| From 5eeac049a9b773491c707b38de25b9ab55724ff3 Mon Sep 17 00:00:00 2001 |
| From: Ard Biesheuvel <ard.biesheuvel@linaro.org> |
| Date: Tue, 29 Oct 2019 18:37:53 +0100 |
| Subject: [PATCH] efi: libstub/arm: Account for firmware reserved memory at the |
| base of RAM |
| |
| commit 41cd96fa149b29684ebd38759fefb07f9c7d5276 upstream. |
| |
| The EFI stubloader for ARM starts out by allocating a 32 MB window |
| at the base of RAM, in order to ensure that the decompressor (which |
| blindly copies the uncompressed kernel into that window) does not |
| overwrite other allocations that are made while running in the context |
| of the EFI firmware. |
| |
| In some cases, (e.g., U-Boot running on the Raspberry Pi 2), this is |
| causing boot failures because this initial allocation conflicts with |
| a page of reserved memory at the base of RAM that contains the SMP spin |
| tables and other pieces of firmware data and which was put there by |
| the bootloader under the assumption that the TEXT_OFFSET window right |
| below the kernel is only used partially during early boot, and will be |
| left alone once the memory reservations are processed and taken into |
| account. |
| |
| So let's permit reserved memory regions to exist in the region starting |
| at the base of RAM, and ending at TEXT_OFFSET - 5 * PAGE_SIZE, which is |
| the window below the kernel that is not touched by the early boot code. |
| |
| Tested-by: Guillaume Gardet <Guillaume.Gardet@arm.com> |
| Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> |
| Acked-by: Chester Lin <clin@suse.com> |
| Cc: Linus Torvalds <torvalds@linux-foundation.org> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Thomas Gleixner <tglx@linutronix.de> |
| Cc: linux-efi@vger.kernel.org |
| Link: https://lkml.kernel.org/r/20191029173755.27149-5-ardb@kernel.org |
| Signed-off-by: Ingo Molnar <mingo@kernel.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile |
| index 0460c7581220..ee0661ddb25b 100644 |
| --- a/drivers/firmware/efi/libstub/Makefile |
| +++ b/drivers/firmware/efi/libstub/Makefile |
| @@ -52,6 +52,7 @@ lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o random.o \ |
| |
| lib-$(CONFIG_ARM) += arm32-stub.o |
| lib-$(CONFIG_ARM64) += arm64-stub.o |
| +CFLAGS_arm32-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) |
| CFLAGS_arm64-stub.o := -DTEXT_OFFSET=$(TEXT_OFFSET) |
| |
| # |
| diff --git a/drivers/firmware/efi/libstub/arm32-stub.c b/drivers/firmware/efi/libstub/arm32-stub.c |
| index e8f7aefb6813..ffa242ad0a82 100644 |
| --- a/drivers/firmware/efi/libstub/arm32-stub.c |
| +++ b/drivers/firmware/efi/libstub/arm32-stub.c |
| @@ -195,6 +195,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, |
| unsigned long dram_base, |
| efi_loaded_image_t *image) |
| { |
| + unsigned long kernel_base; |
| efi_status_t status; |
| |
| /* |
| @@ -204,9 +205,18 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, |
| * loaded. These assumptions are made by the decompressor, |
| * before any memory map is available. |
| */ |
| - dram_base = round_up(dram_base, SZ_128M); |
| + kernel_base = round_up(dram_base, SZ_128M); |
| |
| - status = reserve_kernel_base(sys_table, dram_base, reserve_addr, |
| + /* |
| + * Note that some platforms (notably, the Raspberry Pi 2) put |
| + * spin-tables and other pieces of firmware at the base of RAM, |
| + * abusing the fact that the window of TEXT_OFFSET bytes at the |
| + * base of the kernel image is only partially used at the moment. |
| + * (Up to 5 pages are used for the swapper page tables) |
| + */ |
| + kernel_base += TEXT_OFFSET - 5 * PAGE_SIZE; |
| + |
| + status = reserve_kernel_base(sys_table, kernel_base, reserve_addr, |
| reserve_size); |
| if (status != EFI_SUCCESS) { |
| pr_efi_err(sys_table, "Unable to allocate memory for uncompressed kernel.\n"); |
| @@ -220,7 +230,7 @@ efi_status_t handle_kernel_image(efi_system_table_t *sys_table, |
| *image_size = image->image_size; |
| status = efi_relocate_kernel(sys_table, image_addr, *image_size, |
| *image_size, |
| - dram_base + MAX_UNCOMP_KERNEL_SIZE, 0); |
| + kernel_base + MAX_UNCOMP_KERNEL_SIZE, 0); |
| if (status != EFI_SUCCESS) { |
| pr_efi_err(sys_table, "Failed to relocate kernel.\n"); |
| efi_free(sys_table, *reserve_size, *reserve_addr); |
| -- |
| 2.7.4 |
| |
