Re: [Xen-devel] [PATCH v2 4/6] x86/boot: Rename trampoline_{start, end} to boot_trampoline_{start, end}

From: "David Woodhouse" <dwmw2@infradead.org>
To: "Jan Beulich" <jbeulich@suse.com>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"David Woodhouse" <dwmw2@infradead.org>,
	xen-devel <xen-devel@lists.xenproject.org>,
	"Wei Liu" <wl@xen.org>,
	"\"Roger Pau Monné\"" <roger.pau@citrix.com>
Subject: Re: [Xen-devel] [PATCH v2 4/6] x86/boot: Rename trampoline_{start, end} to boot_trampoline_{start, end}
Date: Tue, 27 Aug 2019 09:31:59 -0000	[thread overview]
Message-ID: <4212ff6ae70fb09cd5517ac588317780.squirrel@twosheds.infradead.org> (raw)
In-Reply-To: <69fad9d8-dd8f-0982-3b87-de83be5b2ae2@suse.com>

> On 19.08.2019 17:24, David Woodhouse wrote:
>> On Mon, 2019-08-12 at 11:55 +0200, Jan Beulich wrote:
>>> On 09.08.2019 17:02, David Woodhouse wrote:
>>>> From: David Woodhouse <dwmw@amazon.co.uk>
>>>>
>>>> In preparation for splitting the boot and permanent trampolines from
>>>> each other. Some of these will change back, but most are boot so do
>>>> the
>>>> plain search/replace that way first, then a subsequent patch will
>>>> extract
>>>> the permanent trampoline code.
>>>
>>> To be honest I don't view it as helpful to do things in this order.
>>> If you first re-arranged the ordering of items within the trampoline,
>>> we'd then not end up with an intermediate state where the labels are
>>> misleading. Is there a reason things can't sensibly be done the other
>>> way around?
>>
>> Obviously I did all this in a working tree first, swore at it a lot and
>> finally got it working, then attempted to split it up into separate
>> meaningful commits which individually made sense. There is plenty of
>> room for subjectivity in the choices I made in that last step.
>>
>> I'm not sure I quite see why you say the labels are misleading. My
>> intent was to apply labels based on what each object is *used* for,
>> despite the fact that to start with they're all actually in the same
>> place. And then to actually move each different type of symbol into its
>> separate section/location to clean things up.
>>
>> Is it just the code comments at the start of trampoline.S that you find
>> misleading in the interim stage? Because those *don't* purely talk
>> about what bootsym/bootdatasym/trampsym/tramp32sym are used for; they
>> do say how they are (eventually) relocated. I suppose I could rip that
>> code comment out of patch #3 completely and add it again in a later
>> commit... or just just add it again. I write code comments in an
>> attempt to be helpful to those who come after me (especially when
>> that's actually myself) but if they're going to cause problems, then
>> maybe they're more hassle than they're worth?
>
> No, it's actually the label names: The "boot" that this patch prefixes
> to them isn't correct until all post-boot (i.e. AP bringup) parts
> have been moved out of the framed block of code.

Hm, OK. AFK at this moment but I'll take another look. Basically there
wasn't a perfect way to label and move things; either way there were
glitches during the transition and my recollection was that I preferred
this one because it was purely cosmetic and only lasted for a commit or
two.

Will see if I can come up with something nicer within the amount of time
it is reasonable to spend on such a transitional issue.

-- 
dwmw2

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