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authorShaohua Li <shaohua.li@intel.com>2009-01-08 22:29:49 -0500
committerIngo Molnar <mingo@elte.hu>2009-01-14 06:11:31 -0500
commita14a07b8018b714e03a39ff2180c66e307ef4238 (patch)
tree7c4b9249f862969b80b74e5e11e56480b0e3d15c /arch/ia64/Kconfig
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/Kconfig')
-rw-r--r--arch/ia64/Kconfig2
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index b992ba447c41..e20c1d45930a 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -21,6 +21,8 @@ config IA64
21 select HAVE_OPROFILE 21 select HAVE_OPROFILE
22 select HAVE_KPROBES 22 select HAVE_KPROBES
23 select HAVE_KRETPROBES 23 select HAVE_KRETPROBES
24 select HAVE_FTRACE_MCOUNT_RECORD
25 select HAVE_DYNAMIC_FTRACE if (!ITANIUM)
24 select HAVE_FUNCTION_TRACER 26 select HAVE_FUNCTION_TRACER
25 select HAVE_DMA_ATTRS 27 select HAVE_DMA_ATTRS
26 select HAVE_KVM 28 select HAVE_KVM