Re: [Xen-devel] [PATCH v5 06/10] arm: smccc: handle SMCs according to SMCCC

[Volodymyr Babchuk <volodymyr_babchuk@xxxxxxxx>]

Hi Julien,

On 13.09.17 14:11, Julien Grall wrote:
> Hi,
>
> On 08/31/2017 09:09 PM, Volodymyr Babchuk wrote:
> > +static void fill_uuid(struct cpu_user_regs *regs, const xen_uuid_t *u)
> Actually why do you pass a pointer for u? This requires every caller to 
> introduce temporary variable because the UUID is usually a define.
Hmm, another way probably is to pass a whole structure as a parameter.
Are you suggesting this approach? Something like
fill_uuid(regs, (xen_uuid_t)MY_UUID)?

> With your current solution each caller as to do:
>
> xen_uuid_t foo = MY_UUID;
>
> fill_uuid(regs, &foo);
>
> return true;
>
> What I suggested in the previous version is to get fill_uuid return 
> true. So you make each caller simpler.
Yes, but it will not be correct semantically. There will arise many 
questions:
1. Why helper function that only writes data returns bool?
2. If it returns true, can it return false?
3. Should we check its return value before passing it further?


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