Commit 824f3778 authored by Michael Roth's avatar Michael Roth Committed by Borislav Petkov
Browse files

x86/compressed/acpi: Move EFI kexec handling into common code 



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.

In this instance, the current acpi.c kexec handling is mainly used to
get the alternative EFI config table address provided by kexec via a
setup_data entry of type SETUP_EFI. If not present, the code then falls
back to normal EFI config table address provided by EFI system table.
This would need to be done by all call-sites attempting to access the
EFI config table, so just have efi_get_conf_table() handle that
automatically.

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/20220307213356.2797205-29-brijesh.singh@amd.com
parent dee602dd

arch/x86/boot/compressed/acpi.c

+0 −59
Original line number Diff line number Diff line
@@ -47,57 +47,6 @@ __efi_get_rsdp_addr(unsigned long cfg_tbl_pa, unsigned int cfg_tbl_len) 
	return 0;

}



/* 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;

	enum efi_type et;



	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;

	}



	et = efi_get_type(boot_params);

	if (et != EFI_TYPE_64) {

		debug_putstr("Unexpected kexec EFI environment (expected 64-bit EFI).\n");

		return 0;

	}



	/* Get systab from boot params. */

	systab = (efi_system_table_64_t *)efi_get_system_table(boot_params);

	if (!systab)

		error("EFI system table not found in kexec boot_params.");



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

}

#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
@@ -210,14 +159,6 @@ acpi_physical_address get_rsdp_addr(void) 


	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/efi.c

+45 −1
Original line number Diff line number Diff line
@@ -78,6 +78,46 @@ unsigned long efi_get_system_table(struct boot_params *bp) 
	return sys_tbl_pa;

}



/*

 * EFI config table address changes to virtual address after boot, which may

 * not be accessible for the kexec'd kernel. To address this, kexec provides

 * the initial physical address via a struct setup_data entry, which is

 * checked for here, along with some sanity checks.

 */

static struct efi_setup_data *get_kexec_setup_data(struct boot_params *bp,

						   enum efi_type et)

{

#ifdef CONFIG_X86_64

	struct efi_setup_data *esd = NULL;

	struct setup_data *data;

	u64 pa_data;



	pa_data = bp->hdr.setup_data;

	while (pa_data) {

		data = (struct setup_data *)pa_data;

		if (data->type == SETUP_EFI) {

			esd = (struct efi_setup_data *)(pa_data + sizeof(struct setup_data));

			break;

		}



		pa_data = data->next;

	}



	/*

	 * Original ACPI code falls back to attempting normal EFI boot in these

	 * cases, so maintain existing behavior by indicating non-kexec

	 * environment to the caller, but print them for debugging.

	 */

	if (esd && !esd->tables) {

		debug_putstr("kexec EFI environment missing valid configuration table.\n");

		return NULL;

	}



	return esd;

#endif

	return NULL;

}



/**

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

 *                      address of EFI configuration table.
@@ -106,8 +146,12 @@ int efi_get_conf_table(struct boot_params *bp, unsigned long *cfg_tbl_pa, 
	et = efi_get_type(bp);

	if (et == EFI_TYPE_64) {

		efi_system_table_64_t *stbl = (efi_system_table_64_t *)sys_tbl_pa;

		struct efi_setup_data *esd;



		*cfg_tbl_pa = stbl->tables;

		/* kexec provides an alternative EFI conf table, check for it. */

		esd = get_kexec_setup_data(bp, et);



		*cfg_tbl_pa = esd ? esd->tables : 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;