Commit dee602dd authored by Michael Roth's avatar Michael Roth Committed by Borislav Petkov
Browse files

x86/compressed/acpi: Move EFI vendor table lookup to helper 



Future patches for SEV-SNP-validated CPUID will also require early
parsing of the EFI configuration. Incrementally move the related code
into a set of helpers that can be re-used for that purpose.

  [ bp: Unbreak unnecessarily broken lines. ]

Signed-off-by: default avatarMichael Roth <michael.roth@amd.com>
Signed-off-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-28-brijesh.singh@amd.com
parent 61c14ced

arch/x86/boot/compressed/acpi.c

+23 −45
Original line number Diff line number Diff line
@@ -20,48 +20,31 @@ 
 */

struct mem_vector immovable_mem[MAX_NUMNODES*2];



/*

 * 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)

__efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len)

{

	acpi_physical_address rsdp_addr = 0;



#ifdef CONFIG_EFI

	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;

		}

	unsigned long rsdp_addr;

	int ret;



		if (!(efi_guidcmp(guid, ACPI_TABLE_GUID)))

			rsdp_addr = table;

		else if (!(efi_guidcmp(guid, ACPI_20_TABLE_GUID)))

			return table;

	}

	/*

	 * Search EFI system tables for RSDP. Preferred is ACPI_20_TABLE_GUID to

	 * ACPI_TABLE_GUID because it has more features.

	 */

	rsdp_addr = efi_find_vendor_table(boot_params, cfg_tbl_pa, cfg_tbl_len,

					  ACPI_20_TABLE_GUID);

	if (rsdp_addr)

		return (acpi_physical_address)rsdp_addr;



	/* No ACPI_20_TABLE_GUID found, fallback to ACPI_TABLE_GUID. */

	rsdp_addr = efi_find_vendor_table(boot_params, cfg_tbl_pa, cfg_tbl_len,

					  ACPI_TABLE_GUID);

	if (rsdp_addr)

		return (acpi_physical_address)rsdp_addr;



	debug_putstr("Error getting RSDP address.\n");

#endif

	return rsdp_addr;

	return 0;

}



/* EFI/kexec support is 64-bit only. */
@@ -109,7 +92,7 @@ static acpi_physical_address kexec_get_rsdp_addr(void) 
	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);

	return __efi_get_rsdp_addr((unsigned long)esd->tables, systab->nr_tables);

}

#else

static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; }
@@ -123,15 +106,10 @@ static acpi_physical_address efi_get_rsdp_addr(void) 
	unsigned long systab_pa;

	unsigned int nr_tables;

	enum efi_type et;

	bool efi_64;

	int ret;



	et = efi_get_type(boot_params);

	if (et == EFI_TYPE_64)

		efi_64 = true;

	else if (et == EFI_TYPE_32)

		efi_64 = false;

	else

	if (et == EFI_TYPE_NONE)

		return 0;



	systab_pa = efi_get_system_table(boot_params);
@@ -142,7 +120,7 @@ static acpi_physical_address efi_get_rsdp_addr(void) 
	if (ret || !cfg_tbl_pa)

		error("EFI config table not found.");



	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len, efi_64);

	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len);

#else

	return 0;

#endif

arch/x86/boot/compressed/efi.c

+70 −0
Original line number Diff line number Diff line
@@ -120,3 +120,73 @@ int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa, 


	return 0;

}



/* Get vendor table address/guid from EFI config table at the given index */

static int get_vendor_table(void *cfg_tbl, unsigned int idx,

			    unsigned long *vendor_tbl_pa,

			    efi_guid_t *vendor_tbl_guid,

			    enum efi_type et)

{

	if (et == EFI_TYPE_64) {

		efi_config_table_64_t *tbl_entry = (efi_config_table_64_t *)cfg_tbl + idx;



		if (!IS_ENABLED(CONFIG_X86_64) && tbl_entry->table >> 32) {

			debug_putstr("Error: EFI config table entry located above 4GB.\n");

			return -EINVAL;

		}



		*vendor_tbl_pa = tbl_entry->table;

		*vendor_tbl_guid = tbl_entry->guid;



	} else if (et == EFI_TYPE_32) {

		efi_config_table_32_t *tbl_entry = (efi_config_table_32_t *)cfg_tbl + idx;



		*vendor_tbl_pa = tbl_entry->table;

		*vendor_tbl_guid = tbl_entry->guid;

	} else {

		return -EINVAL;

	}



	return 0;

}



/**

 * efi_find_vendor_table - Given EFI config table, search it for the physical

 *                         address of the vendor table associated with GUID.

 *

 * @bp:                pointer to boot_params

 * @cfg_tbl_pa:        pointer to EFI configuration table

 * @cfg_tbl_len:       number of entries in EFI configuration table

 * @guid:              GUID of vendor table

 *

 * Return: vendor table address on success. On error, return 0.

 */

unsigned long efi_find_vendor_table(struct boot_params *bp,

				    unsigned long cfg_tbl_pa,

				    unsigned int cfg_tbl_len,

				    efi_guid_t guid)

{

	enum efi_type et;

	unsigned int i;



	et = efi_get_type(bp);

	if (et == EFI_TYPE_NONE)

		return 0;



	for (i = 0; i < cfg_tbl_len; i++) {

		unsigned long vendor_tbl_pa;

		efi_guid_t vendor_tbl_guid;

		int ret;



		ret = get_vendor_table((void *)cfg_tbl_pa, i,

				       &vendor_tbl_pa,

				       &vendor_tbl_guid, et);

		if (ret)

			return 0;



		if (!efi_guidcmp(guid, vendor_tbl_guid))

			return vendor_tbl_pa;

	}



	return 0;

}

arch/x86/boot/compressed/misc.h

+13 −0
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include <linux/screen_info.h>

#include <linux/elf.h>

#include <linux/io.h>

#include <linux/efi.h>

#include <asm/page.h>

#include <asm/boot.h>

#include <asm/bootparam.h>
@@ -188,6 +189,10 @@ enum efi_type efi_get_type(struct boot_params *bp); 
unsigned long efi_get_system_table(struct boot_params *bp);

int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa,

		       unsigned int *cfg_tbl_len);

unsigned long efi_find_vendor_table(struct boot_params *bp,

				    unsigned long cfg_tbl_pa,

				    unsigned int cfg_tbl_len,

				    efi_guid_t guid);

#else

static inline enum efi_type efi_get_type(struct boot_params *bp)

{
@@ -205,6 +210,14 @@ static inline int efi_get_conf_table(struct boot_params *bp, 
{

	return -ENOENT;

}



static inline unsigned long efi_find_vendor_table(struct boot_params *bp,

						  unsigned long cfg_tbl_pa,

						  unsigned int cfg_tbl_len,

						  efi_guid_t guid)

{

	return 0;

}

#endif /* CONFIG_EFI */



#endif /* BOOT_COMPRESSED_MISC_H */