Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Thomas Gleixner:
 "Assorted updates to kexec/kdump:

   - Proper kexec support for 4/5-level paging and jumping from a
     5-level to a 4-level paging kernel.

   - Make the EFI support for kexec/kdump more robust

   - Enforce that the GDT is properly aligned instead of getting the
     alignment by chance"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kdump/64: Restrict kdump kernel reservation to <64TB
  x86/kexec/64: Prevent kexec from 5-level paging to a 4-level only kernel
  x86/boot: Add xloadflags bits to check for 5-level paging support
  x86/boot: Make the GDT 8-byte aligned
  x86/kexec: Add the ACPI NVS region to the ident map
  x86/boot: Call get_rsdp_addr() after console_init()
  Revert "x86/boot: Disable RSDP parsing temporarily"
  x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels
  x86/kexec: Add the EFI system tables and ACPI tables to the ident map

arch/x86/boot/compressed/acpi.c

@@ -44,17 +44,109 @@ static acpi_physical_address get_acpi_rsdp(void)
 	return addr;
 }
 
-/* Search EFI system tables for RSDP. */
-static acpi_physical_address efi_get_rsdp_addr(void)
+/*
+ * Search EFI system tables for RSDP.  If both ACPI_20_TABLE_GUID and
+ * ACPI_TABLE_GUID are found, take the former, which has more features.
+ */
+static acpi_physical_address
+__efi_get_rsdp_addr(unsigned long config_tables, unsigned int nr_tables,
+		    bool efi_64)
 {
 	acpi_physical_address rsdp_addr = 0;
 
 #ifdef CONFIG_EFI
-	unsigned long systab, systab_tables, config_tables;
+	int i;
+
+	/* Get EFI tables from systab. */
+	for (i = 0; i < nr_tables; i++) {
+		acpi_physical_address table;
+		efi_guid_t guid;
+
+		if (efi_64) {
+			efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables + i;
+
+			guid  = tbl->guid;
+			table = tbl->table;
+
+			if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
+				debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
+				return 0;
+			}
+		} else {
+			efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables + i;
+
+			guid  = tbl->guid;
+			table = tbl->table;
+		}
+
+		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
+			rsdp_addr = table;
+		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
+			return table;
+	}
+#endif
+	return rsdp_addr;
+}
+
+/* EFI/kexec support is 64-bit only. */
+#ifdef CONFIG_X86_64
+static struct efi_setup_data *get_kexec_setup_data_addr(void)
+{
+	struct setup_data *data;
+	u64 pa_data;
+
+	pa_data = boot_params->hdr.setup_data;
+	while (pa_data) {
+		data = (struct setup_data *)pa_data;
+		if (data->type == SETUP_EFI)
+			return (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));
+
+		pa_data = data->next;
+	}
+	return NULL;
+}
+
+static acpi_physical_address kexec_get_rsdp_addr(void)
+{
+	efi_system_table_64_t *systab;
+	struct efi_setup_data *esd;
+	struct efi_info *ei;
+	char *sig;
+
+	esd = (struct efi_setup_data *)get_kexec_setup_data_addr();
+	if (!esd)
+		return 0;
+
+	if (!esd->tables) {
+		debug_putstr("Wrong kexec SETUP_EFI data.\n");
+		return 0;
+	}
+
+	ei = &boot_params->efi_info;
+	sig = (char *)&ei->efi_loader_signature;
+	if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) {
+		debug_putstr("Wrong kexec EFI loader signature.\n");
+		return 0;
+	}
+
+	/* Get systab from boot params. */
+	systab = (efi_system_table_64_t *) (ei->efi_systab | ((__u64)ei->efi_systab_hi << 32));
+	if (!systab)
+		error("EFI system table not found in kexec boot_params.");
+
+	return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables, true);
+}
+#else
+static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
+#endif /* CONFIG_X86_64 */
+
+static acpi_physical_address efi_get_rsdp_addr(void)
+{
+#ifdef CONFIG_EFI
+	unsigned long systab, config_tables;
 	unsigned int nr_tables;
 	struct efi_info *ei;
 	bool efi_64;
-	int size, i;
 	char *sig;
 
 	ei = &boot_params->efi_info;
@@ -88,49 +180,20 @@ static acpi_physical_address efi_get_rsdp_addr(void)
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
-		size		= sizeof(efi_config_table_64_t);
 	} else {
 		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab;
 
 		config_tables	= stbl->tables;
 		nr_tables	= stbl->nr_tables;
-		size		= sizeof(efi_config_table_32_t);
 	}
 
 	if (!config_tables)
 		error("EFI config tables not found.");
 
