arch/arm64/include/asm/efi.h

   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/tlbflush.h>
   9
  10 #ifdef CONFIG_EFI
  11 extern void efi_init(void);
  12 #else
  13 #define efi_init()
  14 #endif
  15
  16 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
  17
  18 #define efi_call_virt(f, ...)                                           \
  19 ({                                                                      \
  20         efi_##f##_t *__f;                                               \
  21         efi_status_t __s;                                               \
  22                                                                         \
  23         kernel_neon_begin();                                            \
  24         efi_virtmap_load();                                             \
  25         __f = efi.systab->runtime->f;                                   \
  26         __s = __f(__VA_ARGS__);                                         \
  27         efi_virtmap_unload();                                           \
  28         kernel_neon_end();                                              \
  29         __s;                                                            \
  30 })
  31
  32 #define __efi_call_virt(f, ...)                                         \
  33 ({                                                                      \
  34         efi_##f##_t *__f;                                               \
  35                                                                         \
  36         kernel_neon_begin();                                            \
  37         efi_virtmap_load();                                             \
  38         __f = efi.systab->runtime->f;                                   \
  39         __f(__VA_ARGS__);                                               \
  40         efi_virtmap_unload();                                           \
  41         kernel_neon_end();                                              \
  42 })
  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 #define MAX_FDT_OFFSET  SZ_512M
  53
  54 #define efi_call_early(f, ...) sys_table_arg->boottime->f(__VA_ARGS__)
  55
  56 #define EFI_ALLOC_ALIGN         SZ_64K
  57
  58 /*
  59  * On ARM systems, virtually remapped UEFI runtime services are set up in two
  60  * distinct stages:
  61  * - The stub retrieves the final version of the memory map from UEFI, populates
  62  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
  63  *   service to communicate the new mapping to the firmware (Note that the new
  64  *   mapping is not live at this time)
  65  * - During an early initcall(), the EFI system table is permanently remapped
  66  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
  67  *   into a private set of page tables. If this all succeeds, the Runtime
  68  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
  69  */
  70
  71 static inline void efi_set_pgd(struct mm_struct *mm)
  72 {
  73         __switch_mm(mm);
  74
  75         if (system_uses_ttbr0_pan()) {
  76                 if (mm != current->active_mm) {
  77                         /*
  78                          * Update the current thread's saved ttbr0 since it is
  79                          * restored as part of a return from exception. Set
  80                          * the hardware TTBR0_EL1 using cpu_switch_mm()
  81                          * directly to enable potential errata workarounds.
  82                          */
  83                         update_saved_ttbr0(current, mm);
  84                         cpu_switch_mm(mm->pgd, mm);
  85                 } else {
  86                         /*
  87                          * Defer the switch to the current thread's TTBR0_EL1
  88                          * until uaccess_enable(). Restore the current
  89                          * thread's saved ttbr0 corresponding to its active_mm
  90                          * (if different from init_mm).
  91                          */
  92                         cpu_set_reserved_ttbr0();
  93                         if (current->active_mm != &init_mm)
  94                                 update_saved_ttbr0(current, current->active_mm);
  95                 }
  96         }
  97 }
  98
  99 void efi_virtmap_load(void);
 100 void efi_virtmap_unload(void);
 101
 102 #endif /* _ASM_EFI_H */