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
  18 bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);
  19 #else
  20 #define efi_init()
  21
  22 static inline
  23 bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
  24 {
  25         return false;
  26 }
  27 #endif
  28
  29 int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
  30 int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md,
  31                                 bool has_bti);
  32
  33 #undef arch_efi_call_virt
  34 #define arch_efi_call_virt(p, f, args...)                               \
  35         __efi_rt_asm_wrapper((p)->f, #f, args)
  36
  37 extern u64 *efi_rt_stack_top;
  38 efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
  39
  40 void arch_efi_call_virt_setup(void);
  41 void arch_efi_call_virt_teardown(void);
  42
  43 /*
  44  * efi_rt_stack_top[-1] contains the value the stack pointer had before
  45  * switching to the EFI runtime stack.
  46  */
  47 #define current_in_efi()                                                \
  48         (!preemptible() && efi_rt_stack_top != NULL &&                  \
  49          on_task_stack(current, READ_ONCE(efi_rt_stack_top[-1]), 1))
  50
  51 #define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
  52
  53 /*
  54  * Even when Linux uses IRQ priorities for IRQ disabling, EFI does not.
  55  * And EFI shouldn't really play around with priority masking as it is not aware
  56  * which priorities the OS has assigned to its interrupts.
  57  */
  58 #define arch_efi_save_flags(state_flags)                \
  59         ((void)((state_flags) = read_sysreg(daif)))
  60
  61 #define arch_efi_restore_flags(state_flags)     write_sysreg(state_flags, daif)
  62
  63
  64 /* arch specific definitions used by the stub code */
  65
  66 /*
  67  * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
  68  * kernel need greater alignment than we require the segments to be padded to.
  69  */
  70 #define EFI_KIMG_ALIGN  \
  71         (SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
  72
  73 /*
  74  * On arm64, we have to ensure that the initrd ends up in the linear region,
  75  * which is a 1 GB aligned region of size '1UL << (VA_BITS_MIN - 1)' that is
  76  * guaranteed to cover the kernel Image.
  77  *
  78  * Since the EFI stub is part of the kernel Image, we can relax the
  79  * usual requirements in Documentation/arch/arm64/booting.rst, which still
  80  * apply to other bootloaders, and are required for some kernel
  81  * configurations.
  82  */
  83 static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
  84 {
  85         return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
  86 }
  87
  88 static inline unsigned long efi_get_kimg_min_align(void)
  89 {
  90         extern bool efi_nokaslr;
  91
  92         /*
  93          * Although relocatable kernels can fix up the misalignment with
  94          * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
  95          * subtly out of sync with those recorded in the vmlinux when kaslr is
  96          * disabled but the image required relocation anyway. Therefore retain
  97          * 2M alignment if KASLR was explicitly disabled, even if it was not
  98          * going to be activated to begin with.
  99          */
 100         return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
 101 }
 102
 103 #define EFI_ALLOC_ALIGN         SZ_64K
 104 #define EFI_ALLOC_LIMIT         ((1UL << 48) - 1)
 105
 106 extern unsigned long primary_entry_offset(void);
 107
 108 /*
 109  * On ARM systems, virtually remapped UEFI runtime services are set up in two
 110  * distinct stages:
 111  * - The stub retrieves the final version of the memory map from UEFI, populates
 112  *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
 113  *   service to communicate the new mapping to the firmware (Note that the new
 114  *   mapping is not live at this time)
 115  * - During an early initcall(), the EFI system table is permanently remapped
 116  *   and the virtual remapping of the UEFI Runtime Services regions is loaded
 117  *   into a private set of page tables. If this all succeeds, the Runtime
 118  *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
 119  */
 120
 121 static inline void efi_set_pgd(struct mm_struct *mm)
 122 {
 123         __switch_mm(mm);
 124
 125         if (system_uses_ttbr0_pan()) {
 126                 if (mm != current->active_mm) {
 127                         /*
 128                          * Update the current thread's saved ttbr0 since it is
 129                          * restored as part of a return from exception. Enable
 130                          * access to the valid TTBR0_EL1 and invoke the errata
 131                          * workaround directly since there is no return from
 132                          * exception when invoking the EFI run-time services.
 133                          */
 134                         update_saved_ttbr0(current, mm);
 135                         uaccess_ttbr0_enable();
 136                         post_ttbr_update_workaround();
 137                 } else {
 138                         /*
 139                          * Defer the switch to the current thread's TTBR0_EL1
 140                          * until uaccess_enable(). Restore the current
 141                          * thread's saved ttbr0 corresponding to its active_mm
 142                          */
 143                         uaccess_ttbr0_disable();
 144                         update_saved_ttbr0(current, current->active_mm);
 145                 }
 146         }
 147 }
 148
 149 void efi_virtmap_load(void);
 150 void efi_virtmap_unload(void);
 151
 152 static inline void efi_capsule_flush_cache_range(void *addr, int size)
 153 {
 154         dcache_clean_inval_poc((unsigned long)addr, (unsigned long)addr + size);
 155 }
 156
 157 efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f);
 158
 159 void efi_icache_sync(unsigned long start, unsigned long end);
 160
 161 #endif /* _ASM_EFI_H */