arch/arm64/include/asm/efi.h

   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_MIN - 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_MIN - 1));
  94 }
  95
  96 #define efi_bs_call(func, ...)  efi_system_table()->boottime->func(__VA_ARGS__)
  97 #define efi_rt_call(func, ...)  efi_system_table()->runtime->func(__VA_ARGS__)
  98 #define efi_is_native()         (true)
  99
 100 #define efi_table_attr(inst, attr)      (inst->attr)
 101
 102 #define efi_call_proto(inst, func, ...) inst->func(inst, ##__VA_ARGS__)
 103
 104 #define alloc_screen_info(x...)         &screen_info
 105
 106 static inline void free_screen_info(struct screen_info *si)
 107 {
 108 }
 109
 110 /* redeclare as 'hidden' so the compiler will generate relative references */
 111 extern struct screen_info screen_info __attribute__((__visibility__("hidden")));
 112
 113 static inline void efifb_setup_from_dmi(struct screen_info *si, const char *opt)
 114 {
 115 }
 116
 117 #define EFI_ALLOC_ALIGN         SZ_64K
 118
 119 /*
 120  * On ARM systems, virtually remapped UEFI runtime services are set up in two
 121  * distinct stages:
 122  * - The stub retrieves the final version of the memory map from UEFI, populates
 123  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
 124  *   service to communicate the new mapping to the firmware (Note that the new
 125  *   mapping is not live at this time)
 126  * - During an early initcall(), the EFI system table is permanently remapped
 127  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
 128  *   into a private set of page tables. If this all succeeds, the Runtime
 129  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
 130  */
 131
 132 static inline void efi_set_pgd(struct mm_struct *mm)
 133 {
 134         __switch_mm(mm);
 135
 136         if (system_uses_ttbr0_pan()) {
 137                 if (mm != current->active_mm) {
 138                         /*
 139                          * Update the current thread's saved ttbr0 since it is
 140                          * restored as part of a return from exception. Enable
 141                          * access to the valid TTBR0_EL1 and invoke the errata
 142                          * workaround directly since there is no return from
 143                          * exception when invoking the EFI run-time services.
 144                          */
 145                         update_saved_ttbr0(current, mm);
 146                         uaccess_ttbr0_enable();
 147                         post_ttbr_update_workaround();
 148                 } else {
 149                         /*
 150                          * Defer the switch to the current thread's TTBR0_EL1
 151                          * until uaccess_enable(). Restore the current
 152                          * thread's saved ttbr0 corresponding to its active_mm
 153                          */
 154                         uaccess_ttbr0_disable();
 155                         update_saved_ttbr0(current, current->active_mm);
 156                 }
 157         }
 158 }
 159
 160 void efi_virtmap_load(void);
 161 void efi_virtmap_unload(void);
 162
 163 #endif /* _ASM_EFI_H */