Commit 61c14ced authored by Michael Roth's avatar Michael Roth Committed by Borislav Petkov
Browse files

x86/compressed/acpi: Move EFI config 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: Remove superfluous zeroing of a stack variable. ]

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/20220307213356.2797205-27-brijesh.singh@amd.com
parent 58f3e6b7

arch/x86/boot/compressed/acpi.c

+8 −17
Original line number Diff line number Diff line
@@ -118,10 +118,13 @@ static acpi_physical_address kexec_get_rsdp_addr(void) { return 0; } 
static acpi_physical_address efi_get_rsdp_addr(void)

{

#ifdef CONFIG_EFI

	unsigned long systab_pa, config_tables;

	unsigned long cfg_tbl_pa = 0;

	unsigned int cfg_tbl_len;

	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)
@@ -135,23 +138,11 @@ static acpi_physical_address efi_get_rsdp_addr(void) 
	if (!systab_pa)

		error("EFI support advertised, but unable to locate system table.");



	/* Handle EFI bitness properly */

	if (efi_64) {

		efi_system_table_64_t *stbl = (efi_system_table_64_t *)systab_pa;



		config_tables	= stbl->tables;

		nr_tables	= stbl->nr_tables;

	} else {

		efi_system_table_32_t *stbl = (efi_system_table_32_t *)systab_pa;



		config_tables	= stbl->tables;

		nr_tables	= stbl->nr_tables;

	}



	if (!config_tables)

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

	ret = efi_get_conf_table(boot_params, &cfg_tbl_pa, &cfg_tbl_len);

	if (ret || !cfg_tbl_pa)

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



	return __efi_get_rsdp_addr(config_tables, nr_tables, efi_64);

	return __efi_get_rsdp_addr(cfg_tbl_pa, cfg_tbl_len, efi_64);

#else

	return 0;

#endif

arch/x86/boot/compressed/efi.c

+43 −0
Original line number Diff line number Diff line
@@ -77,3 +77,46 @@ unsigned long efi_get_system_table(struct boot_params *bp) 


	return sys_tbl_pa;

}



/**

 * efi_get_conf_table - Given a pointer to boot_params, locate and return the physical

 *                      address of EFI configuration table.

 *

 * @bp:                 pointer to boot_params

 * @cfg_tbl_pa:         location to store physical address of config table

 * @cfg_tbl_len:        location to store number of config table entries

 *

 * Return: 0 on success. On error, return params are left unchanged.

 */

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

		       unsigned int *cfg_tbl_len)

{

	unsigned long sys_tbl_pa;

	enum efi_type et;

	int ret;



	if (!cfg_tbl_pa || !cfg_tbl_len)

		return -EINVAL;



	sys_tbl_pa = efi_get_system_table(bp);

	if (!sys_tbl_pa)

		return -EINVAL;



	/* Handle EFI bitness properly */

	et = efi_get_type(bp);

	if (et == EFI_TYPE_64) {

		efi_system_table_64_t *stbl = (efi_system_table_64_t *)sys_tbl_pa;



		*cfg_tbl_pa = stbl->tables;

		*cfg_tbl_len = stbl->nr_tables;

	} else if (et == EFI_TYPE_32) {

		efi_system_table_32_t *stbl = (efi_system_table_32_t *)sys_tbl_pa;



		*cfg_tbl_pa = stbl->tables;

		*cfg_tbl_len = stbl->nr_tables;

	} else {

		return -EINVAL;

	}



	return 0;

}

arch/x86/boot/compressed/misc.h

+9 −0
Original line number Diff line number Diff line
@@ -186,6 +186,8 @@ enum efi_type { 
/* helpers for early EFI config table access */

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);

#else

static inline enum efi_type efi_get_type(struct boot_params *bp)

{
@@ -196,6 +198,13 @@ static inline unsigned long efi_get_system_table(struct boot_params *bp) 
{

	return 0;

}



static inline int efi_get_conf_table(struct boot_params *bp,

				     unsigned long *cfg_tbl_pa,

				     unsigned int *cfg_tbl_len)

{

	return -ENOENT;

}

#endif /* CONFIG_EFI */



#endif /* BOOT_COMPRESSED_MISC_H */