Commit 0a23ebc6 authored by Junichi Nomura's avatar Junichi Nomura Committed by Borislav Petkov
Browse files

x86/boot: Use efi_setup_data for searching RSDP on kexec-ed kernels 



Commit

  3a63f70b ("x86/boot: Early parse RSDP and save it in boot_params")

broke kexec boot on EFI systems. efi_get_rsdp_addr() in the early
parsing code tries to search RSDP from the EFI tables but that will
crash because the table address is virtual when the kernel was booted by
kexec (set_virtual_address_map() has run in the first kernel and cannot
be run again in the second kernel).

In the case of kexec, the physical address of EFI tables is provided via
efi_setup_data in boot_params, which is set up by kexec(1).

Factor out the table parsing code and use different pointers depending
on whether the kernel is booted by kexec or not.

 [ bp: Massage. ]

Fixes: 3a63f70b ("x86/boot: Early parse RSDP and save it in boot_params")
Signed-off-by: default avatarJun'ichi Nomura <j-nomura@ce.jp.nec.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Tested-by: default avatarDirk van der Merwe <dirk.vandermerwe@netronome.com>
Cc: Chao Fan <fanc.fnst@cn.fujitsu.com>
Cc: Dave Young <dyoung@redhat.com>
Link: https://lkml.kernel.org/r/20190408231011.GA5402@jeru.linux.bs1.fc.nec.co.jp
parent 6bbeb276

arch/x86/boot/compressed/acpi.c

+107 −36
Original line number Diff line number Diff line
@@ -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();

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