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Commit 1194e838 authored by Andy Lutomirski's avatar Andy Lutomirski Committed by Greg Kroah-Hartman
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x86/vdso: Only enable vDSO retpolines when enabled and supported 



commit 4f166564014aba65ad6f15b612f6711fd0f117ee upstream.

When I fixed the vDSO build to use inline retpolines, I messed up
the Makefile logic and made it unconditional.  It should have
depended on CONFIG_RETPOLINE and on the availability of compiler
support.  This broke the build on some older compilers.

Reported-by: default avatar <nikola.ciprich@linuxbox.cz>
Signed-off-by: default avatarAndy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Rickard <matt@softrans.com.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: jason.vas.dias@gmail.com
Cc: stable@vger.kernel.org
Fixes: 2e549b2ee0e3 ("x86/vdso: Fix vDSO build if a retpoline is emitted")
Link: http://lkml.kernel.org/r/08a1f29f2c238dd1f493945e702a521f8a5aa3ae.1538540801.git.luto@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 64ff5747

arch/x86/entry/vdso/Makefile

+14 −2
Original line number Diff line number Diff line
@@ -74,7 +74,13 @@ $(obj)/vdso-image-%.c: $(obj)/vdso%.so.dbg $(obj)/vdso%.so $(obj)/vdso2c FORCE 
CFL := $(PROFILING) -mcmodel=small -fPIC -O2 -fasynchronous-unwind-tables -m64 \

       $(filter -g%,$(KBUILD_CFLAGS)) $(call cc-option, -fno-stack-protector) \

       -fno-omit-frame-pointer -foptimize-sibling-calls \

       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO $(RETPOLINE_VDSO_CFLAGS)

       -DDISABLE_BRANCH_PROFILING -DBUILD_VDSO



ifdef CONFIG_RETPOLINE

ifneq ($(RETPOLINE_VDSO_CFLAGS),)

  CFL += $(RETPOLINE_VDSO_CFLAGS)

endif

endif



$(vobjs): KBUILD_CFLAGS := $(filter-out $(GCC_PLUGINS_CFLAGS) $(RETPOLINE_CFLAGS),$(KBUILD_CFLAGS)) $(CFL)
@@ -153,7 +159,13 @@ KBUILD_CFLAGS_32 += $(call cc-option, -fno-stack-protector) 
KBUILD_CFLAGS_32 += $(call cc-option, -foptimize-sibling-calls)

KBUILD_CFLAGS_32 += -fno-omit-frame-pointer

KBUILD_CFLAGS_32 += -DDISABLE_BRANCH_PROFILING



ifdef CONFIG_RETPOLINE

ifneq ($(RETPOLINE_VDSO_CFLAGS),)

  KBUILD_CFLAGS_32 += $(RETPOLINE_VDSO_CFLAGS)

endif

endif



$(obj)/vdso32.so.dbg: KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)



$(obj)/vdso32.so.dbg: FORCE \