1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2013, 2014 Linaro Ltd;  <roy.franz@linaro.org>
4  *
5  * This file implements the EFI boot stub for the arm64 kernel.
6  * Adapted from ARM version by Mark Salter <msalter@redhat.com>
7  */
8 
9 
10 #include <linux/efi.h>
11 #include <asm/efi.h>
12 #include <asm/memory.h>
13 #include <asm/sysreg.h>
14 
15 #include "efistub.h"
16 
17 static bool system_needs_vamap(void)
18 {
19 	const u8 *type1_family = efi_get_smbios_string(1, family);
20 
21 	/*
22 	 * Ampere Altra machines crash in SetTime() if SetVirtualAddressMap()
23 	 * has not been called prior.
24 	 */
25 	if (!type1_family || strcmp(type1_family, "Altra"))
26 		return false;
27 
28 	efi_warn("Working around broken SetVirtualAddressMap()\n");
29 	return true;
30 }
31 
32 efi_status_t check_platform_features(void)
33 {
34 	u64 tg;
35 
36 	/*
37 	 * If we have 48 bits of VA space for TTBR0 mappings, we can map the
38 	 * UEFI runtime regions 1:1 and so calling SetVirtualAddressMap() is
39 	 * unnecessary.
40 	 */
41 	if (VA_BITS_MIN >= 48 && !system_needs_vamap())
42 		efi_novamap = true;
43 
44 	/* UEFI mandates support for 4 KB granularity, no need to check */
45 	if (IS_ENABLED(CONFIG_ARM64_4K_PAGES))
46 		return EFI_SUCCESS;
47 
48 	tg = (read_cpuid(ID_AA64MMFR0_EL1) >> ID_AA64MMFR0_EL1_TGRAN_SHIFT) & 0xf;
49 	if (tg < ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MIN || tg > ID_AA64MMFR0_EL1_TGRAN_SUPPORTED_MAX) {
50 		if (IS_ENABLED(CONFIG_ARM64_64K_PAGES))
51 			efi_err("This 64 KB granular kernel is not supported by your CPU\n");
52 		else
53 			efi_err("This 16 KB granular kernel is not supported by your CPU\n");
54 		return EFI_UNSUPPORTED;
55 	}
56 	return EFI_SUCCESS;
57 }
58 
59 void efi_cache_sync_image(unsigned long image_base,
60 			  unsigned long alloc_size,
61 			  unsigned long code_size)
62 {
63 	u32 ctr = read_cpuid_effective_cachetype();
64 	u64 lsize = 4 << cpuid_feature_extract_unsigned_field(ctr,
65 						CTR_EL0_DminLine_SHIFT);
66 
67 	do {
68 		asm("dc civac, %0" :: "r"(image_base));
69 		image_base += lsize;
70 		alloc_size -= lsize;
71 	} while (alloc_size >= lsize);
72 
73 	asm("ic ialluis");
74 	dsb(ish);
75 	isb();
76 }
77