efi/libstub: Distinguish between native/mixed not 32/64 bit
authorArd Biesheuvel <ardb@kernel.org>
Tue, 24 Dec 2019 15:10:09 +0000 (16:10 +0100)
committerIngo Molnar <mingo@kernel.org>
Wed, 25 Dec 2019 09:49:17 +0000 (10:49 +0100)
Currently, we support mixed mode by casting all boot time firmware
calls to 64-bit explicitly on native 64-bit systems, and to 32-bit
on 32-bit systems or 64-bit systems running with 32-bit firmware.

Due to this explicit awareness of the bitness in the code, we do a
lot of casting even on generic code that is shared with other
architectures, where mixed mode does not even exist. This casting
leads to loss of coverage of type checking by the compiler, which
we should try to avoid.

So instead of distinguishing between 32-bit vs 64-bit, distinguish
between native vs mixed, and limit all the nasty casting and
pointer mangling to the code that actually deals with mixed mode.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Arvind Sankar <nivedita@alum.mit.edu>
Cc: Borislav Petkov <bp@alien8.de>
Cc: James Morse <james.morse@arm.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: https://lkml.kernel.org/r/20191224151025.32482-10-ardb@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
arch/arm/include/asm/efi.h
arch/arm64/include/asm/efi.h
arch/x86/boot/compressed/eboot.c
arch/x86/include/asm/efi.h
drivers/firmware/efi/libstub/efi-stub-helper.c
include/linux/efi.h

index 2306ed783ceb204eabf377a7dde5715822d24bd1..9b0c64c28bffff9c62c0c435d0f560aef717732a 100644 (file)
@@ -52,7 +52,7 @@ void efi_virtmap_unload(void);
 
 #define efi_call_early(f, ...)         sys_table_arg->boottime->f(__VA_ARGS__)
 #define efi_call_runtime(f, ...)       sys_table_arg->runtime->f(__VA_ARGS__)
-#define efi_is_64bit()                 (false)
+#define efi_is_native()                        (true)
 
 #define efi_table_attr(table, attr, instance)                          \
        ((table##_t *)instance)->attr
index 7cfac5e0e310b10a6356082ac27969f1568c4452..189082c44c28cd7a1b9e727849c55c2826bf8ed1 100644 (file)
@@ -95,7 +95,7 @@ static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
 
 #define efi_call_early(f, ...)         sys_table_arg->boottime->f(__VA_ARGS__)
 #define efi_call_runtime(f, ...)       sys_table_arg->runtime->f(__VA_ARGS__)
-#define efi_is_64bit()                 (true)
+#define efi_is_native()                        (true)
 
 #define efi_table_attr(table, attr, instance)                          \
        ((table##_t *)instance)->attr
index 959bcdd8c1fe6c58e06a414812b9824f09185823..990b9337996526973f58d14421d96eeb99d7c33a 100644 (file)
@@ -63,8 +63,7 @@ preserve_pci_rom_image(efi_pci_io_protocol_t *pci, struct pci_setup_rom **__rom)
         * large romsize. The UEFI spec limits the size of option ROMs to 16
         * MiB so we reject any ROMs over 16 MiB in size to catch this.
         */
-       romimage = (void *)(unsigned long)efi_table_attr(efi_pci_io_protocol,
-                                                        romimage, pci);
+       romimage = efi_table_attr(efi_pci_io_protocol, romimage, pci);
        romsize = efi_table_attr(efi_pci_io_protocol, romsize, pci);
        if (!romimage || !romsize || romsize > SZ_16M)
                return EFI_INVALID_PARAMETER;
index 6094e7f49a99f9dfb8e47871aa258bac13617ac6..c27323cb49e578c5bc95c35ff7dcddde8e362be5 100644 (file)
@@ -222,21 +222,42 @@ static inline bool efi_is_64bit(void)
        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)
+static inline bool efi_is_native(void)
+{
+       if (!IS_ENABLED(CONFIG_X86_64))
+               return true;
+       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(table, attr, instance) ({                       \
+       __typeof__(((table##_t *)0)->attr) __ret;                       \
+       if (efi_is_native()) {                                          \
+               __ret = ((table##_t *)(unsigned long)instance)->attr;   \
+       } else {                                                        \
+               __ret = (__typeof__(__ret))efi_mixed_mode_cast(         \
+               ((table##_t *)(unsigned long)instance)->mixed_mode.attr);\
+       }                                                               \
+       __ret;                                                          \
+})
 
