The EFI_LOADER_BOUNCE_BUFFER feature was added many years ago. It is still needed and 24 boards (lx2160ardb_tfa_stmm, lx2162aqds_tfa_SECURE_BOOT and the like) use it.
This feature uses EFI page allocation to create a 64MB buffer 'in space' without any knowledge of where boards intend to load their images. This may result in image corruption or other problems.
For example, if the feature is enabled on qemu_arm64 it puts the EFI bounce buffer at 1045MB, with the kernel at 1028MB and the ramdisk at 1088MB. The kernel is probably smaller than 27MB but the buffer does overlap the ramdisk.
The solution is probably to use BOUNCE_BUFFER instead, with the EFI version being dropped. For now, show the address of the EFI bounce buffer so people have a better chance to debug any problem.
Signed-off-by: Simon Glass sjg@chromium.org --- In response to questions on how to show this problem:
First, add CONFIG_EFI_LOADER_BOUNCE_BUFFER=y to configs/qemu_arm64_defconfig and build
Then, to run: qemu-system-aarch64 -machine virt -nographic -cpu cortex-a57 \ -bios u-boot.bin
U-Boot 2024.10-00809-gae29e5f76e4a-dirty (Oct 11 2024 - 11:48:46 -0600)
DRAM: 128 MiB Core: 51 devices, 14 uclasses, devicetree: board Flash: 64 MiB Loading Environment from Flash... *** Warning - bad CRC, using default environment
In: serial,usbkbd Out: serial,vidconsole Err: serial,vidconsole No USB controllers found Net: eth0: virtio-net#32
starting USB... No USB controllers found Hit any key to stop autoboot: 0 => bootefi hello Enabling coop memory No EFI system partition No EFI system partition Failed to persist EFI variables Missing TPMv2 device for EFI_TCG_PROTOCOL Missing RNG device for EFI_RNG_PROTOCOL Warning: EFI bounce buffer 000000004157f000-000000004557f000 Not loaded from disk Booting /MemoryMapped(0x0,0x47763730,0x31b0) EFI: Call: efi_load_image(false, efi_root, file_path, source_buffer, source_size, &handle) EFI: 0 returned by efi_load_image(false, efi_root, file_path, source_buffer, source_size, &handle) Hello, world! Running on UEFI 2.10 Firmware vendor: Das U-Boot Firmware revision: 20241000 Have device tree Load options: <none> File path: <none> Boot device: /MemoryMapped(0x0,0x47763730,0x31b0) => print kernel_addr_r kernel_addr_r=0x40400000 => print ramdisk_addr_r ramdisk_addr_r=0x44000000 =>
The EFI bounce buffer overlaps with the ramdisk.
Changes in v5: - Drop the word 'warning'
Changes in v4: - Reword the commit message since this feature is needed
lib/efi_loader/efi_bootbin.c | 9 +++++++++ 1 file changed, 9 insertions(+)
diff --git a/lib/efi_loader/efi_bootbin.c b/lib/efi_loader/efi_bootbin.c index a87006b3c0e..6f02c5ed5dd 100644 --- a/lib/efi_loader/efi_bootbin.c +++ b/lib/efi_loader/efi_bootbin.c @@ -209,6 +209,15 @@ efi_status_t efi_binary_run(void *image, size_t size, void *fdt) return -1; }
+#ifdef CONFIG_EFI_LOADER_BOUNCE_BUFFER + /* + * Add a warning about this buffer, since it may conflict with other + * things + */ + log_debug("EFI bounce buffer %p-%p\n", efi_bounce_buffer, + efi_bounce_buffer + EFI_LOADER_BOUNCE_BUFFER_SIZE); +#endif + ret = efi_install_fdt(fdt); if (ret != EFI_SUCCESS) return ret;