xref: /openbmc/linux/arch/arm64/include/asm/efi.h (revision 84b102f5)
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  * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
62  * kernel need greater alignment than we require the segments to be padded to.
63  */
64 #define EFI_KIMG_ALIGN	\
65 	(SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
66 
67 /*
68  * On arm64, we have to ensure that the initrd ends up in the linear region,
69  * which is a 1 GB aligned region of size '1UL << (VA_BITS_MIN - 1)' that is
70  * guaranteed to cover the kernel Image.
71  *
72  * Since the EFI stub is part of the kernel Image, we can relax the
73  * usual requirements in Documentation/arm64/booting.rst, which still
74  * apply to other bootloaders, and are required for some kernel
75  * configurations.
76  */
77 static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
78 {
79 	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
80 }
81 
82 #define alloc_screen_info(x...)		&screen_info
83 
84 static inline void free_screen_info(struct screen_info *si)
85 {
86 }
87 
88 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
89 {
90 }
91 
92 #define EFI_ALLOC_ALIGN		SZ_64K
93 
94 /*
95  * On ARM systems, virtually remapped UEFI runtime services are set up in two
96  * distinct stages:
97  * - The stub retrieves the final version of the memory map from UEFI, populates
98  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
99  *   service to communicate the new mapping to the firmware (Note that the new
100  *   mapping is not live at this time)
101  * - During an early initcall(), the EFI system table is permanently remapped
102  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
103  *   into a private set of page tables. If this all succeeds, the Runtime
104  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
105  */
106 
107 static inline void efi_set_pgd(struct mm_struct *mm)
108 {
109 	__switch_mm(mm);
110 
111 	if (system_uses_ttbr0_pan()) {
112 		if (mm != current->active_mm) {
113 			/*
114 			 * Update the current thread's saved ttbr0 since it is
115 			 * restored as part of a return from exception. Enable
116 			 * access to the valid TTBR0_EL1 and invoke the errata
117 			 * workaround directly since there is no return from
118 			 * exception when invoking the EFI run-time services.
119 			 */
120 			update_saved_ttbr0(current, mm);
121 			uaccess_ttbr0_enable();
122 			post_ttbr_update_workaround();
123 		} else {
124 			/*
125 			 * Defer the switch to the current thread's TTBR0_EL1
126 			 * until uaccess_enable(). Restore the current
127 			 * thread's saved ttbr0 corresponding to its active_mm
128 			 */
129 			uaccess_ttbr0_disable();
130 			update_saved_ttbr0(current, current->active_mm);
131 		}
132 	}
133 }
134 
135 void efi_virtmap_load(void);
136 void efi_virtmap_unload(void);
137 
138 static inline void efi_capsule_flush_cache_range(void *addr, int size)
139 {
140 	__flush_dcache_area(addr, size);
141 }
142 
143 #endif /* _ASM_EFI_H */
144