efi/x86: Make fw_vendor, config_table and runtime sysfs nodes x86 specific

There is some code that exposes physical addresses of certain parts of
the EFI firmware implementation via sysfs nodes. These nodes are only
used on x86, and are of dubious value to begin with, so let's move
their handling into the x86 arch code.

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

4 files changed, 53 insertions, 15 deletions

diff --git a/arch/x86/include/asm/efi.h b/arch/x86/include/asm/efi.h
index ee867f01b2f6..78fc28da2e29 100644
--- a/arch/x86/include/asm/efi.h
+++ b/arch/x86/include/asm/efi.h
@@ -10,6 +10,8 @@
 #include <asm/mmu_context.h>
 #include <linux/build_bug.h>
 
+extern unsigned long efi_fw_vendor, efi_config_table;
+
 /*
  * We map the EFI regions needed for runtime services non-contiguously,
  * with preserved alignment on virtual addresses starting from -4G down
diff --git a/arch/x86/kernel/kexec-bzimage64.c b/arch/x86/kernel/kexec-bzimage64.c
index f400678bd345..db6578d45157 100644
--- a/arch/x86/kernel/kexec-bzimage64.c
+++ b/arch/x86/kernel/kexec-bzimage64.c
@@ -141,8 +141,8 @@ prepare_add_efi_setup_data(struct boot_params *params,
 	struct setup_data *sd = (void *)params + efi_setup_data_offset;
 	struct efi_setup_data *esd = (void *)sd + sizeof(struct setup_data);
 
-	esd->fw_vendor = efi.fw_vendor;
-	esd->tables = efi.config_table;
+	esd->fw_vendor = efi_fw_vendor;
+	esd->tables = efi_config_table;
 	esd->smbios = efi.smbios;
 
 	sd->type = SETUP_EFI;
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 7d932452a40f..6fa412e156c7 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -59,6 +59,9 @@ 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 unsigned long efi_runtime, efi_nr_tables;
+
+unsigned long efi_fw_vendor, efi_config_table;
 
 static const efi_config_table_type_t arch_tables[] __initconst = {
 	{EFI_PROPERTIES_TABLE_GUID, "PROP", &prop_phys},
@@ -78,9 +81,9 @@ static const unsigned long * const efi_tables[] = {
 #ifdef CONFIG_X86_UV
 	&uv_systab_phys,
 #endif
-	&efi.fw_vendor,
-	&efi.runtime,
-	&efi.config_table,
+	&efi_fw_vendor,
+	&efi_runtime,
+	&efi_config_table,
 	&efi.esrt,
 	&prop_phys,
 	&efi_mem_attr_table,
@@ -434,7 +437,7 @@ static int __init efi_config_init(const efi_config_table_type_t *arch_tables)
 	void *config_tables;
 	int sz, ret;
 
-	if (efi.systab->nr_tables == 0)
+	if (efi_nr_tables == 0)
 		return 0;
 
 	if (efi_enabled(EFI_64BIT))
@@ -445,17 +448,16 @@ static int __init efi_config_init(const efi_config_table_type_t *arch_tables)
 	/*
 	 * Let's see what config tables the firmware passed to us.
 	 */
-	config_tables = early_memremap(efi.systab->tables,
-				       efi.systab->nr_tables * sz);
+	config_tables = early_memremap(efi_config_table, efi_nr_tables * sz);
 	if (config_tables == NULL) {
 		pr_err("Could not map Configuration table!\n");
 		return -ENOMEM;
 	}
 
-	ret = efi_config_parse_tables(config_tables, efi.systab->nr_tables,
+	ret = efi_config_parse_tables(config_tables, efi_nr_tables,
 				      arch_tables);
 
-	early_memunmap(config_tables, efi.systab->nr_tables * sz);
+	early_memunmap(config_tables, efi_nr_tables * sz);
 	return ret;
 }
 
@@ -474,11 +476,12 @@ void __init efi_init(void)
 	if (efi_systab_init(efi_systab_phys))
 		return;
 
-	efi.config_table = (unsigned long)efi.systab->tables;
-	efi.fw_vendor	 = (unsigned long)efi.systab->fw_vendor;
-	efi.runtime	 = (unsigned long)efi.systab->runtime;
+	efi_config_table = (unsigned long)efi.systab->tables;
+	efi_nr_tables    = efi.systab->nr_tables;
+	efi_fw_vendor    = (unsigned long)efi.systab->fw_vendor;
+	efi_runtime      = (unsigned long)efi.systab->runtime;
 
-	if (efi_reuse_config(efi.systab->tables, efi.systab->nr_tables))
+	if (efi_reuse_config(efi_config_table, efi_nr_tables))
 		return;
 
 	if (efi_config_init(arch_tables))
@@ -1023,3 +1026,36 @@ char *efi_systab_show_arch(char *str)
 		str += sprintf(str, "UGA=0x%lx\n", uga_phys);
 	return str;
 }
+
+#define EFI_FIELD(var) efi_ ## var
+
+#define EFI_ATTR_SHOW(name) \
+static ssize_t name##_show(struct kobject *kobj, \
+				struct kobj_attribute *attr, char *buf) \
+{ \
+	return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \
+}
+
+EFI_ATTR_SHOW(fw_vendor);
+EFI_ATTR_SHOW(runtime);
+EFI_ATTR_SHOW(config_table);
+
+struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor);
+struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime);
+struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table);
+
+umode_t efi_attr_is_visible(struct kobject *kobj, struct attribute *attr, int n)
+{
+	if (attr == &efi_attr_fw_vendor.attr) {
+		if (efi_enabled(EFI_PARAVIRT) ||
+				efi_fw_vendor == EFI_INVALID_TABLE_ADDR)
+			return 0;
+	} else if (attr == &efi_attr_runtime.attr) {
+		if (efi_runtime == EFI_INVALID_TABLE_ADDR)
+			return 0;
+	} else if (attr == &efi_attr_config_table.attr) {
+		if (efi_config_table == EFI_INVALID_TABLE_ADDR)
+			return 0;
+	}
+	return attr->mode;
+}
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 88d32c06cffa..b0e0161e2e8e 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -537,7 +537,7 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
 		goto out_memremap;
 	}
 
-	for (i = 0; i < efi.systab->nr_tables; i++) {
+	for (i = 0; i < nr_tables; i++) {
 		efi_guid_t guid;
 
 		guid = ((efi_config_table_64_t *)p)->guid;