1 files changed, 140 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/arm64.c b/drivers/firmware/efi/libstub/arm64.c
new file mode 100644
index 0000000000..446e35eaf3
--- /dev/null
+++ b/drivers/firmware/efi/libstub/arm64.c
@@ -0,0 +1,140 @@
+// 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->header, 4,
+						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);
+}