On Thu, Jun 23, 2016 at 12:34:50PM +0100, Matt Fleming wrote:
> efi_mem_reserve() allows us to permanently mark EFI boot services
> regions as reserved, which means we no longer need to copy the image
> data out and into a separate buffer.
>
> Leaving the data in the original boot services region has the added
> benefit that BGRT images can now be passed across kexec reboot.
>
> Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
> Cc: Leif Lindholm <leif.lindholm@xxxxxxxxxx>
> Cc: Peter Jones <pjones@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Mark Rutland <mark.rutland@xxxxxxx>
> Cc: Dave Young <dyoung@xxxxxxxxxx>
> Cc: Josh Boyer <jwboyer@xxxxxxxxxxxxxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
> Cc: Môshe van der Sterre <me@xxxxxxxx>
> Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
This definitely seems like an improvement.
> arch/x86/platform/efi/efi-bgrt.c | 13 ++-----------
> 1 file changed, 2 insertions(+), 11 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
> index 6a2f5691b1ab..6aad870e8962 100644
> --- a/arch/x86/platform/efi/efi-bgrt.c
> +++ b/arch/x86/platform/efi/efi-bgrt.c
> @@ -82,21 +82,12 @@ void __init efi_bgrt_init(void)
> }
> bgrt_image_size = bmp_header.size;
>
> - bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
> + bgrt_image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
> if (!bgrt_image) {
> - pr_notice("Ignoring BGRT: failed to allocate memory for image (wanted %zu bytes)\n",
> - bgrt_image_size);
> - return;
> - }
> -
> - image = memremap(bgrt_tab->image_address, bmp_header.size, MEMREMAP_WB);
> - if (!image) {
> pr_notice("Ignoring BGRT: failed to map image memory\n");
> - kfree(bgrt_image);
> bgrt_image = NULL;
> return;
> }
>
> - memcpy(bgrt_image, image, bgrt_image_size);
> - memunmap(image);
> + efi_mem_reserve(bgrt_tab->image_address, bgrt_image_size);
> }
> --
> 2.7.3
>
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