efi: Clean up config_parse_tables()

config_parse_tables() is a jumble of pointer arithmetic, due to the
fact that on x86, we may be dealing with firmware whose native word
size differs from the kernel's.

This is not a concern on other architectures, and doesn't quite
justify the state of the code, so let's clean it up by adding a
non-x86 code path, constifying statically allocated tables and
replacing preprocessor conditionals with IS_ENABLED() checks.

Tested-by: Tony Luck <tony.luck@intel.com> # arch/ia64
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/arch/ia64/kernel/efi.c b/arch/ia64/kernel/efi.c
index 3b5cf551489cbec74f2116e0484c88c1fa045140..f69f3fe0532e0ff4ae20e2466d3426961910b057 100644 (file)
--- a/arch/ia64/kernel/efi.c
+++ b/arch/ia64/kernel/efi.c
@@ -56,7 +56,7 @@ unsigned long __initdata esi_phys = EFI_INVALID_TABLE_ADDR;
 unsigned long hcdp_phys = EFI_INVALID_TABLE_ADDR;
 unsigned long sal_systab_phys = EFI_INVALID_TABLE_ADDR;
 
-static __initdata efi_config_table_type_t arch_tables[] = {
+static const efi_config_table_type_t arch_tables[] __initconst = {
        {ESI_TABLE_GUID, "ESI", &esi_phys},
        {HCDP_TABLE_GUID, "HCDP", &hcdp_phys},
        {MPS_TABLE_GUID, "MPS", &mps_phys},
@@ -533,7 +533,6 @@ efi_init (void)
 
        if (efi_config_parse_tables(__va(efi_systab->tables),
                                    efi_systab->nr_tables,
-                                   sizeof(efi_config_table_t),
                                    arch_tables) != 0)
                return;
 

diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index f1033f7f9e39aae852c31abd894340486819d92e..47367f4d82d0a5c2dfacb7a97d07bafc18f43596 100644 (file)
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -60,7 +60,7 @@ static u64 efi_systab_phys __initdata;
 static unsigned long prop_phys = EFI_INVALID_TABLE_ADDR;
 static unsigned long uga_phys = EFI_INVALID_TABLE_ADDR;
 
-static efi_config_table_type_t arch_tables[] __initdata = {
+static const efi_config_table_type_t arch_tables[] __initconst = {
        {EFI_PROPERTIES_TABLE_GUID, "PROP", &prop_phys},
        {UGA_IO_PROTOCOL_GUID, "UGA", &uga_phys},
 #ifdef CONFIG_X86_UV
@@ -431,7 +431,7 @@ static int __init efi_systab_init(u64 phys)
        return 0;
 }
 
-static int __init efi_config_init(efi_config_table_type_t *arch_tables)
+static int __init efi_config_init(const efi_config_table_type_t *arch_tables)
 {
        void *config_tables;
        int sz, ret;
@@ -454,7 +454,7 @@ static int __init efi_config_init(efi_config_table_type_t *arch_tables)
                return -ENOMEM;
        }
 
-       ret = efi_config_parse_tables(config_tables, efi.systab->nr_tables, sz,
+       ret = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
                                      arch_tables);
 
        early_memunmap(config_tables, efi.systab->nr_tables * sz);

diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
index a656bfcd7e276a1c41eb975d7f4f33246cd170b2..d1f44c84784112e52d39126e74a22c57df60196e 100644 (file)
--- a/drivers/firmware/efi/arm-init.c
+++ b/drivers/firmware/efi/arm-init.c
@@ -55,7 +55,7 @@ static phys_addr_t efi_to_phys(unsigned long addr)
 
 static __initdata unsigned long screen_info_table = EFI_INVALID_TABLE_ADDR;
 
-static __initdata efi_config_table_type_t arch_tables[] = {
+static const efi_config_table_type_t arch_tables[] __initconst = {
        {LINUX_EFI_ARM_SCREEN_INFO_TABLE_GUID, NULL, &screen_info_table},
        {NULL_GUID, NULL, NULL}
 };
@@ -85,7 +85,7 @@ static void __init init_screen_info(void)
 
 static int __init uefi_init(void)
 {
-       void *config_tables;
+       efi_config_table_t *config_tables;
        size_t table_size;
        int retval;
 
