efi/x86: limit EFI old memory map to SGI UV machines

index 0a58468a7203..86169a24b0d8 100644
@@ -20,13 +20,16 @@
  * This is the main reason why we're doing stable VA mappings for RT
  * services.
  *
- * This flag is used in conjunction with a chicken bit called
- * "efi=old_map" which can be used as a fallback to the old runtime
- * services mapping method in case there's some b0rkage with a
- * particular EFI implementation (haha, it is hard to hold up the
- * sarcasm here...).
+ * SGI UV1 machines are known to be incompatible with this scheme, so we
+ * provide an opt-out for these machines via a DMI quirk that sets the
+ * attribute below.
  */
-#define EFI_OLD_MEMMAP		EFI_ARCH_1
+#define EFI_UV1_MEMMAP         EFI_ARCH_1
+
+static inline bool efi_have_uv1_memmap(void)
+{
+	return IS_ENABLED(CONFIG_X86_UV) && efi_enabled(EFI_UV1_MEMMAP);
+}
 
 #define EFI32_LOADER_SIGNATURE	"EL32"
 #define EFI64_LOADER_SIGNATURE	"EL64"

@@ -119,7 +122,7 @@ struct efi_scratch {
 	kernel_fpu_begin();						\
 	firmware_restrict_branch_speculation_start();			\
 									\
-	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+	if (!efi_have_uv1_memmap())					\
 		efi_switch_mm(&efi_mm);					\
 })
 

@@ -128,7 +131,7 @@ struct efi_scratch {
 
 #define arch_efi_call_virt_teardown()					\
 ({									\
-	if (!efi_enabled(EFI_OLD_MEMMAP))				\
+	if (!efi_have_uv1_memmap())					\
 		efi_switch_mm(efi_scratch.prev_mm);			\
 									\
 	firmware_restrict_branch_speculation_end();			\

@@ -172,6 +175,8 @@ extern void efi_delete_dummy_variable(void);
 extern void efi_switch_mm(struct mm_struct *mm);
 extern void efi_recover_from_page_fault(unsigned long phys_addr);
 extern void efi_free_boot_services(void);
+extern pgd_t * __init efi_uv1_memmap_phys_prolog(void);
+extern void __init efi_uv1_memmap_phys_epilog(pgd_t *save_pgd);
 
 struct efi_setup_data {
 	u64 fw_vendor;

@@ -203,10 +208,7 @@ static inline bool efi_runtime_supported(void)
 	if (IS_ENABLED(CONFIG_X86_64) == efi_enabled(EFI_64BIT))
 		return true;
 
-	if (IS_ENABLED(CONFIG_EFI_MIXED) && !efi_enabled(EFI_OLD_MEMMAP))
-		return true;
-
-	return false;
+	return IS_ENABLED(CONFIG_EFI_MIXED);
 }
 
 extern void parse_efi_setup(u64 phys_addr, u32 data_len);

index d2f4e706a428..f293d872602a 100644
@@ -177,7 +177,7 @@ setup_efi_state(struct boot_params *params, unsigned long params_load_addr,
 	 * acpi_rsdp=<addr> on kernel command line to make second kernel boot
 	 * without efi.
 	 */
-	if (efi_enabled(EFI_OLD_MEMMAP))
+	if (efi_have_uv1_memmap())
 		return 0;
 
 	params->secure_boot = boot_params.secure_boot;

index b931c4bea284..4e46d2d24352 100644
@@ -497,6 +497,8 @@ void __init efi_init(void)
 		efi_print_memmap();
 }
 
+#if defined(CONFIG_X86_32) || defined(CONFIG_X86_UV)
+
 void __init efi_set_executable(efi_memory_desc_t *md, bool executable)
 {
 	u64 addr, npages;

@@ -561,6 +563,8 @@ void __init old_map_region(efi_memory_desc_t *md)
 		       (unsigned long long)md->phys_addr);
 }
 
+#endif
+
 /* Merge contiguous regions of the same type and attribute */
 static void __init efi_merge_regions(void)
 {

@@ -659,7 +663,7 @@ static inline void *efi_map_next_entry_reverse(void *entry)
  */
 static void *efi_map_next_entry(void *entry)
 {
-	if (!efi_enabled(EFI_OLD_MEMMAP) && efi_enabled(EFI_64BIT)) {
+	if (!efi_have_uv1_memmap() && efi_enabled(EFI_64BIT)) {
 		/*
 		 * Starting in UEFI v2.5 the EFI_PROPERTIES_TABLE
 		 * config table feature requires us to map all entries

