xref: /openbmc/linux/arch/arm64/include/asm/efi.h (revision 711aab1d)
1 #ifndef _ASM_EFI_H
2 #define _ASM_EFI_H
3 
4 #include <asm/boot.h>
5 #include <asm/cpufeature.h>
6 #include <asm/fpsimd.h>
7 #include <asm/io.h>
8 #include <asm/memory.h>
9 #include <asm/mmu_context.h>
10 #include <asm/neon.h>
11 #include <asm/ptrace.h>
12 #include <asm/tlbflush.h>
13 
14 #ifdef CONFIG_EFI
15 extern void efi_init(void);
16 #else
17 #define efi_init()
18 #endif
19 
20 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
21 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
22 
23 #define arch_efi_call_virt_setup()					\
24 ({									\
25 	efi_virtmap_load();						\
26 	__efi_fpsimd_begin();						\
27 })
28 
29 #define arch_efi_call_virt(p, f, args...)				\
30 ({									\
31 	efi_##f##_t *__f;						\
32 	__f = p->f;							\
33 	__f(args);							\
34 })
35 
36 #define arch_efi_call_virt_teardown()					\
37 ({									\
38 	__efi_fpsimd_end();						\
39 	efi_virtmap_unload();						\
40 })
41 
42 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
43 
44 /* arch specific definitions used by the stub code */
45 
46 /*
47  * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
48  * start of kernel and may not cross a 2MiB boundary. We set alignment to
49  * 2MiB so we know it won't cross a 2MiB boundary.
50  */
51 #define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
52 
53 /*
54  * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
55  * kernel need greater alignment than we require the segments to be padded to.
56  */
57 #define EFI_KIMG_ALIGN	\
58 	(SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
59 
60 /* on arm64, the FDT may be located anywhere in system RAM */
61 static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
62 {
63 	return ULONG_MAX;
64 }
65 
66 /*
67  * On arm64, we have to ensure that the initrd ends up in the linear region,
68  * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is
69  * guaranteed to cover the kernel Image.
70  *
71  * Since the EFI stub is part of the kernel Image, we can relax the
72  * usual requirements in Documentation/arm64/booting.txt, which still
73  * apply to other bootloaders, and are required for some kernel
74  * configurations.
75  */
76 static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
77 						    unsigned long image_addr)
78 {
79 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1));
80 }
81 
82 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
83 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
84 #define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
85 #define efi_is_64bit()			(true)
86 
87 #define efi_call_proto(protocol, f, instance, ...)			\
88 	((protocol##_t *)instance)->f(instance, ##__VA_ARGS__)
89 
90 #define alloc_screen_info(x...)		&screen_info
91 #define free_screen_info(x...)
92 
93 /* redeclare as 'hidden' so the compiler will generate relative references */
94 extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
95 
96 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
97 {
98 }
99 
100 #define EFI_ALLOC_ALIGN		SZ_64K
101 
102 /*
103  * On ARM systems, virtually remapped UEFI runtime services are set up in two
104  * distinct stages:
105  * - The stub retrieves the final version of the memory map from UEFI, populates
106  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
107  *   service to communicate the new mapping to the firmware (Note that the new
108  *   mapping is not live at this time)
109  * - During an early initcall(), the EFI system table is permanently remapped
110  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
111  *   into a private set of page tables. If this all succeeds, the Runtime
112  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
113  */
114 
115 static inline void efi_set_pgd(struct mm_struct *mm)
116 {
117 	__switch_mm(mm);
118 
119 	if (system_uses_ttbr0_pan()) {
120 		if (mm != current->active_mm) {
121 			/*
122 			 * Update the current thread's saved ttbr0 since it is
123 			 * restored as part of a return from exception. Set
124 			 * the hardware TTBR0_EL1 using cpu_switch_mm()
125 			 * directly to enable potential errata workarounds.
126 			 */
127 			update_saved_ttbr0(current, mm);
128 			cpu_switch_mm(mm->pgd, mm);
129 		} else {
130 			/*
131 			 * Defer the switch to the current thread's TTBR0_EL1
132 			 * until uaccess_enable(). Restore the current
133 			 * thread's saved ttbr0 corresponding to its active_mm
134 			 * (if different from init_mm).
135 			 */
136 			cpu_set_reserved_ttbr0();
137 			if (current->active_mm != &init_mm)
138 				update_saved_ttbr0(current, current->active_mm);
139 		}
140 	}
141 }
142 
143 void efi_virtmap_load(void);
144 void efi_virtmap_unload(void);
145 
146 #endif /* _ASM_EFI_H */
147