Messages in this thread | | | Date | Tue, 22 Oct 2019 08:54:28 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/8] ftrace: add ftrace_init_nop() |
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On Tue, 22 Oct 2019 12:28:11 +0100 Mark Rutland <mark.rutland@arm.com> wrote:
> > To make the name even better, let's just rename it to: > > > > ftrace_nop_initialization() > > > > I think that may be the best description for it. > > Perhaps ftrace_nop_initialize(), so that it's not a noun? > > I've made it ftrace_nop_initialization() in my branch for now.
I'm fine with ftrace_nop_initialize().
> > > > diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c > > > index f296d89be757..afd7e210e595 100644 > > > --- a/kernel/trace/ftrace.c > > > +++ b/kernel/trace/ftrace.c > > > @@ -2493,15 +2493,22 @@ struct dyn_ftrace *ftrace_rec_iter_record(struct ftrace_rec_iter *iter) > > > return &iter->pg->records[iter->index]; > > > } > > > > > > +#ifndef ftrace_init_nop > > > +static int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) > > > +{ > > > + return ftrace_make_nop(mod, rec, MCOUNT_ADDR); > > > +} > > > +#endif > > > > Can you place the above in the ftrace.h header. That's where that would > > belong. > > > > #ifndef ftrace_init_nop > > struct module; > > static inline int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) > > { > > return ftrace_make_nop(mod, rec, MCOUNT_ADDR); > > } > > #endif > > True. > > I've put this immediately after ftrace_make_nop() in the header, and > given it a kerneldoc comment. There's a declaration for struct module at > the top of the header, so I've just relied on that > > That looks like: > > | /** > | * ftrace_init_nop - initialize a nop call site > | * @mod: module structure if called by module load initialization > | * @rec: the mcount call site record
Perhaps say "mcount/fentry"
> | * > | * This is a very sensitive operation and great care needs > | * to be taken by the arch. The operation should carefully > | * read the location, check to see if what is read is indeed > | * what we expect it to be, and then on success of the compare, > | * it should write to the location. > | * > | * The code segment at @rec->ip should be as initialized by the
"should be as" is a bit confusing. What about?
"The code segment at @rec->ip should contain the contents created by the compiler".
-- Steve
> | * compiler > | * > | * Return must be: > | * 0 on success > | * -EFAULT on error reading the location > | * -EINVAL on a failed compare of the contents > | * -EPERM on error writing to the location > | * Any other value will be considered a failure. > | */ > | #ifndef ftrace_init_nop > | static int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) > | { > | return ftrace_make_nop(mod, rec, MCOUNT_ADDR); > | } > | #endif > > Thanks, > Mark.
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