From: Peter Zijlstra <peterz@infradead.org>
To: x86@kernel.org
Cc: linux-kernel@vger.kernel.org, "H.J. Lu" <hjl.tools@gmail.com>,
ndesaulniers@google.com
Subject: [PATCH] x86: Use -mindirect-branch-cs-prefix for RETPOLINE builds
Date: Thu, 18 Nov 2021 19:54:21 +0100 [thread overview]
Message-ID: <20211118185421.GK174703@worktop.programming.kicks-ass.net> (raw)
In order to further enable commit:
bbe2df3f6b6d ("x86/alternative: Try inline spectre_v2=retpoline,amd")
add the new GCC flag -mindirect-branch-cs-prefix:
https://gcc.gnu.org/g:2196a681d7810ad8b227bf983f38ba716620545e
to RETPOLINE=y builds. This should allow fully inlining retpoline,amd
for GCC builds.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/Makefile b/Makefile
index 9e12c14ea0fb..5fd5b5f091ae 100644
--- a/Makefile
+++ b/Makefile
@@ -690,6 +690,7 @@ endif
ifdef CONFIG_CC_IS_GCC
RETPOLINE_CFLAGS := $(call cc-option,-mindirect-branch=thunk-extern -mindirect-branch-register)
+RETPOLINE_CFLAGS += $(call cc-option,-mindirect-branch-cs-prefix)
RETPOLINE_VDSO_CFLAGS := $(call cc-option,-mindirect-branch=thunk-inline -mindirect-branch-register)
endif
ifdef CONFIG_CC_IS_CLANG
next reply other threads:[~2021-11-18 18:54 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-18 18:54 Peter Zijlstra [this message]
2021-11-18 22:08 ` Nick Desaulniers
2021-11-19 15:11 ` Peter Zijlstra
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