[U-Boot] [PATCH] efi_loader: make pool allocations cacheline aligned

[Brüns, Stefan]

On Mittwoch, 2. August 2017 11:28:37 CEST Rob Clark wrote:
> On Tue, Aug 1, 2017 at 9:10 PM, Heinrich Schuchardt
[...]
> >> 
> >> @@ -356,7 +356,8 @@ efi_status_t efi_allocate_pool(int pool_type,
> >> unsigned long size,>> 
> >>  {
> >>  
> >>       efi_status_t r;
> >>       efi_physical_addr_t t;
> >> 
> >> -     u64 num_pages = (size + sizeof(u64) + EFI_PAGE_MASK) >>
> >> EFI_PAGE_SHIFT; +     u64 num_pages = DIV_ROUND_UP(size + sizeof(struct
> >> efi_pool_allocation), +                                  EFI_PAGE_SIZE);
> >> 
> >>       if (size == 0) {
> >>       
> >>               *buffer = NULL;
> > 
> > NAK
> > 
> > With DIV_ROUND_UP you introduce a 64bit division. Depending on the
> > architecture this is only available via stdlib which is not available in
> > U-Boot.
> 
> The divisor is a constant power of two so compiler should turn this into a
> shift
> > Please, use
> > + EFI_PAGE_MASK) >> EFI_PAGE_SHIFT;
> > as in the original line.
> 
> This was actually incorrect (missing a "- 1"), which is why I decided
> to stop open-coding DIV_ROUND_UP().

EFI_PAGE_MASK == EFI_PAGE_SIZE - 1

Kind regards,

Stefan