arch/x86/include/asm/efi.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_X86_EFI_H
   3 #define _ASM_X86_EFI_H
   4
   5 #include <asm/fpu/api.h>
   6 #include <asm/pgtable.h>
   7 #include <asm/processor-flags.h>
   8 #include <asm/tlb.h>
   9 #include <asm/nospec-branch.h>
  10 #include <asm/mmu_context.h>
  11 #include <linux/build_bug.h>
  12
  13 /*
  14  * We map the EFI regions needed for runtime services non-contiguously,
  15  * with preserved alignment on virtual addresses starting from -4G down
  16  * for a total max space of 64G. This way, we provide for stable runtime
  17  * services addresses across kernels so that a kexec'd kernel can still
  18  * use them.
  19  *
  20  * This is the main reason why we're doing stable VA mappings for RT
  21  * services.
  22  *
  23  * SGI UV1 machines are known to be incompatible with this scheme, so we
  24  * provide an opt-out for these machines via a DMI quirk that sets the
  25  * attribute below.
  26  */
  27 #define EFI_UV1_MEMMAP         EFI_ARCH_1
  28
  29 static inline bool efi_have_uv1_memmap(void)
  30 {
  31         return IS_ENABLED(CONFIG_X86_UV) && efi_enabled(EFI_UV1_MEMMAP);
  32 }
  33
  34 #define EFI32_LOADER_SIGNATURE  "EL32"
  35 #define EFI64_LOADER_SIGNATURE  "EL64"
  36
  37 #define MAX_CMDLINE_ADDRESS     UINT_MAX
  38
  39 #define ARCH_EFI_IRQ_FLAGS_MASK X86_EFLAGS_IF
  40
  41 /*
  42  * The EFI services are called through variadic functions in many cases. These
  43  * functions are implemented in assembler and support only a fixed number of
  44  * arguments. The macros below allows us to check at build time that we don't
  45  * try to call them with too many arguments.
  46  *
  47  * __efi_nargs() will return the number of arguments if it is 7 or less, and
  48  * cause a BUILD_BUG otherwise. The limitations of the C preprocessor make it
  49  * impossible to calculate the exact number of arguments beyond some
  50  * pre-defined limit. The maximum number of arguments currently supported by
  51  * any of the thunks is 7, so this is good enough for now and can be extended
  52  * in the obvious way if we ever need more.
  53  */
  54
  55 #define __efi_nargs(...) __efi_nargs_(__VA_ARGS__)
  56 #define __efi_nargs_(...) __efi_nargs__(0, ##__VA_ARGS__,       \
  57         __efi_arg_sentinel(7), __efi_arg_sentinel(6),           \
  58         __efi_arg_sentinel(5), __efi_arg_sentinel(4),           \
  59         __efi_arg_sentinel(3), __efi_arg_sentinel(2),           \
  60         __efi_arg_sentinel(1), __efi_arg_sentinel(0))
  61 #define __efi_nargs__(_0, _1, _2, _3, _4, _5, _6, _7, n, ...)   \
  62         __take_second_arg(n,                                    \
  63                 ({ BUILD_BUG_ON_MSG(1, "__efi_nargs limit exceeded"); 8; }))
  64 #define __efi_arg_sentinel(n) , n
  65
  66 /*
  67  * __efi_nargs_check(f, n, ...) will cause a BUILD_BUG if the ellipsis
  68  * represents more than n arguments.
