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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2013, 2014 Linaro Ltd; <roy.franz@linaro.org>
*
* This file implements the EFI boot stub for the arm64 kernel.
* Adapted from ARM version by Mark Salter <msalter@redhat.com>
*/
#include <linux/efi.h>
#include <asm/efi.h>
#include <asm/image.h>
#include <asm/memory.h>
#include <asm/sysreg.h>
#include "efistub.h"
static bool system_needs_vamap(void)
{
const struct efi_smbios_type4_record *record;
const u32 __aligned(1) *socid;
const u8 *version;
/*
* Ampere eMAG, Altra, and Altra Max machines crash in SetTime() if
* SetVirtualAddressMap() has not been called prior. Most Altra systems
* can be identified by the SMCCC soc ID, which is conveniently exposed
* via the type 4 SMBIOS records. Otherwise, test the processor version
* field. eMAG systems all appear to have the processor version field
* set to "eMAG".
*/
record = (struct efi_smbios_type4_record *)efi_get_smbios_record(4);
if (!record)
return false;
socid = (u32 *)record->processor_id;
switch (*socid & 0xffff000f) {
static char const altra[] = "Ampere(TM) Altra(TM) Processor";
static char const emag[] = "eMAG";
default:
version = efi_get_smbios_string(record, processor_version);
if (!version || (strncmp(version, altra, sizeof(altra) - 1) &&
strncmp(version, emag, sizeof(emag) - 1)))
break;
fallthrough;
case 0x0a160001: // Altra
case 0x0a160002: // Altra Max
efi_warn("Working around broken SetVirtualAddressMap()\n");
return true;
}
return false;
}
efi_status_t check_platform_features(void)
{
u64 tg;
/*
* If we have 48 bits of VA space for TTBR0 mappings, we can map the
* UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is
* unnecessary.
*/
if (VA_BITS_MIN >= 48 && !system_needs_vamap())
efi_novamap = true;
/* UEFI mandates support for 4 KB granularity, no need to check */
if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
return EFI_SUCCESS;
tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf;
if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {
if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
efi_err("This 64 KB granular kernel is not supported by your CPU\n");
else
efi_err("This 16 KB granular kernel is not supported by your CPU\n");
return EFI_UNSUPPORTED;
}
return EFI_SUCCESS;
}
#ifdef CONFIG_ARM64_WORKAROUND_CLEAN_CACHE
#define DCTYPE "civac"
#else
#define DCTYPE "cvau"
#endif
u32 __weak code_size;
void efi_cache_sync_image(unsigned long image_base,
unsigned long alloc_size)
{
u32 ctr = read_cpuid_effective_cachetype();
u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
CTR_EL0_DminLine_SHIFT);
/* only perform the cache maintenance if needed for I/D coherency */
if (!(ctr & BIT(CTR_EL0_IDC_SHIFT))) {
unsigned long base = image_base;
unsigned long size = code_size;
do {
asm("dc " DCTYPE ", %0" :: "r"(base));
base += lsize;
size -= lsize;
} while (size >= lsize);
}
asm("ic ialluis");
dsb(ish);
isb();
efi_remap_image(image_base, alloc_size, code_size);
}
unsigned long __weak primary_entry_offset(void)
{
/*
* By default, we can invoke the kernel via the branch instruction in
* the image header, so offset #0. This will be overridden by the EFI
* stub build that is linked into the core kernel, as in that case, the
* image header may not have been loaded into memory, or may be mapped
* with non-executable permissions.
*/
return 0;
}
void __noreturn efi_enter_kernel(unsigned long entrypoint,
unsigned long fdt_addr,
unsigned long fdt_size)
{
void (* __noreturn enter_kernel)(u64, u64, u64, u64);
enter_kernel = (void *)entrypoint + primary_entry_offset();
enter_kernel(fdt_addr, 0, 0, 0);
}
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