-	/* Get EFI tables from systab. */
-	for (i = 0; i < nr_tables; i++) {
-		acpi_physical_address table;
-		efi_guid_t guid;
-
-		config_tables += size;
-
-		if (efi_64) {
-			efi_config_table_64_t *tbl = (efi_config_table_64_t *)config_tables;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-
-			if (!IS_ENABLED(CONFIG_X86_64) && table >> 32) {
-				debug_putstr("Error getting RSDP address: EFI config table located above 4GB.\n");
+	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);
+#else
 	return 0;
-			}
-		} else {
-			efi_config_table_32_t *tbl = (efi_config_table_32_t *)config_tables;
-
-			guid  = tbl->guid;
-			table = tbl->table;
-		}
-
-		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))
-			rsdp_addr = table;
-		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))
-			return table;
-	}
 #endif
-	return rsdp_addr;
 }
 
 static u8 compute_checksum(u8 *buffer, u32 length)
@@ -220,6 +283,14 @@ acpi_physical_address get_rsdp_addr(void)
 	if (!pa)
 		pa = boot_params->acpi_rsdp_addr;
 
+	/*
+	 * Try to get EFI data from setup_data. This can happen when we're a
+	 * kexec'ed kernel and kexec(1) has passed all the required EFI info to
+	 * us.
+	 */
+	if (!pa)
+		pa = kexec_get_rsdp_addr();
+
 	if (!pa)
 		pa = efi_get_rsdp_addr();
 

arch/x86/boot/compressed/head_64.S

@@ -659,6 +659,7 @@ no_longmode:
 gdt64:
 	.word	gdt_end - gdt
 	.quad   0
+	.balign	8
 gdt:
 	.word	gdt_end - gdt
 	.long	gdt

arch/x86/boot/compressed/misc.c

@@ -351,9 +351,6 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	/* Clear flags intended for solely in-kernel use. */
 	boot_params->hdr.loadflags &= ~KASLR_FLAG;
 
-	/* Save RSDP address for later use. */
-	/* boot_params->acpi_rsdp_addr = get_rsdp_addr(); */
-
 	sanitize_boot_params(boot_params);
 
 	if (boot_params->screen_info.orig_video_mode == 7) {
@@ -368,6 +365,14 @@ asmlinkage __visible void *extract_kernel(void *rmode, memptr heap,
 	cols = boot_params->screen_info.orig_video_cols;
 
 	console_init();
+
+	/*
+	 * Save RSDP address for later use. Have this after console_init()
+	 * so that early debugging output from the RSDP parsing code can be
+	 * collected.
+	 */
+	boot_params->acpi_rsdp_addr = get_rsdp_addr();
+
 	debug_putstr("early console in extract_kernel\n");
 
 	free_mem_ptr     = heap;	/* Heap */

arch/x86/boot/header.S

@@ -419,7 +419,17 @@ xloadflags:
 # define XLF4 0
 #endif
 
-			.word XLF0 | XLF1 | XLF23 | XLF4
+#ifdef CONFIG_X86_64
+#ifdef CONFIG_X86_5LEVEL
+#define XLF56 (XLF_5LEVEL|XLF_5LEVEL_ENABLED)
+#else
+#define XLF56 XLF_5LEVEL
+#endif
+#else
+#define XLF56 0
+#endif
+
+			.word XLF0 | XLF1 | XLF23 | XLF4 | XLF56
 
 cmdline_size:   .long   COMMAND_LINE_SIZE-1     #length of the command line,
                                                 #added with boot protocol

arch/x86/include/uapi/asm/bootparam.h

@@ -29,6 +29,8 @@
 #define XLF_EFI_HANDOVER_32		(1<<2)
 #define XLF_EFI_HANDOVER_64		(1<<3)
 #define XLF_EFI_KEXEC			(1<<4)
+#define XLF_5LEVEL			(1<<5)
+#define XLF_5LEVEL_ENABLED		(1<<6)
 
 #ifndef __ASSEMBLY__
 

arch/x86/kernel/kexec-bzimage64.c

@@ -319,6 +319,11 @@ static int bzImage64_probe(const char *buf, unsigned long len)
 		return ret;
 	}
 
+	if (!(header->xloadflags & XLF_5LEVEL) && pgtable_l5_enabled()) {
+		pr_err("bzImage cannot handle 5-level paging mode.\n");
+		return ret;
+	}
+
 	/* I've got a bzImage */
 	pr_debug("It's a relocatable bzImage64\n");
 	ret = 0;

arch/x86/kernel/machine_kexec_64.c

@@ -16,6 +16,7 @@
 #include <linux/io.h>
 #include <linux/suspend.h>
 #include <linux/vmalloc.h>
+#include <linux/efi.h>
 
 #include <asm/init.h>
 #include <asm/pgtable.h>
@@ -27,6 +28,55 @@
 #include <asm/setup.h>
 #include <asm/set_memory.h>
 