  69  */
  70
  71 #define __efi_nargs_check(f, n, ...)                                    \
  72         __efi_nargs_check_(f, __efi_nargs(__VA_ARGS__), n)
  73 #define __efi_nargs_check_(f, p, n) __efi_nargs_check__(f, p, n)
  74 #define __efi_nargs_check__(f, p, n) ({                                 \
  75         BUILD_BUG_ON_MSG(                                               \
  76                 (p) > (n),                                              \
  77                 #f " called with too many arguments (" #p ">" #n ")");  \
  78 })
  79
  80 #ifdef CONFIG_X86_32
  81 #define arch_efi_call_virt_setup()                                      \
  82 ({                                                                      \
  83         kernel_fpu_begin();                                             \
  84         firmware_restrict_branch_speculation_start();                   \
  85 })
  86
  87 #define arch_efi_call_virt_teardown()                                   \
  88 ({                                                                      \
  89         firmware_restrict_branch_speculation_end();                     \
  90         kernel_fpu_end();                                               \
  91 })
  92
  93
  94 #define arch_efi_call_virt(p, f, args...)       p->f(args)
  95
  96 #define efi_ioremap(addr, size, type, attr)     ioremap_cache(addr, size)
  97
  98 #else /* !CONFIG_X86_32 */
  99
 100 #define EFI_LOADER_SIGNATURE    "EL64"
 101
 102 extern asmlinkage u64 __efi_call(void *fp, ...);
 103
 104 #define efi_call(...) ({                                                \
 105         __efi_nargs_check(efi_call, 7, __VA_ARGS__);                    \
 106         __efi_call(__VA_ARGS__);                                        \
 107 })
 108
 109 /*
 110  * struct efi_scratch - Scratch space used while switching to/from efi_mm
 111  * @phys_stack: stack used during EFI Mixed Mode
 112  * @prev_mm:    store/restore stolen mm_struct while switching to/from efi_mm
 113  */
 114 struct efi_scratch {
 115         u64                     phys_stack;
 116         struct mm_struct        *prev_mm;
 117 } __packed;
 118
 119 #define arch_efi_call_virt_setup()                                      \
 120 ({                                                                      \
 121         efi_sync_low_kernel_mappings();                                 \
 122         kernel_fpu_begin();                                             \
 123         firmware_restrict_branch_speculation_start();                   \
 124                                                                         \
 125         if (!efi_have_uv1_memmap())                                     \
 126                 efi_switch_mm(&efi_mm);                                 \
 127 })
 128
 129 #define arch_efi_call_virt(p, f, args...)                               \
 130         efi_call((void *)p->f, args)                                    \
 131
 132 #define arch_efi_call_virt_teardown()                                   \
 133 ({                                                                      \
 134         if (!efi_have_uv1_memmap())                                     \
 135                 efi_switch_mm(efi_scratch.prev_mm);                     \
 136                                                                         \
 137         firmware_restrict_branch_speculation_end();                     \
 138         kernel_fpu_end();                                               \
 139 })
 140
 141 extern void __iomem *__init efi_ioremap(unsigned long addr, unsigned long size,
 142                                         u32 type, u64 attribute);
 143
 144 #ifdef CONFIG_KASAN
 145 /*
 146  * CONFIG_KASAN may redefine memset to __memset.  __memset function is present
 147  * only in kernel binary.  Since the EFI stub linked into a separate binary it
 148  * doesn't have __memset().  So we should use standard memset from
 149  * arch/x86/boot/compressed/string.c.  The same applies to memcpy and memmove.
 150  */
 151 #undef memcpy
 152 #undef memset
 153 #undef memmove
 154 #endif
 155
 156 #endif /* CONFIG_X86_32 */
 157
 158 extern struct efi_scratch efi_scratch;
 159 extern void __init efi_set_executable(efi_memory_desc_t *md, bool executable);
 160 extern int __init efi_memblock_x86_reserve_range(void);
 161 extern void __init efi_print_memmap(void);
 162 extern void __init efi_memory_uc(u64 addr, unsigned long size);
 163 extern void __init efi_map_region(efi_memory_desc_t *md);
