efi: Add support for EFI_RT_PROPERTIES table

Take the newly introduced EFI_RT_PROPERTIES_TABLE configuration table
into account, which carries a mask of which EFI runtime services are
still functional after ExitBootServices() has been called by the OS.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

drivers/firmware/efi/efi.c

@@ -47,6 +47,7 @@ EXPORT_SYMBOL(efi);
 
 static unsigned long __ro_after_init rng_seed = EFI_INVALID_TABLE_ADDR;
 static unsigned long __initdata mem_reserve = EFI_INVALID_TABLE_ADDR;
+static unsigned long __initdata rt_prop = EFI_INVALID_TABLE_ADDR;
 
 struct mm_struct efi_mm = {
 	.mm_rb			= RB_ROOT,
@@ -449,6 +450,7 @@ static const efi_config_table_type_t common_tables[] __initconst = {
 	{LINUX_EFI_TPM_EVENT_LOG_GUID, "TPMEventLog", &efi.tpm_log},
 	{LINUX_EFI_TPM_FINAL_LOG_GUID, "TPMFinalLog", &efi.tpm_final_log},
 	{LINUX_EFI_MEMRESERVE_TABLE_GUID, "MEMRESERVE", &mem_reserve},
+	{EFI_RT_PROPERTIES_TABLE_GUID, "RTPROP", &rt_prop},
 #ifdef CONFIG_EFI_RCI2_TABLE
 	{DELLEMC_EFI_RCI2_TABLE_GUID, NULL, &rci2_table_phys},
 #endif
@@ -575,6 +577,16 @@ int __init efi_config_parse_tables(const efi_config_table_t *config_tables,
 		}
 	}
 
+	if (rt_prop != EFI_INVALID_TABLE_ADDR) {
+		efi_rt_properties_table_t *tbl;
+
+		tbl = early_memremap(rt_prop, sizeof(*tbl));
+		if (tbl) {
+			efi.runtime_supported_mask &= tbl->runtime_services_supported;
+			early_memunmap(tbl, sizeof(*tbl));
+		}
+	}
+
 	return 0;
 }
 

include/linux/efi.h

@@ -334,6 +334,7 @@ void efi_native_runtime_setup(void);
 #define EFI_TCG2_PROTOCOL_GUID			EFI_GUID(0x607f766c, 0x7455, 0x42be,  0x93, 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
 #define EFI_LOAD_FILE_PROTOCOL_GUID		EFI_GUID(0x56ec3091, 0x954c, 0x11d2,  0x8e, 0x3f, 0x00, 0xa0, 0xc9, 0x69, 0x72, 0x3b)
 #define EFI_LOAD_FILE2_PROTOCOL_GUID		EFI_GUID(0x4006c0c1, 0xfcb3, 0x403e,  0x99, 0x6d, 0x4a, 0x6c, 0x87, 0x24, 0xe0, 0x6d)
+#define EFI_RT_PROPERTIES_TABLE_GUID		EFI_GUID(0xeb66918a, 0x7eef, 0x402a,  0x84, 0x2e, 0x93, 0x1d, 0x21, 0xc3, 0x8a, 0xe9)
 
 #define EFI_IMAGE_SECURITY_DATABASE_GUID	EFI_GUID(0xd719b2cb, 0x3d3a, 0x4596,  0xa3, 0xbc, 0xda, 0xd0, 0x0e, 0x67, 0x65, 0x6f)
 #define EFI_SHIM_LOCK_GUID			EFI_GUID(0x605dab50, 0xe046, 0x4300,  0xab, 0xb6, 0x3d, 0xd8, 0x10, 0xdd, 0x8b, 0x23)
@@ -486,6 +487,14 @@ typedef struct {
 #define EFI_PROPERTIES_TABLE_VERSION	0x00010000
 #define EFI_PROPERTIES_RUNTIME_MEMORY_PROTECTION_NON_EXECUTABLE_PE_DATA	0x1
 
+typedef struct {
+	u16 version;
+	u16 length;
+	u32 runtime_services_supported;
+} efi_rt_properties_table_t;
+
+#define EFI_RT_PROPERTIES_TABLE_VERSION	0x1
+
 #define EFI_INVALID_TABLE_ADDR		(~0UL)
 
 typedef struct {