(2012/07/17 12:05), Steven Rostedt wrote: > On Tue, 2012-07-17 at 11:08 +0900, Masami Hiramatsu wrote: > >>> I found that regs_get_register() doesn't honor this either. Thus, >>> kprobes in tracing gets this: >>> >>> # echo 'p:ftrace sys_read+4 s=%sp' > /debug/tracing/kprobe_events >>> # echo 1 > /debug/tracing/events/kprobes/enable >>> # cat trace >>> sshd-1345 [000] d... 489.117168: ftrace: (sys_read+0x4/0x70) >>> s=b7e96768 >>> sshd-1345 [000] d... 489.117191: ftrace: (sys_read+0x4/0x70) >>> s=b7e96768 >>> cat-1447 [000] d... 489.117392: ftrace: (sys_read+0x4/0x70) >>> s=5a7 >>> cat-1447 [001] d... 489.118023: ftrace: (sys_read+0x4/0x70) >>> s=b77ad05f >>> less-1448 [000] d... 489.118079: ftrace: (sys_read+0x4/0x70) >>> s=b7762e06 >>> less-1448 [000] d... 489.118117: ftrace: (sys_read+0x4/0x70) >>> s=b7764970 >>> >> >> Yes, that is by design, since I made it so. :) >> Instead of %sp, kprobe tracer provides $stack special argument >> for stack address, because "sp" is not always means the stack >> address on every arch. > > But is that useful? Wouldn't the actual stack pointer be more > informative?
It is just FYI :). I rather like your "%sp" enhancement than current meaningless "%sp" on i386... However, I think "$stack" is more general and informative for users, thus, at least perf probe uses it for getting variables from stack. Thank you, -- Masami HIRAMATSU Software Platform Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu...@hitachi.com -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
