xref: /openbmc/linux/arch/arm64/include/asm/efi.h (revision 174cd4b1)
1 #ifndef _ASM_EFI_H
2 #define _ASM_EFI_H
3 
4 #include <asm/cpufeature.h>
5 #include <asm/io.h>
6 #include <asm/mmu_context.h>
7 #include <asm/neon.h>
8 #include <asm/ptrace.h>
9 #include <asm/tlbflush.h>
10 
11 #ifdef CONFIG_EFI
12 extern void efi_init(void);
13 #else
14 #define efi_init()
15 #endif
16 
17 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
18 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md);
19 
20 #define arch_efi_call_virt_setup()					\
21 ({									\
22 	kernel_neon_begin();						\
23 	efi_virtmap_load();						\
24 })
25 
26 #define arch_efi_call_virt(p, f, args...)				\
27 ({									\
28 	efi_##f##_t *__f;						\
29 	__f = p->f;							\
30 	__f(args);							\
31 })
32 
33 #define arch_efi_call_virt_teardown()					\
34 ({									\
35 	efi_virtmap_unload();						\
36 	kernel_neon_end();						\
37 })
38 
39 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
40 
41 /* arch specific definitions used by the stub code */
42 
43 /*
44  * AArch64 requires the DTB to be 8-byte aligned in the first 512MiB from
45  * start of kernel and may not cross a 2MiB boundary. We set alignment to
46  * 2MiB so we know it won't cross a 2MiB boundary.
47  */
48 #define EFI_FDT_ALIGN	SZ_2M   /* used by allocate_new_fdt_and_exit_boot() */
49 #define MAX_FDT_OFFSET	SZ_512M
50 
51 #define efi_call_early(f, ...)		sys_table_arg->boottime->f(__VA_ARGS__)
52 #define __efi_call_early(f, ...)	f(__VA_ARGS__)
53 #define efi_call_runtime(f, ...)	sys_table_arg->runtime->f(__VA_ARGS__)
54 #define efi_is_64bit()			(true)
55 
56 #define efi_call_proto(protocol, f, instance, ...)			\
57 	((protocol##_t *)instance)->f(instance, ##__VA_ARGS__)
58 
59 #define alloc_screen_info(x...)		&screen_info
60 #define free_screen_info(x...)
61 
62 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
63 {
64 }
65 
66 #define EFI_ALLOC_ALIGN		SZ_64K
67 
68 /*
69  * On ARM systems, virtually remapped UEFI runtime services are set up in two
70  * distinct stages:
71  * - The stub retrieves the final version of the memory map from UEFI, populates
72  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
73  *   service to communicate the new mapping to the firmware (Note that the new
74  *   mapping is not live at this time)
75  * - During an early initcall(), the EFI system table is permanently remapped
76  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
77  *   into a private set of page tables. If this all succeeds, the Runtime
78  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
79  */
80 
81 static inline void efi_set_pgd(struct mm_struct *mm)
82 {
83 	__switch_mm(mm);
84 
85 	if (system_uses_ttbr0_pan()) {
86 		if (mm != current->active_mm) {
87 			/*
88 			 * Update the current thread's saved ttbr0 since it is
89 			 * restored as part of a return from exception. Set
90 			 * the hardware TTBR0_EL1 using cpu_switch_mm()
91 			 * directly to enable potential errata workarounds.
92 			 */
93 			update_saved_ttbr0(current, mm);
94 			cpu_switch_mm(mm->pgd, mm);
95 		} else {
96 			/*
97 			 * Defer the switch to the current thread's TTBR0_EL1
98 			 * until uaccess_enable(). Restore the current
99 			 * thread's saved ttbr0 corresponding to its active_mm
100 			 * (if different from init_mm).
101 			 */
102 			cpu_set_reserved_ttbr0();
103 			if (current->active_mm != &init_mm)
104 				update_saved_ttbr0(current, current->active_mm);
105 		}
106 	}
107 }
108 
109 void efi_virtmap_load(void);
110 void efi_virtmap_unload(void);
111 
112 #endif /* _ASM_EFI_H */
113