VDSO text is fixed-up during init so it can't be const,
but it can be read-only after init.
Do the same as x86 in commit 018ef8dcf3 ("x86/vdso: Mark the vDSO
code read-only after init") and arm in commit 11bf9b8658 ("ARM/vdso:
Mark the vDSO code read-only after init"), move it into
ro_after_init section.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/e9892d288b646cbdfeef0b2b73edbaf6d3c6cabe.1734174500.git.christophe.leroy@csgroup.eu
vgettimeofday.o is unnecessarily rebuilt. Adding it to 'targets' is not
enough to fix the issue. Kbuild is correctly rebuilding it because the
command line is changed.
PowerPC builds each vdso directory twice; first in vdso_prepare to
generate vdso{32,64}-offsets.h, second as part of the ordinary build
process to embed vdso{32,64}.so.dbg into the kernel.
The problem shows up when CONFIG_PPC_WERROR=y due to the following line
in arch/powerpc/Kbuild:
subdir-ccflags-$(CONFIG_PPC_WERROR) := -Werror
In the preparation stage, Kbuild directly visits the vdso directories,
hence it does not inherit subdir-ccflags-y. In the second descend,
Kbuild adds -Werror, which results in the command line flipping
with/without -Werror.
It implies a potential danger; if a more critical flag that would impact
the resulted vdso, the offsets recorded in the headers might be different
from real offsets in the embedded vdso images.
Removing the unneeded second descend solves the problem.
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/linuxppc-dev/87tuslxhry.fsf@mpe.ellerman.id.au/
Link: https://lore.kernel.org/r/20201223171142.707053-1-masahiroy@kernel.org
2021-01-30 22:23:42 +11:00
Renamed from arch/powerpc/kernel/vdso64/vdso64_wrapper.S (Browse further)
