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Re: PATCH: Add sysdeps/x86_64/x32/tls.h


On Fri, May 11, 2012 at 1:55 PM, Roland McGrath <roland@hack.frob.com> wrote:
> That is OK but it would be better with a comment explaining why it's
> necessary. ?You only mentioned the need to use a register temporary
> because an indirect call would load too much from the pointer, but
> it also matters that the load of the argument register would load
> too much and have other stuff in the high bits rather than the
> zero-extension that you do here. ?The comment should mention that
> both issues matter.
>
>
> Thanks,
> Roland
>

This is I will commit.

Thanks.

-- 
H.J.
diff --git a/nptl/sysdeps/x86_64/x32/tls.h b/nptl/sysdeps/x86_64/x32/tls.h
new file mode 100644
index 0000000..6cc0ea7
--- /dev/null
+++ b/nptl/sysdeps/x86_64/x32/tls.h
@@ -0,0 +1,46 @@
+/* Definition for thread-local data handling.  nptl/x32 version.
+   Copyright (C) 2012 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _X32_TLS_H
+#define _X32_TLS_H	1
+
+#include <sysdeps/x86_64/tls.h>
+
+#ifndef __ASSEMBLER__
+
+/* X32 doesn't support 32-bit indirect call via memory.  Instead, we
+   load 32-bit address from memory into the lower 32bits of return
+   register, which will automatically zero-extend the uppper 32-bits
+   of return register.  We then do the indirect call via 64-bit return
+   register.  */
+# undef CALL_THREAD_FCT
+# define CALL_THREAD_FCT(descr) \
+  ({ void *__res;							      \
+     asm volatile ("movl %%fs:%P2, %%edi\n\t"				      \
+		   "movl %%fs:%P1, %k0\n\t"				      \
+		   "callq *%q0"						      \
+		   : "=a" (__res)					      \
+		   : "i" (offsetof (struct pthread, start_routine)),	      \
+		     "i" (offsetof (struct pthread, arg))		      \
+		   : "di", "si", "cx", "dx", "r8", "r9", "r10", "r11",	      \
+		     "memory", "cc");					      \
+     __res; })
+
+#endif /* __ASSEMBLER__ */
+
+#endif	/* x32/tls.h */

---


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