On Fri, 11 Apr, at 09:20:44AM, Ingo Molnar wrote:
>
> Might be prudent to do the same in __file_size32(), instead of
> truncating silently, especially is that function too has a u64 output
> AFAICS.
This change isn't required for __file_size32() because we only use that
function if the firmware is 32-bit. The signature of
EFI_FILE_PROTOCOL.GetInfo() looks like this,
EFI_STATUS (*EFI_FILE_GET_INFO) (
EFI_FILE_PROTOCOL *This,
EFI_GUID *InformationType,
UINTN *BufferSize,
void *Buffer
);
UINTN translates to unsigned long, so for 32-bit firmware is u32. The
firmware will never write 64-bits to &info_sz in __file_size32().
> Also, while reviewing the file I noticed that there's "u32 fb_base",
> which is recovered like:
>
> status = __gop_query64(gop64, &info, &size, &fb_base);
>
> but ->frame_buffer_base is u64. Is it always guaranteed u32?
Good catch. ->frame_buffer_base isn't always u32, but we only have u32
bits in which to store it (struct screen_info.lfb_base), so we
implicitly truncate it,
static efi_status_t
__gop_query64(struct efi_graphics_output_protocol_64 *gop64,
[...]
*fb_base = mode->frame_buffer_base;
But you raise a good point - it would probably make more sense to
complain loudly if we get an address above 0xffffffff.
--
Matt Fleming, Intel Open Source Technology Center
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