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authorShaohua Li <shaohua.li@intel.com>2009-01-09 11:29:49 +0800
committerIngo Molnar <mingo@elte.hu>2009-01-14 12:11:31 +0100
commita14a07b8018b714e03a39ff2180c66e307ef4238 (patch)
tree7c4b9249f862969b80b74e5e11e56480b0e3d15c /arch/ia64/include/asm/ftrace.h
parentd3e75ff14bc1453c4762428395aac9953a023efc (diff)
ftrace, ia64: IA64 dynamic ftrace support
IA64 dynamic ftrace support. The original _mcount stub for each function is like: alloc r40=ar.pfs,12,8,0 mov r43=r0;; mov r42=b0 mov r41=r1 nop.i 0x0 br.call.sptk.many b0 = _mcount;; The patch convert it to below for nop: [MII] nop.m 0x0 mov r3=ip nop.i 0x0 [MLX] nop.m 0x0 nop.x 0x0;; This isn't completely nop, as there is one instuction 'mov r3=ip', but it should be light and harmless for code follow it. And below is for call [MII] nop.m 0x0 mov r3=ip nop.i 0x0 [MLX] nop.m 0x0 brl.many .;; In this way, only one instruction is changed to convert code between nop and call. This should meet dyn-ftrace's requirement. But this requires CPU support brl instruction, so dyn-ftrace isn't supported for old Itanium system. Assume there are quite few such old system running. Signed-off-by: Shaohua Li <shaohua.li@intel.com> Signed-off-by: Steven Rostedt <srostedt@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/ia64/include/asm/ftrace.h')
-rw-r--r--arch/ia64/include/asm/ftrace.h13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/ia64/include/asm/ftrace.h b/arch/ia64/include/asm/ftrace.h
index 48694b3ba5a..d20db3c2a65 100644
--- a/arch/ia64/include/asm/ftrace.h
+++ b/arch/ia64/include/asm/ftrace.h
@@ -8,6 +8,19 @@
extern void _mcount(unsigned long pfs, unsigned long r1, unsigned long b0, unsigned long r0);
#define mcount _mcount
+#include <asm/kprobes.h>
+/* In IA64, MCOUNT_ADDR is set in link time, so it's not a constant at compile time */
+#define MCOUNT_ADDR (((struct fnptr *)mcount)->ip)
+#define FTRACE_ADDR (((struct fnptr *)ftrace_caller)->ip)
+
+static inline unsigned long ftrace_call_adjust(unsigned long addr)
+{
+ /* second bundle, insn 2 */
+ return addr - 0x12;
+}
+
+struct dyn_arch_ftrace {
+};
#endif
#endif /* CONFIG_FUNCTION_TRACER */