[RFC PATCH v4 12/28] efi: Add an EFI table address match function

[Tom Lendacky]

This patch adds support that will determine if a supplied physical address
matches the address of an EFI table.

Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx>
---
 drivers/firmware/efi/efi.c |   33 +++++++++++++++++++++++++++++++++
 include/linux/efi.h        |    7 +++++++
 2 files changed, 40 insertions(+)

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index e7d4040..e8dbcdf 100644
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -55,6 +55,25 @@ struct efi __read_mostly efi = {
 };
 EXPORT_SYMBOL(efi);
 
+static unsigned long *efi_tables[] = {
+	&efi.mps,
+	&efi.acpi,
+	&efi.acpi20,
+	&efi.smbios,
+	&efi.smbios3,
+	&efi.sal_systab,
+	&efi.boot_info,
+	&efi.hcdp,
+	&efi.uga,
+	&efi.uv_systab,
+	&efi.fw_vendor,
+	&efi.runtime,
+	&efi.config_table,
+	&efi.esrt,
+	&efi.properties_table,
+	&efi.mem_attr_table,
+};
+
 static bool disable_runtime;
 static int __init setup_noefi(char *arg)
 {
@@ -855,6 +874,20 @@ int efi_status_to_err(efi_status_t status)
 	return err;
 }
 
+bool efi_table_address_match(unsigned long phys_addr)
+{
+	unsigned int i;
+
+	if (phys_addr == EFI_INVALID_TABLE_ADDR)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(efi_tables); i++)
+		if (*(efi_tables[i]) == phys_addr)
+			return true;
+
+	return false;
+}
+
 #ifdef CONFIG_KEXEC
 static int update_efi_random_seed(struct notifier_block *nb,
 				  unsigned long code, void *unused)
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 94d34e0..7694b23 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -1079,6 +1079,8 @@ static inline bool efi_enabled(int feature)
 	return test_bit(feature, &efi.flags) != 0;
 }
 extern void efi_reboot(enum reboot_mode reboot_mode, const char *__unused);
+
+extern bool efi_table_address_match(unsigned long phys_addr);
 #else
 static inline bool efi_enabled(int feature)
 {
@@ -1092,6 +1094,11 @@ static inline bool efi_enabled(int feature)
 {
 	return false;
 }
+
+static inline bool efi_table_address_match(unsigned long phys_addr)
+{
+	return false;
+}
 #endif
 
 extern int efi_status_to_err(efi_status_t status);