* Re: [RFC][PATCH 1/2] ftrace: Add modify_ftrace_direct()
[not found] ` <20191117171835.35af6c0e@gandalf.local.home>
@ 2019-11-19 6:04 ` Alexei Starovoitov
2019-11-19 14:13 ` Steven Rostedt
0 siblings, 1 reply; 3+ messages in thread
From: Alexei Starovoitov @ 2019-11-19 6:04 UTC (permalink / raw)
To: Steven Rostedt, bpf, Network Development; +Cc: LKML, Ingo Molnar
On Sun, Nov 17, 2019 at 2:18 PM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Fri, 15 Nov 2019 13:51:26 -0800
> Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> > Thanks a lot for implementing it.
> > Switching to iterator just to modify the call.. hmm.
> > So "call direct_bpf_A" gets replaced to "call ftrace_stub" to do the iterator
> > only to patch "call direct_bpf_B" later. I'm struggling to see why do that when
> > arch can provide call to call rewrite easily. x86 and others have such ability
> > already. I don't understand why you want to sacrifice simplicity here.
> > Anyway with all 3 apis (register, modify, unreg) it looks complete.
> > I'll start playing with it on Monday.
>
> Now if you take my latest for-next branch, and add the patch below,
I took your for-next without the extra patch and used it from bpf trampoline.
It's looking good so far. Passed basic testing. Will add more stress tests.
Do you mind doing:
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index 73eb2e93593f..6ddb203ca550 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -256,16 +256,16 @@ struct ftrace_direct_func
*ftrace_find_direct_func(unsigned long addr);
# define ftrace_direct_func_count 0
static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
{
- return -ENODEV;
+ return -ENOTSUPP;
}
static inline int unregister_ftrace_direct(unsigned long ip, unsigned
long addr)
{
- return -ENODEV;
+ return -ENOTSUPP;
}
static inline int modify_ftrace_direct(unsigned long ip,
unsigned long old_addr,
unsigned long new_addr)
{
- return -ENODEV;
+ return -ENOTSUPP;
}
otherwise ENODEV is a valid error when ip is incorrect which is
indistinguishable from ftrace not compiled in.
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [RFC][PATCH 1/2] ftrace: Add modify_ftrace_direct()
2019-11-19 6:04 ` [RFC][PATCH 1/2] ftrace: Add modify_ftrace_direct() Alexei Starovoitov
@ 2019-11-19 14:13 ` Steven Rostedt
2019-11-19 15:37 ` Alexei Starovoitov
0 siblings, 1 reply; 3+ messages in thread
From: Steven Rostedt @ 2019-11-19 14:13 UTC (permalink / raw)
To: Alexei Starovoitov; +Cc: bpf, Network Development, LKML, Ingo Molnar
On Mon, 18 Nov 2019 22:04:28 -0800
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
> I took your for-next without the extra patch and used it from bpf trampoline.
> It's looking good so far. Passed basic testing. Will add more stress tests.
>
> Do you mind doing:
> diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> index 73eb2e93593f..6ddb203ca550 100644
> --- a/include/linux/ftrace.h
> +++ b/include/linux/ftrace.h
> @@ -256,16 +256,16 @@ struct ftrace_direct_func
> *ftrace_find_direct_func(unsigned long addr);
> # define ftrace_direct_func_count 0
> static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
> {
> - return -ENODEV;
> + return -ENOTSUPP;
> }
> static inline int unregister_ftrace_direct(unsigned long ip, unsigned
> long addr)
> {
> - return -ENODEV;
> + return -ENOTSUPP;
> }
> static inline int modify_ftrace_direct(unsigned long ip,
> unsigned long old_addr,
> unsigned long new_addr)
> {
> - return -ENODEV;
> + return -ENOTSUPP;
> }
>
> otherwise ENODEV is a valid error when ip is incorrect which is
> indistinguishable from ftrace not compiled in.
Sure I can add this. Want to add a Signed-off-by to it, and I'll just
pull it in directly? I can write up the change log.
-- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [RFC][PATCH 1/2] ftrace: Add modify_ftrace_direct()
2019-11-19 14:13 ` Steven Rostedt
@ 2019-11-19 15:37 ` Alexei Starovoitov
0 siblings, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2019-11-19 15:37 UTC (permalink / raw)
To: Steven Rostedt; +Cc: bpf, Network Development, LKML, Ingo Molnar
On Tue, Nov 19, 2019 at 6:13 AM Steven Rostedt <rostedt@goodmis.org> wrote:
>
> On Mon, 18 Nov 2019 22:04:28 -0800
> Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:
>
> > I took your for-next without the extra patch and used it from bpf trampoline.
> > It's looking good so far. Passed basic testing. Will add more stress tests.
> >
> > Do you mind doing:
> > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
> > index 73eb2e93593f..6ddb203ca550 100644
> > --- a/include/linux/ftrace.h
> > +++ b/include/linux/ftrace.h
> > @@ -256,16 +256,16 @@ struct ftrace_direct_func
> > *ftrace_find_direct_func(unsigned long addr);
> > # define ftrace_direct_func_count 0
> > static inline int register_ftrace_direct(unsigned long ip, unsigned long addr)
> > {
> > - return -ENODEV;
> > + return -ENOTSUPP;
> > }
> > static inline int unregister_ftrace_direct(unsigned long ip, unsigned
> > long addr)
> > {
> > - return -ENODEV;
> > + return -ENOTSUPP;
> > }
> > static inline int modify_ftrace_direct(unsigned long ip,
> > unsigned long old_addr,
> > unsigned long new_addr)
> > {
> > - return -ENODEV;
> > + return -ENOTSUPP;
> > }
> >
> > otherwise ENODEV is a valid error when ip is incorrect which is
> > indistinguishable from ftrace not compiled in.
>
> Sure I can add this. Want to add a Signed-off-by to it, and I'll just
> pull it in directly? I can write up the change log.
Whichever way is easier for you.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Thanks!
> -- Steve
^ permalink raw reply [flat|nested] 3+ messages in thread
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2019-11-19 6:04 ` [RFC][PATCH 1/2] ftrace: Add modify_ftrace_direct() Alexei Starovoitov
2019-11-19 14:13 ` Steven Rostedt
2019-11-19 15:37 ` Alexei Starovoitov
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