1 files changed, 161 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/efi.h b/arch/arm64/include/asm/efi.h
new file mode 100644
index 000000000..bcd5622aa
--- /dev/null
+++ b/arch/arm64/include/asm/efi.h
@@ -0,0 +1,161 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_EFI_H
+#define _ASM_EFI_H
+
+#include <asm/boot.h>
+#include <asm/cpufeature.h>
+#include <asm/fpsimd.h>
+#include <asm/io.h>
+#include <asm/memory.h>
+#include <asm/mmu_context.h>
+#include <asm/neon.h>
+#include <asm/ptrace.h>
+#include <asm/tlbflush.h>
+
+#ifdef CONFIG_EFI
+extern void efi_init(void);
+
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg);
+#else
+#define efi_init()
+
+static inline
+bool efi_runtime_fixup_exception(struct pt_regs *regs, const char *msg)
+{
+	return false;
+}
+#endif
+
+int efi_create_mapping(struct mm_struct *mm, efi_memory_desc_t *md);
+int efi_set_mapping_permissions(struct mm_struct *mm, efi_memory_desc_t *md,
+				bool has_bti);
+
+#undef arch_efi_call_virt
+#define arch_efi_call_virt(p, f, args...)				\
+	__efi_rt_asm_wrapper((p)->f, #f, args)
+
+extern u64 *efi_rt_stack_top;
+efi_status_t __efi_rt_asm_wrapper(void *, const char *, ...);
+
+void arch_efi_call_virt_setup(void);
+void arch_efi_call_virt_teardown(void);
+
+/*
+ * efi_rt_stack_top[-1] contains the value the stack pointer had before
+ * switching to the EFI runtime stack.
+ */
+#define current_in_efi()						\
+	(!preemptible() && efi_rt_stack_top != NULL &&			\
+	 on_task_stack(current, READ_ONCE(efi_rt_stack_top[-1]), 1))
+
+#define ARCH_EFI_IRQ_FLAGS_MASK (PSR_D_BIT | PSR_A_BIT | PSR_I_BIT | PSR_F_BIT)
+
+/*
+ * Even when Linux uses IRQ priorities for IRQ disabling, EFI does not.
+ * And EFI shouldn't really play around with priority masking as it is not aware
+ * which priorities the OS has assigned to its interrupts.
+ */
+#define arch_efi_save_flags(state_flags)		\
+	((void)((state_flags) = read_sysreg(daif)))
+
+#define arch_efi_restore_flags(state_flags)	write_sysreg(state_flags, daif)
+
+
+/* arch specific definitions used by the stub code */
+
+/*
+ * In some configurations (e.g. VMAP_STACK && 64K pages), stacks built into the
+ * kernel need greater alignment than we require the segments to be padded to.
+ */
+#define EFI_KIMG_ALIGN	\
+	(SEGMENT_ALIGN > THREAD_ALIGN ? SEGMENT_ALIGN : THREAD_ALIGN)
+
+/*
+ * On arm64, we have to ensure that the initrd ends up in the linear region,
+ * which is a 1 GB aligned region of size '1UL << (VA_BITS_MIN - 1)' that is
+ * guaranteed to cover the kernel Image.
+ *
+ * Since the EFI stub is part of the kernel Image, we can relax the
+ * usual requirements in Documentation/arch/arm64/booting.rst, which still
+ * apply to other bootloaders, and are required for some kernel
+ * configurations.
+ */
+static inline unsigned long efi_get_max_initrd_addr(unsigned long image_addr)
+{
+	return (image_addr & ~(SZ_1G - 1UL)) + (1UL << (VA_BITS_MIN - 1));
+}
+
+static inline unsigned long efi_get_kimg_min_align(void)
+{
+	extern bool efi_nokaslr;
+
+	/*
+	 * Although relocatable kernels can fix up the misalignment with
+	 * respect to MIN_KIMG_ALIGN, the resulting virtual text addresses are
+	 * subtly out of sync with those recorded in the vmlinux when kaslr is
+	 * disabled but the image required relocation anyway. Therefore retain
+	 * 2M alignment if KASLR was explicitly disabled, even if it was not
+	 * going to be activated to begin with.
+	 */
+	return efi_nokaslr ? MIN_KIMG_ALIGN : EFI_KIMG_ALIGN;
+}
+
+#define EFI_ALLOC_ALIGN		SZ_64K
+#define EFI_ALLOC_LIMIT		((1UL << 48) - 1)
+
+extern unsigned long primary_entry_offset(void);
+
+/*
+ * On ARM systems, virtually remapped UEFI runtime services are set up in two
+ * distinct stages:
+ * - The stub retrieves the final version of the memory map from UEFI, populates
+ *   the virt_addr fields and calls the SetVirtualAddressMap() [SVAM] runtime
+ *   service to communicate the new mapping to the firmware (Note that the new
+ *   mapping is not live at this time)
+ * - During an early initcall(), the EFI system table is permanently remapped
+ *   and the virtual remapping of the UEFI Runtime Services regions is loaded
+ *   into a private set of page tables. If this all succeeds, the Runtime
+ *   Services are enabled and the EFI_RUNTIME_SERVICES bit set.
+ */
+
+static inline void efi_set_pgd(struct mm_struct *mm)
+{
+	__switch_mm(mm);
+
+	if (system_uses_ttbr0_pan()) {
+		if (mm != current->active_mm) {
+			/*
+			 * Update the current thread's saved ttbr0 since it is
+			 * restored as part of a return from exception. Enable
+			 * access to the valid TTBR0_EL1 and invoke the errata
+			 * workaround directly since there is no return from
+			 * exception when invoking the EFI run-time services.
+			 */
+			update_saved_ttbr0(current, mm);
+			uaccess_ttbr0_enable();
+			post_ttbr_update_workaround();
+		} else {
+			/*
+			 * Defer the switch to the current thread's TTBR0_EL1
+			 * until uaccess_enable(). Restore the current
+			 * thread's saved ttbr0 corresponding to its active_mm
+			 */
+			uaccess_ttbr0_disable();
+			update_saved_ttbr0(current, current->active_mm);
+		}
+	}
+}
+
+void efi_virtmap_load(void);
+void efi_virtmap_unload(void);
+
+static inline void efi_capsule_flush_cache_range(void *addr, int size)
+{
+	dcache_clean_inval_poc((unsigned long)addr, (unsigned long)addr + size);
+}
+
+efi_status_t efi_handle_corrupted_x18(efi_status_t s, const char *f);
+
+void efi_icache_sync(unsigned long start, unsigned long end);
+
+#endif /* _ASM_EFI_H */