@@ -791,11 +795,11 @@ static void __init kexec_enter_virtual_mode(void)
 
 	/*
 	 * We don't do virtual mode, since we don't do runtime services, on
-	 * non-native EFI. With efi=old_map, we don't do runtime services in
+	 * non-native EFI. With the UV1 memmap, we don't do runtime services in
 	 * kexec kernel because in the initial boot something else might
 	 * have been mapped at these virtual addresses.
 	 */
-	if (efi_is_mixed() || efi_enabled(EFI_OLD_MEMMAP)) {
+	if (efi_is_mixed() || efi_have_uv1_memmap()) {
 		efi_memmap_unmap();
 		clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
 		return;

@@ -861,9 +865,9 @@ static void __init kexec_enter_virtual_mode(void)
  *
  * The old method which used to update that memory descriptor with the
  * virtual address obtained from ioremap() is still supported when the
- * kernel is booted with efi=old_map on its command line. Same old
- * method enabled the runtime services to be called without having to
- * thunk back into physical mode for every invocation.
+ * kernel is booted on SG1 UV1 hardware. Same old method enabled the
+ * runtime services to be called without having to thunk back into
+ * physical mode for every invocation.
  *
  * The new method does a pagetable switch in a preemption-safe manner
  * so that we're in a different address space when calling a runtime

@@ -976,20 +980,6 @@ void __init efi_enter_virtual_mode(void)
 	efi_dump_pagetable();
 }
 
-static int __init arch_parse_efi_cmdline(char *str)
-{
-	if (!str) {
-		pr_warn("need at least one option\n");
-		return -EINVAL;
-	}
-
-	if (parse_option_str(str, "old_map"))
-		set_bit(EFI_OLD_MEMMAP, &efi.flags);
-
-	return 0;
-}
-early_param("efi", arch_parse_efi_cmdline);
-
 bool efi_is_table_address(unsigned long phys_addr)
 {
 	unsigned int i;

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index eb421cb35108..fe46ddf6c761 100644
@@ -384,10 +384,10 @@ static void __init efi_unmap_pages(efi_memory_desc_t *md)
 
 	/*
 	 * To Do: Remove this check after adding functionality to unmap EFI boot
-	 * services code/data regions from direct mapping area because
-	 * "efi=old_map" maps EFI regions in swapper_pg_dir.
+	 * services code/data regions from direct mapping area because the UV1
+	 * memory map maps EFI regions in swapper_pg_dir.
 	 */
-	if (efi_enabled(EFI_OLD_MEMMAP))
+	if (efi_have_uv1_memmap())
 		return;
 
 	/*

@@ -558,7 +558,7 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
 	return ret;
 }
 
-static const struct dmi_system_id sgi_uv1_dmi[] = {
+static const struct dmi_system_id sgi_uv1_dmi[] __initconst = {
 	{ NULL, "SGI UV1",
 		{	DMI_MATCH(DMI_PRODUCT_NAME,	"Stoutland Platform"),
 			DMI_MATCH(DMI_PRODUCT_VERSION,	"1.0"),

@@ -581,8 +581,15 @@ void __init efi_apply_memmap_quirks(void)
 	}
 
 	/* UV2+ BIOS has a fix for this issue.  UV1 still needs the quirk. */
-	if (dmi_check_system(sgi_uv1_dmi))
-		set_bit(EFI_OLD_MEMMAP, &efi.flags);
+	if (dmi_check_system(sgi_uv1_dmi)) {
+		if (IS_ENABLED(CONFIG_X86_UV)) {
+			set_bit(EFI_UV1_MEMMAP, &efi.flags);
+		} else {
+			pr_warn("EFI runtime disabled, needs CONFIG_X86_UV=y on UV1\n");
+			clear_bit(EFI_RUNTIME_SERVICES, &efi.flags);
+			efi_memmap_unmap();
+		}
+	}
 }
 
 /*

@@ -720,7 +727,7 @@ void efi_recover_from_page_fault(unsigned long phys_addr)
 	/*
 	 * Make sure that an efi runtime service caused the page fault.
 	 * "efi_mm" cannot be used to check if the page fault had occurred
-	 * in the firmware context because efi=old_map doesn't use efi_pgd.
+	 * in the firmware context because the UV1 memmap doesn't use efi_pgd.
 	 */
 	if (efi_rts_work.efi_rts_id == EFI_NONE)
 		return;

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