1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2013 Linaro Ltd;  <roy.franz@linaro.org>
4 */
5#include <linux/efi.h>
6#include <asm/efi.h>
7
8#include "efistub.h"
9
10static efi_guid_t cpu_state_guid = LINUX_EFI_ARM_CPU_STATE_TABLE_GUID;
11
12struct efi_arm_entry_state *efi_entry_state;
13
14static void get_cpu_state(u32 *cpsr, u32 *sctlr)
15{
16	asm("mrs %0, cpsr" : "=r"(*cpsr));
17	if ((*cpsr & MODE_MASK) == HYP_MODE)
18		asm("mrc p15, 4, %0, c1, c0, 0" : "=r"(*sctlr));
19	else
20		asm("mrc p15, 0, %0, c1, c0, 0" : "=r"(*sctlr));
21}
22
23efi_status_t check_platform_features(void)
24{
25	efi_status_t status;
26	u32 cpsr, sctlr;
27	int block;
28
29	get_cpu_state(&cpsr, &sctlr);
30
31	efi_info("Entering in %s mode with MMU %sabled\n",
32		 ((cpsr & MODE_MASK) == HYP_MODE) ? "HYP" : "SVC",
33		 (sctlr & 1) ? "en" : "dis");
34
35	status = efi_bs_call(allocate_pool, EFI_LOADER_DATA,
36			     sizeof(*efi_entry_state),
37			     (void **)&efi_entry_state);
38	if (status != EFI_SUCCESS) {
39		efi_err("allocate_pool() failed\n");
40		return status;
41	}
42
43	efi_entry_state->cpsr_before_ebs = cpsr;
44	efi_entry_state->sctlr_before_ebs = sctlr;
45
46	status = efi_bs_call(install_configuration_table, &cpu_state_guid,
47			     efi_entry_state);
48	if (status != EFI_SUCCESS) {
49		efi_err("install_configuration_table() failed\n");
50		goto free_state;
51	}
52
53	/* non-LPAE kernels can run anywhere */
54	if (!IS_ENABLED(CONFIG_ARM_LPAE))
55		return EFI_SUCCESS;
56
57	/* LPAE kernels need compatible hardware */
58	block = cpuid_feature_extract(CPUID_EXT_MMFR0, 0);
59	if (block < 5) {
60		efi_err("This LPAE kernel is not supported by your CPU\n");
61		status = EFI_UNSUPPORTED;
62		goto drop_table;
63	}
64	return EFI_SUCCESS;
65
66drop_table:
67	efi_bs_call(install_configuration_table, &cpu_state_guid, NULL);
68free_state:
69	efi_bs_call(free_pool, efi_entry_state);
70	return status;
71}
72
73void efi_handle_post_ebs_state(void)
74{
75	get_cpu_state(&efi_entry_state->cpsr_after_ebs,
76		      &efi_entry_state->sctlr_after_ebs);
77}
78
79efi_status_t handle_kernel_image(unsigned long *image_addr,
80				 unsigned long *image_size,
81				 unsigned long *reserve_addr,
82				 unsigned long *reserve_size,
83				 efi_loaded_image_t *image,
84				 efi_handle_t image_handle)
85{
86	const int slack = TEXT_OFFSET - 5 * PAGE_SIZE;
87	int alloc_size = MAX_UNCOMP_KERNEL_SIZE + EFI_PHYS_ALIGN;
88	unsigned long alloc_base, kernel_base;
89	efi_status_t status;
90
91	/*
92	 * Allocate space for the decompressed kernel as low as possible.
93	 * The region should be 16 MiB aligned, but the first 'slack' bytes
94	 * are not used by Linux, so we allow those to be occupied by the
95	 * firmware.
96	 */
97	status = efi_low_alloc_above(alloc_size, EFI_PAGE_SIZE, &alloc_base, 0x0);
98	if (status != EFI_SUCCESS) {
99		efi_err("Unable to allocate memory for uncompressed kernel.\n");
100		return status;
101	}
102
103	if ((alloc_base % EFI_PHYS_ALIGN) > slack) {
104		/*
105		 * More than 'slack' bytes are already occupied at the base of
106		 * the allocation, so we need to advance to the next 16 MiB block.
107		 */
108		kernel_base = round_up(alloc_base, EFI_PHYS_ALIGN);
109		efi_info("Free memory starts at 0x%lx, setting kernel_base to 0x%lx\n",
110			 alloc_base, kernel_base);
111	} else {
112		kernel_base = round_down(alloc_base, EFI_PHYS_ALIGN);
113	}
114
115	*reserve_addr = kernel_base + slack;
116	*reserve_size = MAX_UNCOMP_KERNEL_SIZE;
117
118	/* now free the parts that we will not use */
119	if (*reserve_addr > alloc_base) {
120		efi_bs_call(free_pages, alloc_base,
121			    (*reserve_addr - alloc_base) / EFI_PAGE_SIZE);
122		alloc_size -= *reserve_addr - alloc_base;
123	}
124	efi_bs_call(free_pages, *reserve_addr + MAX_UNCOMP_KERNEL_SIZE,
125		    (alloc_size - MAX_UNCOMP_KERNEL_SIZE) / EFI_PAGE_SIZE);
126
127	*image_addr = kernel_base + TEXT_OFFSET;
128	*image_size = 0;
129
130	efi_debug("image addr == 0x%lx, reserve_addr == 0x%lx\n",
131		  *image_addr, *reserve_addr);
132
133	return EFI_SUCCESS;
134}
135