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42b5573403
A kernel built with support for a page size that is not supported by the hardware it runs on cannot boot to a state where it can inform the user about the failure. If we happen to be booting via UEFI, we can fail gracefully so check if the currently configured page size is supported by the hardware before entering the kernel proper. Note that UEFI mandates support for 4 KB pages, so in that case, no check is needed. Tested-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk> Reviewed-by: Jeremy Linton <jeremy.linton@arm.com> Acked-by: Mark Rutland <mark.rutland@arm.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: http://lkml.kernel.org/r/1455712566-16727-10-git-send-email-matt@codeblueprint.co.uk Signed-off-by: Ingo Molnar <mingo@kernel.org>
99 lines
3.2 KiB
C
99 lines
3.2 KiB
C
/*
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* Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org>
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*
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* This file implements the EFI boot stub for the arm64 kernel.
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* Adapted from ARM version by Mark Salter <msalter@redhat.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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*/
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#include <linux/efi.h>
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#include <asm/efi.h>
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#include <asm/sections.h>
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#include <asm/sysreg.h>
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efi_status_t check_platform_features(efi_system_table_t *sys_table_arg)
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{
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u64 tg;
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/* UEFI mandates support for 4 KB granularity, no need to check */
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if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
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return EFI_SUCCESS;
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tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_TGRAN_SHIFT) & 0xf;
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if (tg != ID_AA64MMFR0_TGRAN_SUPPORTED) {
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if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
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pr_efi_err(sys_table_arg, "This 64 KB granular kernel is not supported by your CPU\n");
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else
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pr_efi_err(sys_table_arg, "This 16 KB granular kernel is not supported by your CPU\n");
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return EFI_UNSUPPORTED;
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}
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return EFI_SUCCESS;
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}
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efi_status_t handle_kernel_image(efi_system_table_t *sys_table_arg,
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unsigned long *image_addr,
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unsigned long *image_size,
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unsigned long *reserve_addr,
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unsigned long *reserve_size,
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unsigned long dram_base,
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efi_loaded_image_t *image)
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{
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efi_status_t status;
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unsigned long kernel_size, kernel_memsize = 0;
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unsigned long nr_pages;
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void *old_image_addr = (void *)*image_addr;
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unsigned long preferred_offset;
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/*
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* The preferred offset of the kernel Image is TEXT_OFFSET bytes beyond
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* a 2 MB aligned base, which itself may be lower than dram_base, as
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* long as the resulting offset equals or exceeds it.
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*/
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preferred_offset = round_down(dram_base, SZ_2M) + TEXT_OFFSET;
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if (preferred_offset < dram_base)
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preferred_offset += SZ_2M;
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/* Relocate the image, if required. */
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kernel_size = _edata - _text;
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if (*image_addr != preferred_offset) {
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kernel_memsize = kernel_size + (_end - _edata);
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/*
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* First, try a straight allocation at the preferred offset.
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* This will work around the issue where, if dram_base == 0x0,
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* efi_low_alloc() refuses to allocate at 0x0 (to prevent the
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* address of the allocation to be mistaken for a FAIL return
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* value or a NULL pointer). It will also ensure that, on
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* platforms where the [dram_base, dram_base + TEXT_OFFSET)
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* interval is partially occupied by the firmware (like on APM
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* Mustang), we can still place the kernel at the address
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* 'dram_base + TEXT_OFFSET'.
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*/
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*image_addr = *reserve_addr = preferred_offset;
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nr_pages = round_up(kernel_memsize, EFI_ALLOC_ALIGN) /
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EFI_PAGE_SIZE;
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status = efi_call_early(allocate_pages, EFI_ALLOCATE_ADDRESS,
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EFI_LOADER_DATA, nr_pages,
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(efi_physical_addr_t *)reserve_addr);
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if (status != EFI_SUCCESS) {
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kernel_memsize += TEXT_OFFSET;
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status = efi_low_alloc(sys_table_arg, kernel_memsize,
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SZ_2M, reserve_addr);
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if (status != EFI_SUCCESS) {
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pr_efi_err(sys_table_arg, "Failed to relocate kernel\n");
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return status;
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}
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*image_addr = *reserve_addr + TEXT_OFFSET;
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}
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memcpy((void *)*image_addr, old_image_addr, kernel_size);
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*reserve_size = kernel_memsize;
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}
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return EFI_SUCCESS;
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}
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