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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_X86_EFI_H
#define _ASM_X86_EFI_H
#include <asm/fpu/api.h>
#include <asm/processor-flags.h>
#include <asm/tlb.h>
#include <asm/nospec-branch.h>
#include <asm/mmu_context.h>
#include <linux/build_bug.h>
#include <linux/kernel.h>
#include <linux/pgtable.h>
extern unsigned long efi_fw_vendor, efi_config_table;
extern unsigned long efi_mixed_mode_stack_pa;
* 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.
* The EFI services are called through variadic functions in many cases. These
* functions are implemented in assembler and support only a fixed number of
* arguments. The macros below allows us to check at build time that we don't
* try to call them with too many arguments.
* __efi_nargs() will return the number of arguments if it is 7 or less, and
* cause a BUILD_BUG otherwise. The limitations of the C preprocessor make it
* impossible to calculate the exact number of arguments beyond some
* pre-defined limit. The maximum number of arguments currently supported by
* any of the thunks is 7, so this is good enough for now and can be extended
* in the obvious way if we ever need more.
#define __efi_nargs(...) __efi_nargs_(__VA_ARGS__)
#define __efi_nargs_(...) __efi_nargs__(0, ##__VA_ARGS__, \
__efi_arg_sentinel(7), __efi_arg_sentinel(6), \
__efi_arg_sentinel(5), __efi_arg_sentinel(4), \
__efi_arg_sentinel(3), __efi_arg_sentinel(2), \
__efi_arg_sentinel(1), __efi_arg_sentinel(0))
#define __efi_nargs__(_0, _1, _2, _3, _4, _5, _6, _7, n, ...) \
__take_second_arg(n, \
({ BUILD_BUG_ON_MSG(1, "__efi_nargs limit exceeded"); 8; }))
#define __efi_arg_sentinel(n) , n
* __efi_nargs_check(f, n, ...) will cause a BUILD_BUG if the ellipsis
* represents more than n arguments.
#define __efi_nargs_check(f, n, ...) \
__efi_nargs_check_(f, __efi_nargs(__VA_ARGS__), n)
#define __efi_nargs_check_(f, p, n) __efi_nargs_check__(f, p, n)
#define __efi_nargs_check__(f, p, n) ({ \
(p) > (n), \
#f " called with too many arguments (" #p ">" #n ")"); \
static inline void efi_fpu_begin(void)
* The UEFI calling convention (UEFI spec 2.3.2 and 2.3.4) requires
* that FCW and MXCSR (64-bit) must be initialized prior to calling
* UEFI code. (Oddly the spec does not require that the FPU stack
* be empty.)
kernel_fpu_begin_mask(KFPU_387 | KFPU_MXCSR);
static inline void efi_fpu_end(void)
#ifdef CONFIG_X86_32
#define arch_efi_call_virt_setup() \
({ \
efi_fpu_begin(); \
firmware_restrict_branch_speculation_start(); \
#define arch_efi_call_virt_teardown() \
({ \
firmware_restrict_branch_speculation_end(); \
efi_fpu_end(); \
#define arch_efi_call_virt(p, f, args...) p->f(args)
#else /* !CONFIG_X86_32 */
extern asmlinkage u64 __efi_call(void *fp, ...);
#define efi_call(...) ({ \
__efi_nargs_check(efi_call, 7, __VA_ARGS__); \
__efi_call(__VA_ARGS__); \
#define arch_efi_call_virt_setup() \
({ \
efi_sync_low_kernel_mappings(); \
efi_fpu_begin(); \
firmware_restrict_branch_speculation_start(); \
efi_enter_mm(); \
#define arch_efi_call_virt(p, f, args...) \
efi_call((void *)p->f, args) \
#define arch_efi_call_virt_teardown() \
({ \
efi_leave_mm(); \
firmware_restrict_branch_speculation_end(); \
efi_fpu_end(); \
* 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 /* CONFIG_X86_32 */
extern int __init efi_memblock_x86_reserve_range(void);
extern void __init efi_print_memmap(void);
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 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_crash_gracefully_on_page_fault(unsigned long phys_addr);
extern void efi_free_boot_services(void);
void efi_enter_mm(void);
void efi_leave_mm(void);
/* kexec external ABI */
struct efi_setup_data {
u64 fw_vendor;
u64 __unused;
u64 tables;
u64 smbios;
u64 reserved[8];
extern u64 efi_setup;
extern efi_status_t __efi64_thunk(u32, ...);
#define efi64_thunk(...) ({ \
__efi_nargs_check(efi64_thunk, 6, __VA_ARGS__); \
__efi64_thunk(__VA_ARGS__); \
static inline bool efi_is_mixed(void)
return false;
return IS_ENABLED(CONFIG_X86_64) && !efi_enabled(EFI_64BIT);
static inline bool efi_runtime_supported(void)
if (IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT))
return true;
extern void parse_efi_setup(u64 phys_addr, u32 data_len);
extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
extern void efi_thunk_runtime_setup(void);
efi_status_t efi_set_virtual_address_map(unsigned long memory_map_size,
unsigned long descriptor_size,
u32 descriptor_version,
efi_memory_desc_t *virtual_map,
unsigned long systab_phys);
/* arch specific definitions used by the stub code */
static inline bool efi_is_64bit(void)
extern const bool efi_is64;
return efi_is64;
static inline bool efi_is_native(void)
return efi_is_64bit();
#define efi_mixed_mode_cast(attr) \
__builtin_choose_expr( \
__builtin_types_compatible_p(u32, __typeof__(attr)), \
(unsigned long)(attr), (attr))
#define efi_table_attr(inst, attr) \
(efi_is_native() \
? inst->attr \
: (__typeof__(inst->attr)) \
* The following macros allow translating arguments if necessary from native to
* mixed mode. The use case for this is to initialize the upper 32 bits of
* output parameters, and where the 32-bit method requires a 64-bit argument,
* which must be split up into two arguments to be thunked properly.