 #define efi_call_proto(protocol, f, instance, ...)                     \
-       __efi_early()->call(efi_table_attr(protocol, f, instance),      \
+       __efi_early()->call((unsigned long)                             \
+                               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()->call((unsigned long)                             \
+                               efi_table_attr(efi_boot_services, f,    \
                __efi_early()->boot_services), __VA_ARGS__)
 
 #define efi_call_runtime(f, ...)                                       \
-       __efi_early()->call(efi_table_attr(efi_runtime_services, f,     \
+       __efi_early()->call((unsigned long)                             \
+                               efi_table_attr(efi_runtime_services, f, \
                __efi_early()->runtime_services), __VA_ARGS__)
 
 extern bool efi_reboot_required(void);
index e02579907f2e21abc20511560f1d85feb91527a4..1a814dc235ba669cc82433d4b3e6182ba0b9c676 100644 (file)
@@ -431,9 +431,7 @@ static efi_status_t efi_open_volume(efi_system_table_t *sys_table_arg,
        efi_file_handle_t *fh;
        efi_guid_t fs_proto = EFI_FILE_SYSTEM_GUID;
        efi_status_t status;
-       void *handle = (void *)(unsigned long)efi_table_attr(efi_loaded_image,
-                                                            device_handle,
-                                                            image);
+       void *handle = efi_table_attr(efi_loaded_image, device_handle, image);
 
        status = efi_call_early(handle_protocol, handle,
                                &fs_proto, (void **)&io);
@@ -942,33 +940,20 @@ fail:
        return status;
 }
 
-#define GET_EFI_CONFIG_TABLE(bits)                                     \
-static void *get_efi_config_table##bits(efi_system_table_t *_sys_table,        \
-                                       efi_guid_t guid)                \
-{                                                                      \
-       efi_system_table_##bits##_t *sys_table;                         \
-       efi_config_table_##bits##_t *tables;                            \
-       int i;                                                          \
-                                                                       \
-       sys_table = (typeof(sys_table))_sys_table;                      \
-       tables = (typeof(tables))(unsigned long)sys_table->tables;      \
-                                                                       \
-       for (i = 0; i < sys_table->nr_tables; i++) {                    \
-               if (efi_guidcmp(tables[i].guid, guid) != 0)             \
-                       continue;                                       \
-                                                                       \
-               return (void *)(unsigned long)tables[i].table;          \
-       }                                                               \
-                                                                       \
-       return NULL;                                                    \
-}
-GET_EFI_CONFIG_TABLE(32)
-GET_EFI_CONFIG_TABLE(64)
-
 void *get_efi_config_table(efi_system_table_t *sys_table, efi_guid_t guid)
 {
-       if (efi_is_64bit())
-               return get_efi_config_table64(sys_table, guid);
-       else
-               return get_efi_config_table32(sys_table, guid);
+       unsigned long tables = efi_table_attr(efi_system_table, tables, sys_table);
+       int nr_tables = efi_table_attr(efi_system_table, nr_tables, sys_table);
+       int i;
+
+       for (i = 0; i < nr_tables; i++) {
+               efi_config_table_t *t = (void *)tables;
+
+               if (efi_guidcmp(t->guid, guid) == 0)
+                       return efi_table_attr(efi_config_table, table, t);
+
+               tables += efi_is_native() ? sizeof(efi_config_table_t)
+                                         : sizeof(efi_config_table_32_t);
+       }
+       return NULL;
 }
index 5a220af263b194628470f48530ca7e9de3ee7b83..e9d74e9667c07426ac43be38be003b4e294fa71a 100644 (file)
@@ -49,11 +49,11 @@ typedef u64 efi_physical_addr_t;
 typedef void *efi_handle_t;
 
 #define efi_get_handle_at(array, idx)                                  \
-       (efi_is_64bit() ? (efi_handle_t)(unsigned long)((u64 *)(array))[idx] \
+       (efi_is_native() ? (array)[idx]                                 \
                : (efi_handle_t)(unsigned long)((u32 *)(array))[idx])
 
 #define efi_get_handle_num(size)                                       \
-       ((size) / (efi_is_64bit() ? sizeof(u64) : sizeof(u32)))
+       ((size) / (efi_is_native() ? sizeof(efi_handle_t) : sizeof(u32)))
 
 #define for_each_efi_handle(handle, array, size, i)                    \
        for (i = 0;                                                     \
@@ -805,7 +805,7 @@ typedef struct {
 typedef union {
        struct {
                efi_guid_t guid;
-               unsigned long table;
+               void *table;
        };
        efi_config_table_32_t mixed_mode;
 } efi_config_table_t;