 164 extern void __init efi_map_region_fixed(efi_memory_desc_t *md);
 165 extern void efi_sync_low_kernel_mappings(void);
 166 extern int __init efi_alloc_page_tables(void);
 167 extern int __init efi_setup_page_tables(unsigned long pa_memmap, unsigned num_pages);
 168 extern void __init old_map_region(efi_memory_desc_t *md);
 169 extern void __init runtime_code_page_mkexec(void);
 170 extern void __init efi_runtime_update_mappings(void);
 171 extern void __init efi_dump_pagetable(void);
 172 extern void __init efi_apply_memmap_quirks(void);
 173 extern int __init efi_reuse_config(u64 tables, int nr_tables);
 174 extern void efi_delete_dummy_variable(void);
 175 extern void efi_switch_mm(struct mm_struct *mm);
 176 extern void efi_recover_from_page_fault(unsigned long phys_addr);
 177 extern void efi_free_boot_services(void);
 178 extern pgd_t * __init efi_uv1_memmap_phys_prolog(void);
 179 extern void __init efi_uv1_memmap_phys_epilog(pgd_t *save_pgd);
 180
 181 struct efi_setup_data {
 182         u64 fw_vendor;
 183         u64 runtime;
 184         u64 tables;
 185         u64 smbios;
 186         u64 reserved[8];
 187 };
 188
 189 extern u64 efi_setup;
 190
 191 #ifdef CONFIG_EFI
 192 extern efi_status_t __efi64_thunk(u32, ...);
 193
 194 #define efi64_thunk(...) ({                                             \
 195         __efi_nargs_check(efi64_thunk, 6, __VA_ARGS__);                 \
 196         __efi64_thunk(__VA_ARGS__);                                     \
 197 })
 198
 199 static inline bool efi_is_mixed(void)
 200 {
 201         if (!IS_ENABLED(CONFIG_EFI_MIXED))
 202                 return false;
 203         return IS_ENABLED(CONFIG_X86_64) && !efi_enabled(EFI_64BIT);
 204 }
 205
 206 static inline bool efi_runtime_supported(void)
 207 {
 208         if (IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT))
 209                 return true;
 210
 211         return IS_ENABLED(CONFIG_EFI_MIXED);
 212 }
 213
 214 extern void parse_efi_setup(u64 phys_addr, u32 data_len);
 215
 216 extern void efifb_setup_from_dmi(struct screen_info *si, const char *opt);
 217
 218 extern void efi_thunk_runtime_setup(void);
 219 efi_status_t efi_set_virtual_address_map(unsigned long memory_map_size,
 220                                          unsigned long descriptor_size,
 221                                          u32 descriptor_version,
 222                                          efi_memory_desc_t *virtual_map);
 223
 224 /* arch specific definitions used by the stub code */
 225
 226 __attribute_const__ bool efi_is_64bit(void);
 227
 228 static inline bool efi_is_native(void)
 229 {
 230         if (!IS_ENABLED(CONFIG_X86_64))
 231                 return true;
 232         if (!IS_ENABLED(CONFIG_EFI_MIXED))
 233                 return true;
 234         return efi_is_64bit();
 235 }
 236
 237 #define efi_mixed_mode_cast(attr)                                       \
 238         __builtin_choose_expr(                                          \
 239                 __builtin_types_compatible_p(u32, __typeof__(attr)),    \
 240                         (unsigned long)(attr), (attr))
 241
 242 #define efi_table_attr(inst, attr)                                      \
 243         (efi_is_native()                                                \
 244                 ? inst->attr                                            \
 245                 : (__typeof__(inst->attr))                              \
 246                         efi_mixed_mode_cast(inst->mixed_mode.attr))
 247
 248 /*
 249  * The following macros allow translating arguments if necessary from native to
 250  * mixed mode. The use case for this is to initialize the upper 32 bits of
 251  * output parameters, and where the 32-bit method requires a 64-bit argument,
 252  * which must be split up into two arguments to be thunked properly.
 253  *
 254  * As examples, the AllocatePool boot service returns the address of the
 255  * allocation, but it will not set the high 32 bits of the address. To ensure
 256  * that the full 64-bit address is initialized, we zero-init the address before
 257  * calling the thunk.
 258  *
 259  * The FreePages boot service takes a 64-bit physical address even in 32-bit
 260  * mode. For the thunk to work correctly, a native 64-bit call of
 261  *      free_pages(addr, size)
 262  * must be translated to
 263  *      efi64_thunk(free_pages, addr & U32_MAX, addr >> 32, size)
 264  * so that the two 32-bit halves of addr get pushed onto the stack separately.
