1 files changed, 252 insertions, 0 deletions
diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
new file mode 100644
index 000000000..baa549f8e
--- /dev/null
+++ b/arch/x86/include/asm/efi.h
@@ -0,0 +1,252 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_EFI_H
+#define _ASM_X86_EFI_H
+
+#include <asm/fpu/api.h>
+#include <asm/pgtable.h>
+#include <asm/processor-flags.h>
+#include <asm/tlb.h>
+#include <asm/nospec-branch.h>
+#include <asm/mmu_context.h>
+
+/*
+ * We map the EFI regions needed for runtime services non-contiguously,
+ * with preserved alignment on virtual addresses starting from -4G down
+ * for a total max space of 64G. This way, we provide for stable runtime
+ * services addresses across kernels so that a kexec'd kernel can still
+ * use them.
+ *
+ * This is the main reason why we're doing stable VA mappings for RT
+ * services.
+ *
+ * This flag is used in conjuction with a chicken bit called
+ * "efi=old_map" which can be used as a fallback to the old runtime
+ * services mapping method in case there's some b0rkage with a
+ * particular EFI implementation (haha, it is hard to hold up the
+ * sarcasm here...).
+ */
+#define EFI_OLD_MEMMAP		EFI_ARCH_1
+
+#define EFI32_LOADER_SIGNATURE	"EL32"
+#define EFI64_LOADER_SIGNATURE	"EL64"
+
+#define MAX_CMDLINE_ADDRESS	UINT_MAX
+
+#define ARCH_EFI_IRQ_FLAGS_MASK	X86_EFLAGS_IF
+
+#ifdef CONFIG_X86_32
+
+extern asmlinkage unsigned long efi_call_phys(void *, ...);
+
+#define arch_efi_call_virt_setup()					\
+({									\
+	kernel_fpu_begin();						\
+	firmware_restrict_branch_speculation_start();			\
+})
+
+#define arch_efi_call_virt_teardown()					\
+({									\
+	firmware_restrict_branch_speculation_end();			\
+	kernel_fpu_end();						\
+})
+
+
+/*
+ * Wrap all the virtual calls in a way that forces the parameters on the stack.
+ */
+#define arch_efi_call_virt(p, f, args...)				\
+({									\
+	((efi_##f##_t __attribute__((regparm(0)))*) p->f)(args);	\
+})
+
+#define efi_ioremap(addr, size, type, attr)	ioremap_cache(addr, size)
+
+#else /* !CONFIG_X86_32 */
+
+#define EFI_LOADER_SIGNATURE	"EL64"
+
+extern asmlinkage u64 efi_call(void *fp, ...);
+
+#define efi_call_phys(f, args...)		efi_call((f), args)
+
+/*
+ * struct efi_scratch - Scratch space used while switching to/from efi_mm
+ * @phys_stack: stack used during EFI Mixed Mode
+ * @prev_mm:    store/restore stolen mm_struct while switching to/from efi_mm
+ */
+struct efi_scratch {
+	u64			phys_stack;
+	struct mm_struct	*prev_mm;
+} __packed;
+
+#define arch_efi_call_virt_setup()					\
+({									\
+	efi_sync_low_kernel_mappings();					\
+	kernel_fpu_begin();						\
+	firmware_restrict_branch_speculation_start();			\
+									\
+	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+		efi_switch_mm(&efi_mm);					\
+})
+
+#define arch_efi_call_virt(p, f, args...)				\
+	efi_call((void *)p->f, args)					\
+
+#define arch_efi_call_virt_teardown()					\
+({									\
+	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+		efi_switch_mm(efi_scratch.prev_mm);			\
+									\
+	firmware_restrict_branch_speculation_end();			\
+	kernel_fpu_end();						\
+})
+
+extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size,
+					u32 type, u64 attribute);
+
+#ifdef CONFIG_KASAN
+/*
+ * CONFIG_KASAN may redefine memset to __memset.  __memset function is present
+ * only in kernel binary.  Since the EFI stub linked into a separate binary it
+ * doesn't have __memset().  So we should use standard memset from
+ * arch/x86/boot/compressed/string.c.  The same applies to memcpy and memmove.
