From 824f37783189a48db914488fb41eba36ec57ebb7 Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Thu, 24 Feb 2022 10:56:08 -0600 Subject: 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: Michael Roth Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-29-brijesh.singh@amd.com --- arch/x86/boot/compressed/acpi.c | 59 ----------------------------------------- arch/x86/boot/compressed/efi.c | 46 +++++++++++++++++++++++++++++++- 2 files changed, 45 insertions(+), 60 deletions(-) (limited to 'arch/x86/boot') diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index b0c1dffc5510..64b172dabd5c 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -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(); diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c index 4d363dfc2b33..09fa3b5d70b8 100644 --- a/arch/x86/boot/compressed/efi.c +++ b/arch/x86/boot/compressed/efi.c @@ -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; -- cgit v1.2.3