From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: linux-arm-kernel@lists.infradead.org
Cc: Geoff Levand <geoff@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will@kernel.org>, Ard Biesheuvel <ardb@kernel.org>
Subject: [PATCH] arm64: vdso: Fix ldflags for -Bsymbolic
Date: Tue, 28 Apr 2020 16:08:54 +0100 [thread overview]
Message-ID: <20200428150854.33130-1-vincenzo.frascino@arm.com> (raw)
The vDSO library adds -Bsymbolic to the ldflags because when the shared
library is built it adds a flag in the dynamic section of the binary
called DT_SYMBOLIC which alters the dynamic linker's symbol resolution
algorithm to search for references for a symbol inside the library first
and then into the executable.
In the current implementation of the library for arm64 the flag has been
wrongly added to VDSO_LDFLAGS which is never used.
Restore the correct behavior adding the flag to ldflags.
Note: -Bsymbolic has been added for consistency with arm and future
proof.
Fixes: 28b1a824a4f44 ("arm64: vdso: Substitute gettimeofday() with C implementation")
Cc: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Reported-by: Geoff Levand <geoff@infradead.org>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
---
arch/arm64/kernel/vdso/Makefile | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile
index abb3347a925b..6ba222ad8cc2 100644
--- a/arch/arm64/kernel/vdso/Makefile
+++ b/arch/arm64/kernel/vdso/Makefile
@@ -17,14 +17,17 @@ obj-vdso := vgettimeofday.o note.o sigreturn.o
targets := $(obj-vdso) vdso.so vdso.so.dbg
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
+# -Bsymbolic has been added for consistency with arm and future proof.
+# It adds a flag in the dynamic section of the binary called DT_SYMBOLIC
+# which alters the dynamic linker's symbol resolution algorithm to search
+# for references for a symbol inside the library first and then into the
+# executable.
ldflags-y := -shared -nostdlib -soname=linux-vdso.so.1 --hash-style=sysv \
- --build-id -n -T
+ -Bsymbolic --build-id -n -T
ccflags-y := -fno-common -fno-builtin -fno-stack-protector -ffixed-x18
ccflags-y += -DDISABLE_BRANCH_PROFILING
-VDSO_LDFLAGS := -Bsymbolic
-
CFLAGS_REMOVE_vgettimeofday.o = $(CC_FLAGS_FTRACE) -Os
KBUILD_CFLAGS += $(DISABLE_LTO)
KASAN_SANITIZE := n
--
2.25.2
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next reply other threads:[~2020-04-28 15:09 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-28 15:08 Vincenzo Frascino [this message]
2020-04-28 16:25 ` [PATCH] arm64: vdso: Fix ldflags for -Bsymbolic Will Deacon
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