 265  */
 266
 267 static inline void *efi64_zero_upper(void *p)
 268 {
 269         ((u32 *)p)[1] = 0;
 270         return p;
 271 }
 272
 273 #define __efi64_argmap_free_pages(addr, size)                           \
 274         ((addr), 0, (size))
 275
 276 #define __efi64_argmap_get_memory_map(mm_size, mm, key, size, ver)      \
 277         ((mm_size), (mm), efi64_zero_upper(key), efi64_zero_upper(size), (ver))
 278
 279 #define __efi64_argmap_allocate_pool(type, size, buffer)                \
 280         ((type), (size), efi64_zero_upper(buffer))
 281
 282 #define __efi64_argmap_handle_protocol(handle, protocol, interface)     \
 283         ((handle), (protocol), efi64_zero_upper(interface))
 284
 285 #define __efi64_argmap_locate_protocol(protocol, reg, interface)        \
 286         ((protocol), (reg), efi64_zero_upper(interface))
 287
 288 /* PCI I/O */
 289 #define __efi64_argmap_get_location(protocol, seg, bus, dev, func)      \
 290         ((protocol), efi64_zero_upper(seg), efi64_zero_upper(bus),      \
 291          efi64_zero_upper(dev), efi64_zero_upper(func))
 292
 293 /*
 294  * The macros below handle the plumbing for the argument mapping. To add a
 295  * mapping for a specific EFI method, simply define a macro
 296  * __efi64_argmap_<method name>, following the examples above.
 297  */
 298
 299 #define __efi64_thunk_map(inst, func, ...)                              \
 300         efi64_thunk(inst->mixed_mode.func,                              \
 301                 __efi64_argmap(__efi64_argmap_ ## func(__VA_ARGS__),    \
 302                                (__VA_ARGS__)))
 303
 304 #define __efi64_argmap(mapped, args)                                    \
 305         __PASTE(__efi64_argmap__, __efi_nargs(__efi_eat mapped))(mapped, args)
 306 #define __efi64_argmap__0(mapped, args) __efi_eval mapped
 307 #define __efi64_argmap__1(mapped, args) __efi_eval args
 308
 309 #define __efi_eat(...)
 310 #define __efi_eval(...) __VA_ARGS__
 311
 312 /* The three macros below handle dispatching via the thunk if needed */
 313
 314 #define efi_call_proto(inst, func, ...)                                 \
 315         (efi_is_native()                                                \
 316                 ? inst->func(inst, ##__VA_ARGS__)                       \
 317                 : __efi64_thunk_map(inst, func, inst, ##__VA_ARGS__))
 318
 319 #define efi_bs_call(func, ...)                                          \
 320         (efi_is_native()                                                \
 321                 ? efi_system_table()->boottime->func(__VA_ARGS__)       \
 322                 : __efi64_thunk_map(efi_table_attr(efi_system_table(),  \
 323                                 boottime), func, __VA_ARGS__))
 324
 325 #define efi_rt_call(func, ...)                                          \
 326         (efi_is_native()                                                \
 327                 ? efi_system_table()->runtime->func(__VA_ARGS__)        \
 328                 : __efi64_thunk_map(efi_table_attr(efi_system_table(),  \
 329                                 runtime), func, __VA_ARGS__))
 330
 331 extern bool efi_reboot_required(void);
 332 extern bool efi_is_table_address(unsigned long phys_addr);
 333
 334 extern void efi_find_mirror(void);
 335 extern void efi_reserve_boot_services(void);
 336 #else
 337 static inline void parse_efi_setup(u64 phys_addr, u32 data_len) {}
 338 static inline bool efi_reboot_required(void)
 339 {
 340         return false;
 341 }
 342 static inline  bool efi_is_table_address(unsigned long phys_addr)
 343 {
 344         return false;
 345 }
 346 static inline void efi_find_mirror(void)
 347 {
 348 }
 349 static inline void efi_reserve_boot_services(void)
 350 {
 351 }
 352 #endif /* CONFIG_EFI */
 353
 354 #ifdef CONFIG_EFI_FAKE_MEMMAP
 355 extern void __init efi_fake_memmap_early(void);
 356 #else
 357 static inline void efi_fake_memmap_early(void)
 358 {
 359 }
 360 #endif
 361
 362 #endif /* _ASM_X86_EFI_H */