xref: /openbmc/linux/arch/arm64/include/asm/efi.h (revision 1c2dd16a)
1 #ifndef _ASM_EFI_H
2 #define _ASM_EFI_H
3 
4 #include <asm/boot.h>
5 #include <asm/cpufeature.h>
6 #include <asm/io.h>
7 #include <asm/mmu_context.h>
8 #include <asm/neon.h>
9 #include <asm/ptrace.h>
10 #include <asm/tlbflush.h>
11 
12 #ifdef CONFIG_EFI
13 extern void efi_init(void);
14 #else
15 #define efi_init()
16 #endif
17 
18 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
19 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
20 
21 #define arch_efi_call_virt_setup()					\
22 ({									\
23 	kernel_neon_begin();						\
24 	efi_virtmap_load();						\
25 })
26 
27 #define arch_efi_call_virt(p, f, args...)				\
28 ({									\
29 	efi_##f##_t *__f;						\
30 	__f = p->f;							\
31 	__f(args);							\
32 })
33 
34 #define arch_efi_call_virt_teardown()					\
35 ({									\
36 	efi_virtmap_unload();						\
37 	kernel_neon_end();						\
38 })
39 
40 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
41 
42 /* arch specific definitions used by the stub code */
43 
44 /*
45  * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
46  * start of kernel and may not cross a 2MiB boundary. We set alignment to
47  * 2MiB so we know it won't cross a 2MiB boundary.
48  */
49 #define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
50 
51 /* on arm64, the FDT may be located anywhere in system RAM */
52 static inline unsigned long efi_get_max_fdt_addr(unsigned long dram_base)
53 {
54 	return ULONG_MAX;
55 }
56 
57 /*
58  * On arm64, we have to ensure that the initrd ends up in the linear region,
59  * which is a 1 GB aligned region of size '1UL << (VA_BITS - 1)' that is
60  * guaranteed to cover the kernel Image.
61  *
62  * Since the EFI stub is part of the kernel Image, we can relax the
63  * usual requirements in Documentation/arm64/booting.txt, which still
64  * apply to other bootloaders, and are required for some kernel
65  * configurations.
66  */
67 static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
68 						    unsigned long image_addr)
69 {
70 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS - 1));
71 }
72 
73 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
74 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
75 #define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
76 #define efi_is_64bit()			(true)
77 
78 #define efi_call_proto(protocol, f, instance, ...)			\
79 	((protocol##_t *)instance)->f(instance, ##__VA_ARGS__)
80 
81 #define alloc_screen_info(x...)		&screen_info
82 #define free_screen_info(x...)
83 
84 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
85 {
86 }
87 
88 #define EFI_ALLOC_ALIGN		SZ_64K
89 
90 /*
91  * On ARM systems, virtually remapped UEFI runtime services are set up in two
92  * distinct stages:
93  * - The stub retrieves the final version of the memory map from UEFI, populates
94  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
95  *   service to communicate the new mapping to the firmware (Note that the new
96  *   mapping is not live at this time)
97  * - During an early initcall(), the EFI system table is permanently remapped
98  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
99  *   into a private set of page tables. If this all succeeds, the Runtime
100  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
101  */
102 
103 static inline void efi_set_pgd(struct mm_struct *mm)
104 {
105 	__switch_mm(mm);
106 
107 	if (system_uses_ttbr0_pan()) {
108 		if (mm != current->active_mm) {
109 			/*
110 			 * Update the current thread's saved ttbr0 since it is
111 			 * restored as part of a return from exception. Set
112 			 * the hardware TTBR0_EL1 using cpu_switch_mm()
113 			 * directly to enable potential errata workarounds.
114 			 */
115 			update_saved_ttbr0(current, mm);
116 			cpu_switch_mm(mm->pgd, mm);
117 		} else {
118 			/*
119 			 * Defer the switch to the current thread's TTBR0_EL1
120 			 * until uaccess_enable(). Restore the current
121 			 * thread's saved ttbr0 corresponding to its active_mm
122 			 * (if different from init_mm).
123 			 */
124 			cpu_set_reserved_ttbr0();
125 			if (current->active_mm != &init_mm)
126 				update_saved_ttbr0(current, current->active_mm);
127 		}
128 	}
129 }
130 
131 void efi_virtmap_load(void);
132 void efi_virtmap_unload(void);
133 
134 #endif /* _ASM_EFI_H */
135