Wl,-z,max-page-size=4096 -Wl,-z,common-page-size=4096 VDSO_LDFLAGS += -nostdlib -shared VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) VDSO_LDFLAGS += $(call cc-ldoption, -Wl$(comma)--build-id) +VDSO_LDFLAGS += $(call cc-option, -fuse-ld=bfd) obj-$(CONFIG_VDSO) += vdso.o extra-$(CONFIG_VDSO) += vdso.lds |