[PATCH 11/11] x86/efi-bgrt: Use efi_mem_reserve() to avoid copying image data

From: Matt Fleming
Date: Thu Jun 23 2016 - 07:36:00 EST


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: MÃshe van der Sterre <me@xxxxxxxx>
Signed-off-by: Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
---
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