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Date: Mon, 8 Dec 2014 16:04:52 +0000
From: Dave P Martin <Dave.Martin@arm.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Javi Merino <Javi.Merino@arm.com>,
        "linux-pm@vger.kernel.org" <linux-pm@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Punit Agrawal <Punit.Agrawal@arm.com>,
        "broonie@kernel.org" <broonie@kernel.org>,
        Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC PATCH v6 1/9] tracing: Add array printing helpers
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Thread-Topic: [RFC PATCH v6 1/9] tracing: Add array printing helpers
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On Mon, Dec 08, 2014 at 03:42:10PM +0000, Steven Rostedt wrote:
> On Fri,  5 Dec 2014 19:04:12 +0000
> "Javi Merino" <javi.merino@arm.com> wrote:

[...]

> > +
> > +DEFINE_PRINT_ARRAY(u8, unsigned int, "0x%x");
> > +DEFINE_PRINT_ARRAY(u16, unsigned int, "0x%x");
> > +DEFINE_PRINT_ARRAY(u32, unsigned int, "0x%x");
> > +DEFINE_PRINT_ARRAY(u64, unsigned long long, "0x%llx");
> > +
> 
> I would really like to avoid adding a bunch of macros for each type.
> Can't we have something like this:
> ftrace_print_array(struct trace_seq *p, void *buf, int buf_len, 
> 		int size)
> {
> 	char *prefix = "";
> 	void *ptr = buf;
> 
> 	while (ptr < buf + buf_len) {
> 		switch(size) {
> 		case 8:
> 			trace_seq_printf("%s0x%x", prefix,
> 				*(unsigned char *)ptr);

I think this should be *(u8 *) etc.

Otherwise, I don't have a problem with this approach.  It's less
ugly than my original.

> 			break;
> 		case 16:
> 			trace_seq_printf("%s0x%x", prefix,
> 				*(unsigned short *)ptr);
> 			break;
> 		case 32:
> 			trace_seq_printf("%s0x%x", prefix,
> 				*(unsigned int *)ptr);
> 			break;
> 		case 64:
> 			trace_seq_printf("%s0x%llx", prefix,
> 				*(unsigned long long *)ptr);
> 			break;
> 		default:
> 			BUG();
> 		}
> 		prefix = ",";
> 		ptr += size;
> 	}
> 
> }
> 
> We probably could even make the "BUG()" into a build bug, with a little
> work.

That sounds possible.

Javi?

Cheers
---Dave