Messages in this thread |  | | Date | Thu, 21 Oct 2021 16:19:50 +0530 | From | Viresh Kumar <> | Subject | Re: [PATCH V6] gpio: virtio: Add IRQ support |
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On 21-10-21, 12:07, Geert Uytterhoeven wrote: > On Thu, Oct 21, 2021 at 11:52 AM Viresh Kumar <viresh.kumar@linaro.org> wrote: > > The structure will get aligned to the size of largest element and each > > element will be aligned to itself. I don't see how this will break > > even in case of 32/64 bit communication. > > Structures are not aligned to the size of the largest element, but > to the largest alignment needed for each member.
Right, I was talking in terms of the structures we have here for GPIO. The biggest member here (for any structure) is 32bits long, and compiler shouldn't add extra padding here.
> This can be smaller than the size of the largest element. > E.g. alignof(long long) might be 4, not 8.
Right.
> And m68k aligns to two bytes at most.
Interesting, I assumed that it will be 4bytes for 32 bit systems. So in case of m68k, we will see something like this ?
struct foo { u8 a; // aligned to 2 bytes
// padding of 1 byte
u32 b; // aligned to 2 bytes }
-- viresh
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