21 lines
913 B
Diff
21 lines
913 B
Diff
For i?86 negative offsets to %fs segment accesses cause a hypervisor
|
|
trap for Xen. Avoid this by making accesses indirect.
|
|
|
|
??? Note that similar to the behavior on SLE11 this only affects
|
|
the compiler built on %ix86, not that on x86_64, even with -m32.
|
|
|
|
Index: gcc/config/i386/linux.h
|
|
===================================================================
|
|
--- gcc/config/i386/linux.h.orig 2015-12-17 15:07:37.785650062 +0100
|
|
+++ gcc/config/i386/linux.h 2015-12-17 15:08:06.393983290 +0100
|
|
@@ -24,3 +24,9 @@ along with GCC; see the file COPYING3.
|
|
|
|
#undef MUSL_DYNAMIC_LINKER
|
|
#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
|
|
+
|
|
+/* This slows down Xen, so take a very small general performance hit
|
|
+ for not accessing the %fs segment with negative offsets by making
|
|
+ GCC not emit direct accesses to %fs at all. */
|
|
+#undef TARGET_TLS_DIRECT_SEG_REFS_DEFAULT
|
|
+#define TARGET_TLS_DIRECT_SEG_REFS_DEFAULT 0
|