Re: [PATCH -next,v2] efi/libstub: arm32: Use "align" for the size alignment

[cuigaosheng]

Hi Ard,

Thanks for your reply.

In my understanding address and size need to meet consistent alignment 
constraints,If I understand wrong, please reject this patch.

Best,

GaoSheng.

在 2021/11/4 17:26, Ard Biesheuvel 写道:
> On Tue, 2 Nov 2021 at 03:04, Gaosheng Cui <cuigaosheng1@xxxxxxxxxx> wrote:
> > We are doing page-based allocations, and both the address
> > and size must meet alignment constraints, so using "align"
> > for the size alignment is a better choice.
> Why is it a better choice? If I allocate a 2 MB aligned block of
> memory, why is it better to align the size to a multiple of 2 MB as
> well?
>
>
> > Signed-off-by: Gaosheng Cui <cuigaosheng1@xxxxxxxxxx>
> > ---
> >   drivers/firmware/efi/libstub/randomalloc.c | 2 +-
> >   drivers/firmware/efi/libstub/relocate.c    | 2 +-
> >   2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/firmware/efi/libstub/randomalloc.c b/drivers/firmware/efi/libstub/randomalloc.c
> > index 724155b9e10d..7b7159bb035d 100644
> > --- a/drivers/firmware/efi/libstub/randomalloc.c
> > +++ b/drivers/firmware/efi/libstub/randomalloc.c
> > @@ -76,7 +76,7 @@ efi_status_t efi_random_alloc(unsigned long size,
> >          if (align < EFI_ALLOC_ALIGN)
> >                  align = EFI_ALLOC_ALIGN;
> >
> > -       size = round_up(size, EFI_ALLOC_ALIGN);
> > +       size = round_up(size, align);
> >
> >          /* count the suitable slots in each memory map entry */
> >          for (map_offset = 0; map_offset < map_size; map_offset += desc_size) {
> > diff --git a/drivers/firmware/efi/libstub/relocate.c b/drivers/firmware/efi/libstub/relocate.c
> > index 8ee9eb2b9039..d6d27e8c23f8 100644
> > --- a/drivers/firmware/efi/libstub/relocate.c
> > +++ b/drivers/firmware/efi/libstub/relocate.c
> > @@ -50,7 +50,7 @@ efi_status_t efi_low_alloc_above(unsigned long size, unsigned long align,
> >          if (align < EFI_ALLOC_ALIGN)
> >                  align = EFI_ALLOC_ALIGN;
> >
> > -       size = round_up(size, EFI_ALLOC_ALIGN);
> > +       size = round_up(size, align);
> >          nr_pages = size / EFI_PAGE_SIZE;
> >          for (i = 0; i < map_size / desc_size; i++) {
> >                  efi_memory_desc_t *desc;
> > --
> > 2.30.0
> .