On 03.12.24 13:06, Sughosh Ganu wrote:
On Sun, 1 Dec 2024 at 20:58, Simon Glass sjg@chromium.org wrote:
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.
Why can't we "allocate" sane values for the env variables in question, similar to what is being done for the apple and qcom boards -- you can refer to arch/arm/mach-apple/board.c:board_late_init(). We won't be facing these issues then. Eventually, there can be a common, platform agnostic function to initialise these values. So, just as a PoC, I added this code to the qemu-arm.c, and no longer observe any overlaps.
diff --git a/board/emulation/qemu-arm/qemu-arm.c b/board/emulation/qemu-arm/qemu-arm.c index 6095cb02b23..bad787f7a65 100644 --- a/board/emulation/qemu-arm/qemu-arm.c +++ b/board/emulation/qemu-arm/qemu-arm.c @@ -109,6 +109,9 @@ int board_init(void)
int board_late_init(void) {
u32 status = 0;/* * Make sure virtio bus is enumerated so that peripherals * on the virtio bus can be discovered by their drivers@@ -119,6 +122,14 @@ int board_late_init(void) if (CONFIG_IS_ENABLED(USB_KEYBOARD)) usb_init();
status |= env_set_hex("loadaddr", lmb_alloc(SZ_2M, SZ_2M));status |= env_set_hex("fdt_addr_r", lmb_alloc(SZ_2M, SZ_2M));status |= env_set_hex("kernel_addr_r", lmb_alloc(SZ_2M, SZ_2M));status |= env_set_hex("ramdisk_addr_r", lmb_alloc(SZ_8M, SZ_2M));
Hello Sughosh,
avoiding fixed addresses would make sense for most boards.
Your suggested memory reservations for the kernel and initrd are way too small. On my system I find
decompressed kernel - 67 MiB initrd - 77 MiB
scriptaddr is missing.
ARM have address restrictions (see function efi_get_max_initrd_addr()):
armv7: max_init_rd_addr = round_down(image_addr, SZ_4M) + SZ_512M
armv8: #define VA_BITS_MIN (48) max_init_rd_addr = round_down(image_addr, SZ_1G) + (1UL << (VA_BITS_MIN - 1))
These are not modeled in your suggestion.
I would suggest to make a single <= 512 MiB allocation for both initrd and kernel to keep both together and then assign the addresses in the allocated area, e.g.
kerneladdr = lmb_alloc(SZ_512M, SZ_4M); if (!kerneladdr) goto err; if (env_set_hex("kernel_addr_r", kerneladdr)) goto err; if (env_set_hex("initrd_addr_r", kerneladdr + SZ_256M)) goto err;
Best regards
Heinrich
if (status)log_warning("late_init: Failed to set run time variables\n");return 0;U-Boot 2025.01-rc3-00042-gacab6e78aca7-dirty (Dec 03 2024 - 17:17:42 +0530)
DRAM: 512 MiB EFI bounce buffer 000000005957f000-000000005d57f000 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#31
starting USB... No USB controllers found Hit any key to stop autoboot: 0
=> bdinfo
...
lmb_dump_all: memory.count = 0x1 memory[0] [0x40000000-0x5fffffff], 0x20000000 bytes, flags: none reserved.count = 0x3 reserved[0] [0x58600000-0x593fffff], 0xe00000 bytes, flags: none reserved[1] [0x5957c000-0x5d57efff], 0x4003000 bytes, flags: no-notify, no-overwrite reserved[2] [0x5d57fde0-0x5fffffff], 0x2a80220 bytes, flags: no-overwrite
...
=> printenv kernel_addr_r kernel_addr_r=58e00000 => printenv ramdisk_addr_r ramdisk_addr_r=58600000 => printenv fdt_addr_r fdt_addr_r=59000000 => printenv loadaddr loadaddr=59200000
-sughosh
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 7e7a6bf31aa..9a880251b47 100644 --- a/lib/efi_loader/efi_bootbin.c +++ b/lib/efi_loader/efi_bootbin.c @@ -208,6 +208,15 @@ 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;-- 2.43.0