* As examples, the AllocatePool boot service returns the address of the
* allocation, but it will not set the high 32 bits of the address. To ensure
* that the full 64-bit address is initialized, we zero-init the address before
* calling the thunk.
* The FreePages boot service takes a 64-bit physical address even in 32-bit
* mode. For the thunk to work correctly, a native 64-bit call of
* free_pages(addr, size)
* must be translated to
* efi64_thunk(free_pages, addr & U32_MAX, addr >> 32, size)
* so that the two 32-bit halves of addr get pushed onto the stack separately.
static inline void *efi64_zero_upper(void *p)
((u32 *)p)[1] = 0;
return p;
static inline u32 efi64_convert_status(efi_status_t status)
return (u32)(status | (u64)status >> 32);
#define __efi64_argmap_free_pages(addr, size) \
((addr), 0, (size))
#define __efi64_argmap_get_memory_map(mm_size, mm, key, size, ver) \
((mm_size), (mm), efi64_zero_upper(key), efi64_zero_upper(size), (ver))
#define __efi64_argmap_allocate_pool(type, size, buffer) \
((type), (size), efi64_zero_upper(buffer))
#define __efi64_argmap_create_event(type, tpl, f, c, event) \
((type), (tpl), (f), (c), efi64_zero_upper(event))
#define __efi64_argmap_set_timer(event, type, time) \
((event), (type), lower_32_bits(time), upper_32_bits(time))
#define __efi64_argmap_wait_for_event(num, event, index) \
((num), (event), efi64_zero_upper(index))
#define __efi64_argmap_handle_protocol(handle, protocol, interface) \
((handle), (protocol), efi64_zero_upper(interface))
#define __efi64_argmap_locate_protocol(protocol, reg, interface) \
((protocol), (reg), efi64_zero_upper(interface))
#define __efi64_argmap_locate_device_path(protocol, path, handle) \
((protocol), (path), efi64_zero_upper(handle))
#define __efi64_argmap_exit(handle, status, size, data) \
((handle), efi64_convert_status(status), (size), (data))
/* PCI I/O */
#define __efi64_argmap_get_location(protocol, seg, bus, dev, func) \
((protocol), efi64_zero_upper(seg), efi64_zero_upper(bus), \
efi64_zero_upper(dev), efi64_zero_upper(func))
/* LoadFile */
#define __efi64_argmap_load_file(protocol, path, policy, bufsize, buf) \
((protocol), (path), (policy), efi64_zero_upper(bufsize), (buf))
/* Graphics Output Protocol */
#define __efi64_argmap_query_mode(gop, mode, size, info) \
((gop), (mode), efi64_zero_upper(size), efi64_zero_upper(info))
* The macros below handle the plumbing for the argument mapping. To add a
* mapping for a specific EFI method, simply define a macro
* __efi64_argmap_<method name>, following the examples above.
#define __efi64_thunk_map(inst, func, ...) \
efi64_thunk(inst->mixed_mode.func, \
__efi64_argmap(__efi64_argmap_ ## func(__VA_ARGS__), \
#define __efi64_argmap(mapped, args) \
__PASTE(__efi64_argmap__, __efi_nargs(__efi_eat mapped))(mapped, args)
#define __efi64_argmap__0(mapped, args) __efi_eval mapped
#define __efi64_argmap__1(mapped, args) __efi_eval args
#define __efi_eat(...)
#define __efi_eval(...) __VA_ARGS__
/* The three macros below handle dispatching via the thunk if needed */
#define efi_call_proto(inst, func, ...) \
(efi_is_native() \
? inst->func(inst, ##__VA_ARGS__) \
: __efi64_thunk_map(inst, func, inst, ##__VA_ARGS__))
#define efi_bs_call(func, ...) \
(efi_is_native() \
? efi_system_table->boottime->func(__VA_ARGS__) \
: __efi64_thunk_map(efi_table_attr(efi_system_table, \
boottime), \
func, __VA_ARGS__))
#define efi_rt_call(func, ...) \
(efi_is_native() \
? efi_system_table->runtime->func(__VA_ARGS__) \
: __efi64_thunk_map(efi_table_attr(efi_system_table, \
runtime), \
func, __VA_ARGS__))
#else /* CONFIG_EFI_MIXED */
static inline bool efi_is_64bit(void)
return IS_ENABLED(CONFIG_X86_64);
#endif /* CONFIG_EFI_MIXED */
extern bool efi_reboot_required(void);
extern bool efi_is_table_address(unsigned long phys_addr);
extern void efi_find_mirror(void);
extern void efi_reserve_boot_services(void);
static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {}
static inline bool efi_reboot_required(void)
return false;
static inline bool efi_is_table_address(unsigned long phys_addr)
return false;
static inline void efi_find_mirror(void)
static inline void efi_reserve_boot_services(void)
#endif /* CONFIG_EFI */
extern void __init efi_fake_memmap_early(void);
static inline void efi_fake_memmap_early(void)
#define arch_ima_efi_boot_mode \
({ extern struct boot_params boot_params; boot_params.secure_boot; })
#endif /* _ASM_X86_EFI_H */