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[v17,7/7] x86/vdso: Insert endbr32/endbr64 to vDSO

Message ID 20201229213350.17010-8-yu-cheng.yu@intel.com (mailing list archive)
State New, archived
Headers show
Series Control-flow Enforcement: Indirect Branch Tracking | expand

Commit Message

Yu, Yu-cheng Dec. 29, 2020, 9:33 p.m. UTC
From: "H.J. Lu" <hjl.tools@gmail.com>

When Indirect Branch Tracking (IBT) is enabled, vDSO functions may be
called indirectly, and must have ENDBR32 or ENDBR64 as the first
instruction.  The compiler must support -fcf-protection=branch so that it
can be used to compile vDSO.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Signed-off-by: Yu-cheng Yu <yu-cheng.yu@intel.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
 arch/x86/entry/vdso/Makefile | 4 ++++
 1 file changed, 4 insertions(+)
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diff --git a/arch/x86/entry/vdso/Makefile b/arch/x86/entry/vdso/Makefile
index 02e3e42f380b..4d9225758a73 100644
--- a/arch/x86/entry/vdso/Makefile
+++ b/arch/x86/entry/vdso/Makefile
@@ -93,6 +93,10 @@  endif
+$(vobjs) $(vobjs32): KBUILD_CFLAGS += -fcf-protection=branch
 # vDSO code runs in userspace and -pg doesn't help with profiling anyway.