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authorPeter Zijlstra <peterz@infradead.org>2018-01-17 11:42:07 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-03-20 10:58:02 +0100
commite501ce957a786ecd076ea0cfb10b114e6e4d0f40 (patch)
tree93beb08eb9a78f81c80866baf25f7472df35b955 /arch/x86/Makefile
parentedc39c9b4589a4ce9a69273b5a27a1459c3423d4 (diff)
x86: Force asm-goto
We want to start using asm-goto to guarantee the absence of dynamic branches (and thus speculation). A primary prerequisite for this is of course that the compiler supports asm-goto. This effecively lifts the minimum GCC version to build an x86 kernel to gcc-4.5. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: torvalds@linux-foundation.org Link: https://lkml.kernel.org/r/20180319201327.GJ4043@hirez.programming.kicks-ass.net
Diffstat (limited to 'arch/x86/Makefile')
-rw-r--r--arch/x86/Makefile4
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 498c1b812300..d798e36d103c 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -181,6 +181,10 @@ ifdef CONFIG_FUNCTION_GRAPH_TRACER
endif
endif
+ifndef CC_HAVE_ASM_GOTO
+ $(error Compiler lacks asm-goto support.)
+endif
+
#
# Jump labels need '-maccumulate-outgoing-args' for gcc < 4.5.2 to prevent a
# GCC bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46226). There's no way