+ */
+#undef memcpy
+#undef memset
+#undef memmove
+#endif
+
+#endif /* CONFIG_X86_32 */
+
+extern struct efi_scratch efi_scratch;
+extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
+extern int __init efi_memblock_x86_reserve_range(void);
+extern pgd_t * __init efi_call_phys_prolog(void);
+extern void __init efi_call_phys_epilog(pgd_t *save_pgd);
+extern void __init efi_print_memmap(void);
+extern void __init efi_memory_uc(u64 addr, unsigned long size);
+extern void __init efi_map_region(efi_memory_desc_t *md);
+extern void __init efi_map_region_fixed(efi_memory_desc_t *md);
+extern void efi_sync_low_kernel_mappings(void);
+extern int __init efi_alloc_page_tables(void);
+extern int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages);
+extern void __init old_map_region(efi_memory_desc_t *md);
+extern void __init runtime_code_page_mkexec(void);
+extern void __init efi_runtime_update_mappings(void);
+extern void __init efi_dump_pagetable(void);
+extern void __init efi_apply_memmap_quirks(void);
+extern int __init efi_reuse_config(u64 tables, int nr_tables);
+extern void efi_delete_dummy_variable(void);
+extern void efi_switch_mm(struct mm_struct *mm);
+
+struct efi_setup_data {
+	u64 fw_vendor;
+	u64 runtime;
+	u64 tables;
+	u64 smbios;
+	u64 reserved[8];
+};
+
+extern u64 efi_setup;
+
+#ifdef CONFIG_EFI
+
+static inline bool efi_is_native(void)
+{
+	return IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT);
+}
+
+static inline bool efi_runtime_supported(void)
+{
+	if (efi_is_native())
+		return true;
+
+	if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_enabled(EFI_OLD_MEMMAP))
+		return true;
+
+	return false;
+}
+
+extern struct console early_efi_console;
+extern void parse_efi_setup(u64 phys_addr, u32 data_len);
+
+extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
+
+#ifdef CONFIG_EFI_MIXED
+extern void efi_thunk_runtime_setup(void);
+extern efi_status_t efi_thunk_set_virtual_address_map(
+	void *phys_set_virtual_address_map,
+	unsigned long memory_map_size,
+	unsigned long descriptor_size,
+	u32 descriptor_version,
+	efi_memory_desc_t *virtual_map);
+#else
+static inline void efi_thunk_runtime_setup(void) {}
+static inline efi_status_t efi_thunk_set_virtual_address_map(
+	void *phys_set_virtual_address_map,
+	unsigned long memory_map_size,
+	unsigned long descriptor_size,
+	u32 descriptor_version,
+	efi_memory_desc_t *virtual_map)
+{
+	return EFI_SUCCESS;
+}
+#endif /* CONFIG_EFI_MIXED */
+
+
+/* arch specific definitions used by the stub code */
+
+struct efi_config {
+	u64 image_handle;
+	u64 table;
+	u64 runtime_services;
+	u64 boot_services;
+	u64 text_output;
+	efi_status_t (*call)(unsigned long, ...);
+	bool is64;
+} __packed;
+
+__pure const struct efi_config *__efi_early(void);
+
+static inline bool efi_is_64bit(void)
+{
+	if (!IS_ENABLED(CONFIG_X86_64))
+		return false;
+
+	if (!IS_ENABLED(CONFIG_EFI_MIXED))
+		return true;
+
+	return __efi_early()->is64;
+}
+
+#define efi_table_attr(table, attr, instance)				\
+	(efi_is_64bit() ?						\
+		((table##_64_t *)(unsigned long)instance)->attr :	\
+		((table##_32_t *)(unsigned long)instance)->attr)
+
+#define efi_call_proto(protocol, f, instance, ...)			\
+	__efi_early()->call(efi_table_attr(protocol, f, instance),	\
+		instance, ##__VA_ARGS__)
+
+#define efi_call_early(f, ...)						\
+	__efi_early()->call(efi_table_attr(efi_boot_services, f,	\
+		__efi_early()->boot_services), __VA_ARGS__)
+
+#define __efi_call_early(f, ...)					\
+	__efi_early()->call((unsigned long)f, __VA_ARGS__);
+
+#define efi_call_runtime(f, ...)					\
+	__efi_early()->call(efi_table_attr(efi_runtime_services, f,	\
+		__efi_early()->runtime_services), __VA_ARGS__)
+
+extern bool efi_reboot_required(void);
+
+#else
+static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {}
+static inline bool efi_reboot_required(void)
+{
+	return false;
+}
+#endif /* CONFIG_EFI */
+
+#endif /* _ASM_X86_EFI_H */