forked from pool/gcc12
67536f9052
Rev devel:gcc/1 Md5 ae463db7c2b11a8484bb26da6735cffb 2022-01-13 12:39:29 rguenther 946019
21 lines
913 B
Diff
21 lines
913 B
Diff
For i?86 negative offsets to %fs segment accesses cause a hypervisor
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trap for Xen. Avoid this by making accesses indirect.
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??? Note that similar to the behavior on SLE11 this only affects
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the compiler built on %ix86, not that on x86_64, even with -m32.
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Index: gcc/config/i386/linux.h
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===================================================================
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--- gcc/config/i386/linux.h.orig 2015-12-17 15:07:37.785650062 +0100
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+++ gcc/config/i386/linux.h 2015-12-17 15:08:06.393983290 +0100
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@@ -24,3 +24,9 @@ along with GCC; see the file COPYING3.
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#undef MUSL_DYNAMIC_LINKER
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#define MUSL_DYNAMIC_LINKER "/lib/ld-musl-i386.so.1"
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+
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+/* This slows down Xen, so take a very small general performance hit
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+ for not accessing the %fs segment with negative offsets by making
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+ GCC not emit direct accesses to %fs at all. */
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+#undef TARGET_TLS_DIRECT_SEG_REFS_DEFAULT
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+#define TARGET_TLS_DIRECT_SEG_REFS_DEFAULT 0
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