From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <4B6E8167.6010907@domain.hid>
Date: Sun, 07 Feb 2010 10:01:27 +0100
From: Roland Stigge <stigge@domain.hid>
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Subject: [Xenomai-core] Xenomai in Debian
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To: Xenomai core <Xenomai-core@domain.hid>
Cc: Jan Kiszka <jan.kiszka@domain.hid>

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Hi,

I'm just working on the Xenomai 2.5.1 Debian package and encountered 
non-PIC code (evil! ;-) in the shared libraries (skins libraries).

You can see it with e.g.

$ readelf -d src/skins/native/.libs/libnative.so.3.0.0

The "TEXTREL" tag indicates non-PIC code.

$ scanelf -qT src/skins/native/.libs/libnative.so.3.0.0

Shows the function and code offset of the relocation.

With

$ objdump -d src/skins/native/.libs/libnative.so.3.0.0

I found the actual location of the relocation.

I prepared a patch (attached) that fixes it: First, the relocation 
itself by letting GCC create the address in PIC style. Second, "extern 
inline" looks a bit counterintuitive at first, but according to the GCC 
manual, it seems to be what we want (macro behaviour).

Thanks Jan for reminding me!

bye,
   Roland

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--- xenomai-2.5.1.orig/include/asm-x86/syscall.h
+++ xenomai-2.5.1/include/asm-x86/syscall.h
@@ -161,9 +161,11 @@
      ".endif\n\t"
      ".endm\n\t");
 
-static inline void __xn_get_eip(void **dest)
+__attribute__((always_inline))
+extern inline void __xn_get_eip(void **dest)
 {
-        asm volatile("movl $1f, %0; 1:": "=m"(*dest));
+addr:
+	*dest = &&addr;
 }
 
 static inline void __xn_get_ebp(void **dest)

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