@@ -118,7 +118,6 @@ static int __init uefi_init(void)
                goto out;
        }
        retval = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
-                                        sizeof(efi_config_table_t),
                                         arch_tables);
 
        if (!retval)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index 2bfd6c0806ce41c1062092a6fc84f08419468037..45de4c4a696b357f666de0e9244e31087d294442 100644 (file)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -460,7 +460,7 @@ void __init efi_mem_reserve(phys_addr_t addr, u64 size)
        efi_arch_mem_reserve(addr, size);
 }
 
-static __initdata efi_config_table_type_t common_tables[] = {
+static const efi_config_table_type_t common_tables[] __initconst = {
        {ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
        {ACPI_TABLE_GUID, "ACPI", &efi.acpi},
        {SMBIOS_TABLE_GUID, "SMBIOS", &efi.smbios},
@@ -477,9 +477,9 @@ static __initdata efi_config_table_type_t common_tables[] = {
        {NULL_GUID, NULL, NULL},
 };
 
-static __init int match_config_table(efi_guid_t *guid,
+static __init int match_config_table(const efi_guid_t *guid,
                                     unsigned long table,
-                                    efi_config_table_type_t *table_types)
+                                    const efi_config_table_type_t *table_types)
 {
        int i;
 
@@ -498,39 +498,38 @@ static __init int match_config_table(efi_guid_t *guid,
        return 0;
 }
 
-int __init efi_config_parse_tables(void *config_tables, int count, int sz,
-                                  efi_config_table_type_t *arch_tables)
+int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
+                                  int count,
+                                  const efi_config_table_type_t *arch_tables)
 {
-       void *tablep;
+       const efi_config_table_64_t *tbl64 = (void *)config_tables;
+       const efi_config_table_32_t *tbl32 = (void *)config_tables;
+       const efi_guid_t *guid;
+       unsigned long table;
        int i;
 
-       tablep = config_tables;
        pr_info("");
        for (i = 0; i < count; i++) {
-               efi_guid_t guid;
-               unsigned long table;
-
-               if (efi_enabled(EFI_64BIT)) {
-                       u64 table64;
-                       guid = ((efi_config_table_64_t *)tablep)->guid;
-                       table64 = ((efi_config_table_64_t *)tablep)->table;
-                       table = table64;
-#ifndef CONFIG_64BIT
-                       if (table64 >> 32) {
+               if (!IS_ENABLED(CONFIG_X86)) {
+                       guid = &config_tables[i].guid;
+                       table = (unsigned long)config_tables[i].table;
+               } else if (efi_enabled(EFI_64BIT)) {
+                       guid = &tbl64[i].guid;
+                       table = tbl64[i].table;
+
+                       if (IS_ENABLED(CONFIG_X86_32) &&
+                           tbl64[i].table > U32_MAX) {
                                pr_cont("\n");
                                pr_err("Table located above 4GB, disabling EFI.\n");
                                return -EINVAL;
                        }
-#endif
                } else {
-                       guid = ((efi_config_table_32_t *)tablep)->guid;
-                       table = ((efi_config_table_32_t *)tablep)->table;
+                       guid = &tbl32[i].guid;
+                       table = tbl32[i].table;
                }
 
-               if (!match_config_table(&guid, table, common_tables))
-                       match_config_table(&guid, table, arch_tables);
-
-               tablep += sz;
+               if (!match_config_table(guid, table, common_tables))
+                       match_config_table(guid, table, arch_tables);
        }
        pr_cont("\n");
        set_bit(EFI_CONFIG_TABLES, &efi.flags);

diff --git a/include/linux/efi.h b/include/linux/efi.h
index d61c25fd582421f7ec8af84ac9f584e7c5c3021b..99a7fcbe5e9bfc77d96ebe465ddee9997229d9c0 100644 (file)
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -613,8 +613,9 @@ extern void __init efi_esrt_init(void);
 #else
 static inline void efi_esrt_init(void) { }
 #endif
-extern int efi_config_parse_tables(void *config_tables, int count, int sz,
-                                  efi_config_table_type_t *arch_tables);
+extern int efi_config_parse_tables(const efi_config_table_t *config_tables,
+                                  int count,
+                                  const efi_config_table_type_t *arch_tables);
 extern int efi_systab_check_header(const efi_table_hdr_t *systab_hdr,
                                   int min_major_version);
 extern void efi_systab_report_header(const efi_table_hdr_t *systab_hdr,