xref: /openbmc/linux/arch/arm64/include/asm/efi.h (revision b8d312aa)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_EFI_H
3 #define _ASM_EFI_H
4 
5 #include <asm/boot.h>
6 #include <asm/cpufeature.h>
7 #include <asm/fpsimd.h>
8 #include <asm/io.h>
9 #include <asm/memory.h>
10 #include <asm/mmu_context.h>
11 #include <asm/neon.h>
12 #include <asm/ptrace.h>
13 #include <asm/tlbflush.h>
14 
15 #ifdef CONFIG_EFI
16 extern void efi_init(void);
17 #else
18 #define efi_init()
19 #endif
20 
21 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
22 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
23 
24 #define arch_efi_call_virt_setup()					\
25 ({									\
26 	efi_virtmap_load();						\
27 	__efi_fpsimd_begin();						\
28 })
29 
30 #define arch_efi_call_virt(p, f, args...)				\
31 ({									\
32 	efi_##f##_t *__f;						\
33 	__f = p->f;							\
34 	__efi_rt_asm_wrapper(__f, #f, args);				\
35 })
36 
37 #define arch_efi_call_virt_teardown()					\
38 ({									\
39 	__efi_fpsimd_end();						\
40 	efi_virtmap_unload();						\
41 })
42 
43 efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
44 
45 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
46 
47 /*
48  * Even when Linux uses IRQ priorities for IRQ disabling, EFI does not.
49  * And EFI shouldn't really play around with priority masking as it is not aware
50  * which priorities the OS has assigned to its interrupts.
51  */
52 #define arch_efi_save_flags(state_flags)		\
53 	((void)((state_flags) = read_sysreg(daif)))
54 
55 #define arch_efi_restore_flags(state_flags)	write_sysreg(state_flags, daif)
56 
57 
58 /* arch specific definitions used by the stub code */
59 
60 /*
61  * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
62  * start of kernel and may not cross a 2MiB boundary. We set alignment to
63  * 2MiB so we know it won't cross a 2MiB boundary.
64  */
65 #define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
66 
67 /*
68  * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
69  * kernel need greater alignment than we require the segments to be padded to.
70  */
71 #define EFI_KIMG_ALIGN	\
72 	(SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
73 
74 /* on arm64, the FDT may be located anywhere in system RAM */
75 static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
76 {
77 	return ULONG_MAX;
78 }
79 
80 /*
81  * On arm64, we have to ensure that the initrd ends up in the linear region,
82  * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is
83  * guaranteed to cover the kernel Image.
84  *
85  * Since the EFI stub is part of the kernel Image, we can relax the
86  * usual requirements in Documentation/arm64/booting.rst, which still
87  * apply to other bootloaders, and are required for some kernel
88  * configurations.
89  */
90 static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
91 						    unsigned long image_addr)
92 {
93 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1));
94 }
95 
96 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
97 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
98 #define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
99 #define efi_is_64bit()			(true)
100 
101 #define efi_table_attr(table, attr, instance)				\
102 	((table##_t *)instance)->attr
103 
104 #define efi_call_proto(protocol, f, instance, ...)			\
105 	((protocol##_t *)instance)->f(instance, ##__VA_ARGS__)
106 
107 #define alloc_screen_info(x...)		&screen_info
108 
109 static inline void free_screen_info(efi_system_table_t *sys_table_arg,
110 				    struct screen_info *si)
111 {
112 }
113 
114 /* redeclare as 'hidden' so the compiler will generate relative references */
115 extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
116 
117 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
118 {
119 }
120 
121 #define EFI_ALLOC_ALIGN		SZ_64K
122 
123 /*
124  * On ARM systems, virtually remapped UEFI runtime services are set up in two
125  * distinct stages:
126  * - The stub retrieves the final version of the memory map from UEFI, populates
127  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
128  *   service to communicate the new mapping to the firmware (Note that the new
129  *   mapping is not live at this time)
130  * - During an early initcall(), the EFI system table is permanently remapped
131  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
132  *   into a private set of page tables. If this all succeeds, the Runtime
133  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
134  */
135 
136 static inline void efi_set_pgd(struct mm_struct *mm)
137 {
138 	__switch_mm(mm);
139 
140 	if (system_uses_ttbr0_pan()) {
141 		if (mm != current->active_mm) {
142 			/*
143 			 * Update the current thread's saved ttbr0 since it is
144 			 * restored as part of a return from exception. Enable
145 			 * access to the valid TTBR0_EL1 and invoke the errata
146 			 * workaround directly since there is no return from
147 			 * exception when invoking the EFI run-time services.
148 			 */
149 			update_saved_ttbr0(current, mm);
150 			uaccess_ttbr0_enable();
151 			post_ttbr_update_workaround();
152 		} else {
153 			/*
154 			 * Defer the switch to the current thread's TTBR0_EL1
155 			 * until uaccess_enable(). Restore the current
156 			 * thread's saved ttbr0 corresponding to its active_mm
157 			 */
158 			uaccess_ttbr0_disable();
159 			update_saved_ttbr0(current, current->active_mm);
160 		}
161 	}
162 }
163 
164 void efi_virtmap_load(void);
165 void efi_virtmap_unload(void);
166 
167 #endif /* _ASM_EFI_H */
168