Re: [PATCH] Linux Kernel Markers 0.13 for 2.6.17

From: Jeremy Fitzhardinge
Date: Mon Sep 25 2006 - 20:07:48 EST


Mathieu Desnoyers wrote:
+/* Note : max 256 bytes between over_label and near_jump */
+#define MARK_JUMP(name, format, args...) \
+ do { \
+ asm volatile( ".section .markers, \"a\";\n\t" \
+ ".long 0f, 1f, 2f;\n\t" \
+ ".previous;\n\t" \
+ ".align 16;\n\t" \
+ ".byte 0xeb;\n\t" \
+ "0:\n\t" \
+ ".byte 2f-1f;\n\t" \
+ "1:\n\t" \
+ : "+m" (__marker_sequencer) : ); \
+ MARK_CALL(name, format, ## args); \
+ asm volatile ( "2:\n\t" : "+m" (__marker_sequencer) : ); \

Unfortunately this doesn't work either. The two asms are ordered with respect to each other, but there's nothing to 1) stop the MARK_CALL from being moved out between them, 2) something else being moved in between them. I don't really see a way out of this without implementing the whole call in assembler as well, which is a big pain.

J
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