85 lines
2.2 KiB
C
85 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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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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#include <linux/efi.h>
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#include <asm/efi.h>
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#include <asm/memory.h>
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#include <asm/sysreg.h>
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#include "efistub.h"
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efi_status_t check_platform_features(void)
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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_EL1_TGRAN_SHIFT) & 0xf;
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if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {
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if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
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efi_err("This 64 KB granular kernel is not supported by your CPU\n");
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else
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efi_err("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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#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
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#define DCTYPE "civac"
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#else
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#define DCTYPE "cvau"
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#endif
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void efi_cache_sync_image(unsigned long image_base,
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unsigned long alloc_size,
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unsigned long code_size)
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{
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u32 ctr = read_cpuid_effective_cachetype();
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u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
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CTR_EL0_DminLine_SHIFT);
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/* only perform the cache maintenance if needed for I/D coherency */
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if (!(ctr & BIT(CTR_EL0_IDC_SHIFT))) {
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do {
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asm("dc " DCTYPE ", %0" :: "r"(image_base));
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image_base += lsize;
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code_size -= lsize;
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} while (code_size >= lsize);
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}
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asm("ic ialluis");
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dsb(ish);
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isb();
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}
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unsigned long __weak primary_entry_offset(void)
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{
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/*
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* By default, we can invoke the kernel via the branch instruction in
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* the image header, so offset #0. This will be overridden by the EFI
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* stub build that is linked into the core kernel, as in that case, the
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* image header may not have been loaded into memory, or may be mapped
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* with non-executable permissions.
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*/
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return 0;
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}
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void __noreturn efi_enter_kernel(unsigned long entrypoint,
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unsigned long fdt_addr,
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unsigned long fdt_size)
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{
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void (* __noreturn enter_kernel)(u64, u64, u64, u64);
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enter_kernel = (void *)entrypoint + primary_entry_offset();
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enter_kernel(fdt_addr, 0, 0, 0);
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}
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