[U-Boot] [PATCH 3/6] efi_loader: Track size of pool allocations to allow freeing

[Alexander Graf]

On 30.09.16 02:03, Stefan Brüns wrote:
> allocate_pool has to return a buffer which is 8-byte aligned. Shift the
> region returned by allocate_pages by 8 byte and store the size in the
> headroom. The 8 byte overhead is neglegible, but provides the required
> size when freeing the allocation later.
> 
> Signed-off-by: Stefan Brüns <stefan.bruens at rwth-aachen.de>
> ---
>  lib/efi_loader/efi_boottime.c | 21 +++++++++++++++++++--
>  1 file changed, 19 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index be6f5e8..3e526eb 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -134,18 +134,35 @@ static efi_status_t EFIAPI efi_allocate_pool(int pool_type, unsigned long size,
>  					     void **buffer)
>  {
>  	efi_status_t r;
> +	u64 num_pages = (size + 8 + 0xfff) >> 12;
>  
>  	EFI_ENTRY("%d, %ld, %p", pool_type, size, buffer);
> -	r = efi_allocate_pages(0, pool_type, (size + 0xfff) >> 12, (void*)buffer);

Please base on top of this patch to avoid conflicts:

  http://lists.denx.de/pipermail/u-boot/2016-September/266580.html

> +
> +	if (size == 0) {
> +		*buffer = NULL;
> +		return EFI_EXIT(EFI_SUCCESS);
> +	}
> +
> +	r = efi_allocate_pages(0, pool_type, num_pages, (void *)buffer);
> +	if (r == EFI_SUCCESS) {
> +		*(u64 *)(*buffer) = num_pages;
> +		*buffer = (char *)(*buffer) + 8;
> +	}
> +
>  	return EFI_EXIT(r);
>  }
>  
>  static efi_status_t EFIAPI efi_free_pool(void *buffer)
>  {
>  	efi_status_t r;
> +	u64 num_pages;
>  
>  	EFI_ENTRY("%p", buffer);
> -	r = efi_free_pages((ulong)buffer, 0);
> +
> +	buffer = (char *)(buffer) - 8;

Please add a sanity assert here that verifies that (ulong)buffer &
EFI_PAGE_MASK == 8.


Alex

> +	num_pages = *(u64 *)buffer;
> +
> +	r = efi_free_pages((ulong)buffer, num_pages);
>  	return EFI_EXIT(r);
>  }
>  
>