+#ifdef CONFIG_ACPI
+/*
+ * Used while adding mapping for ACPI tables.
+ * Can be reused when other iomem regions need be mapped
+ */
+struct init_pgtable_data {
+	struct x86_mapping_info *info;
+	pgd_t *level4p;
+};
+
+static int mem_region_callback(struct resource *res, void *arg)
+{
+	struct init_pgtable_data *data = arg;
+	unsigned long mstart, mend;
+
+	mstart = res->start;
+	mend = mstart + resource_size(res) - 1;
+
+	return kernel_ident_mapping_init(data->info, data->level4p, mstart, mend);
+}
+
+static int
+map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p)
+{
+	struct init_pgtable_data data;
+	unsigned long flags;
+	int ret;
+
+	data.info = info;
+	data.level4p = level4p;
+	flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+
+	ret = walk_iomem_res_desc(IORES_DESC_ACPI_TABLES, flags, 0, -1,
+				  &data, mem_region_callback);
+	if (ret && ret != -EINVAL)
+		return ret;
+
+	/* ACPI tables could be located in ACPI Non-volatile Storage region */
+	ret = walk_iomem_res_desc(IORES_DESC_ACPI_NV_STORAGE, flags, 0, -1,
+				  &data, mem_region_callback);
+	if (ret && ret != -EINVAL)
+		return ret;
+
+	return 0;
+}
+#else
+static int map_acpi_tables(struct x86_mapping_info *info, pgd_t *level4p) { return 0; }
+#endif
+
 #ifdef CONFIG_KEXEC_FILE
 const struct kexec_file_ops * const kexec_file_loaders[] = {
 		&kexec_bzImage64_ops,
@@ -34,6 +84,31 @@ const struct kexec_file_ops * const kexec_file_loaders[] = {
 };
 #endif
 
+static int
+map_efi_systab(struct x86_mapping_info *info, pgd_t *level4p)
+{
+#ifdef CONFIG_EFI
+	unsigned long mstart, mend;
+
+	if (!efi_enabled(EFI_BOOT))
+		return 0;
+
+	mstart = (boot_params.efi_info.efi_systab |
+			((u64)boot_params.efi_info.efi_systab_hi<<32));
+
+	if (efi_enabled(EFI_64BIT))
+		mend = mstart + sizeof(efi_system_table_64_t);
+	else
+		mend = mstart + sizeof(efi_system_table_32_t);
+
+	if (!mstart)
+		return 0;
+
+	return kernel_ident_mapping_init(info, level4p, mstart, mend);
+#endif
+	return 0;
+}
+
 static void free_transition_pgtable(struct kimage *image)
 {
 	free_page((unsigned long)image->arch.p4d);
@@ -157,6 +232,18 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
 			return result;
 	}
 
+	/*
+	 * Prepare EFI systab and ACPI tables for kexec kernel since they are
+	 * not covered by pfn_mapped.
+	 */
+	result = map_efi_systab(&info, level4p);
+	if (result)
+		return result;
+
+	result = map_acpi_tables(&info, level4p);
+	if (result)
+		return result;
+
 	return init_transition_pgtable(image, level4p);
 }
 

arch/x86/kernel/setup.c

@@ -453,15 +453,24 @@ static void __init memblock_x86_reserve_range_setup_data(void)
 #define CRASH_ALIGN		SZ_16M
 
 /*
- * Keep the crash kernel below this limit.  On 32 bits earlier kernels
- * would limit the kernel to the low 512 MiB due to mapping restrictions.
+ * Keep the crash kernel below this limit.
+ *
+ * On 32 bits earlier kernels would limit the kernel to the low 512 MiB
+ * due to mapping restrictions.
+ *
+ * On 64bit, kdump kernel need be restricted to be under 64TB, which is
+ * the upper limit of system RAM in 4-level paing mode. Since the kdump
+ * jumping could be from 5-level to 4-level, the jumping will fail if
+ * kernel is put above 64TB, and there's no way to detect the paging mode
+ * of the kernel which will be loaded for dumping during the 1st kernel
+ * bootup.
  */
 #ifdef CONFIG_X86_32
 # define CRASH_ADDR_LOW_MAX	SZ_512M
 # define CRASH_ADDR_HIGH_MAX	SZ_512M
 #else
 # define CRASH_ADDR_LOW_MAX	SZ_4G
-# define CRASH_ADDR_HIGH_MAX	MAXMEM
+# define CRASH_ADDR_HIGH_MAX	SZ_64T
 #endif
 
 static int __init reserve_crashkernel_low(void)

include/linux/sizes.h

@@ -44,5 +44,6 @@
 #define SZ_2G				0x80000000
 
 #define SZ_4G				_AC(0x100000000, ULL)
+#define SZ_64T				_AC(0x400000000000, ULL)
 
 #endif /* __LINUX_SIZES_H__ */