diff options
Diffstat (limited to 'arch/x86/xen/efi.c')
| -rw-r--r-- | arch/x86/xen/efi.c | 168 |
1 files changed, 168 insertions, 0 deletions
diff --git a/arch/x86/xen/efi.c b/arch/x86/xen/efi.c new file mode 100644 index 000000000..205a9bc98 --- /dev/null +++ b/arch/x86/xen/efi.c @@ -0,0 +1,168 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2014 Oracle Co., Daniel Kiper + */ + +#include <linux/bitops.h> +#include <linux/efi.h> +#include <linux/init.h> +#include <linux/string.h> + +#include <xen/xen.h> +#include <xen/xen-ops.h> +#include <xen/interface/platform.h> + +#include <asm/page.h> +#include <asm/setup.h> +#include <asm/xen/hypercall.h> + +static efi_char16_t vendor[100] __initdata; + +static efi_system_table_t efi_systab_xen __initdata = { + .hdr = { + .signature = EFI_SYSTEM_TABLE_SIGNATURE, + .revision = 0, /* Initialized later. */ + .headersize = 0, /* Ignored by Linux Kernel. */ + .crc32 = 0, /* Ignored by Linux Kernel. */ + .reserved = 0 + }, + .fw_vendor = EFI_INVALID_TABLE_ADDR, /* Initialized later. */ + .fw_revision = 0, /* Initialized later. */ + .con_in_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ + .con_in = NULL, /* Not used under Xen. */ + .con_out_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ + .con_out = NULL, /* Not used under Xen. */ + .stderr_handle = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ + .stderr = EFI_INVALID_TABLE_ADDR, /* Not used under Xen. */ + .runtime = (efi_runtime_services_t *)EFI_INVALID_TABLE_ADDR, + /* Not used under Xen. */ + .boottime = (efi_boot_services_t *)EFI_INVALID_TABLE_ADDR, + /* Not used under Xen. */ + .nr_tables = 0, /* Initialized later. */ + .tables = EFI_INVALID_TABLE_ADDR /* Initialized later. */ +}; + +static efi_system_table_t __init *xen_efi_probe(void) +{ + struct xen_platform_op op = { + .cmd = XENPF_firmware_info, + .u.firmware_info = { + .type = XEN_FW_EFI_INFO, + .index = XEN_FW_EFI_CONFIG_TABLE + } + }; + union xenpf_efi_info *info = &op.u.firmware_info.u.efi_info; + + if (!xen_initial_domain() || HYPERVISOR_platform_op(&op) < 0) + return NULL; + + /* Here we know that Xen runs on EFI platform. */ + xen_efi_runtime_setup(); + + efi_systab_xen.tables = info->cfg.addr; + efi_systab_xen.nr_tables = info->cfg.nent; + + op.cmd = XENPF_firmware_info; + op.u.firmware_info.type = XEN_FW_EFI_INFO; + op.u.firmware_info.index = XEN_FW_EFI_VENDOR; + info->vendor.bufsz = sizeof(vendor); + set_xen_guest_handle(info->vendor.name, vendor); + + if (HYPERVISOR_platform_op(&op) == 0) { + efi_systab_xen.fw_vendor = __pa_symbol(vendor); + efi_systab_xen.fw_revision = info->vendor.revision; + } else + efi_systab_xen.fw_vendor = __pa_symbol(L"UNKNOWN"); + + op.cmd = XENPF_firmware_info; + op.u.firmware_info.type = XEN_FW_EFI_INFO; + op.u.firmware_info.index = XEN_FW_EFI_VERSION; + + if (HYPERVISOR_platform_op(&op) == 0) + efi_systab_xen.hdr.revision = info->version; + + op.cmd = XENPF_firmware_info; + op.u.firmware_info.type = XEN_FW_EFI_INFO; + op.u.firmware_info.index = XEN_FW_EFI_RT_VERSION; + + if (HYPERVISOR_platform_op(&op) == 0) + efi.runtime_version = info->version; + + return &efi_systab_xen; +} + +/* + * Determine whether we're in secure boot mode. + * + * Please keep the logic in sync with + * drivers/firmware/efi/libstub/secureboot.c:efi_get_secureboot(). + */ +static enum efi_secureboot_mode xen_efi_get_secureboot(void) +{ + static efi_guid_t efi_variable_guid = EFI_GLOBAL_VARIABLE_GUID; + static efi_guid_t shim_guid = EFI_SHIM_LOCK_GUID; + efi_status_t status; + u8 moksbstate, secboot, setupmode; + unsigned long size; + + size = sizeof(secboot); + status = efi.get_variable(L"SecureBoot", &efi_variable_guid, + NULL, &size, &secboot); + + if (status == EFI_NOT_FOUND) + return efi_secureboot_mode_disabled; + + if (status != EFI_SUCCESS) + goto out_efi_err; + + size = sizeof(setupmode); + status = efi.get_variable(L"SetupMode", &efi_variable_guid, + NULL, &size, &setupmode); + + if (status != EFI_SUCCESS) + goto out_efi_err; + + if (secboot == 0 || setupmode == 1) + return efi_secureboot_mode_disabled; + + /* See if a user has put the shim into insecure mode. */ + size = sizeof(moksbstate); + status = efi.get_variable(L"MokSBStateRT", &shim_guid, + NULL, &size, &moksbstate); + + /* If it fails, we don't care why. Default to secure. */ + if (status != EFI_SUCCESS) + goto secure_boot_enabled; + + if (moksbstate == 1) + return efi_secureboot_mode_disabled; + + secure_boot_enabled: + pr_info("UEFI Secure Boot is enabled.\n"); + return efi_secureboot_mode_enabled; + + out_efi_err: + pr_err("Could not determine UEFI Secure Boot status.\n"); + return efi_secureboot_mode_unknown; +} + +void __init xen_efi_init(struct boot_params *boot_params) +{ + efi_system_table_t *efi_systab_xen; + + efi_systab_xen = xen_efi_probe(); + + if (efi_systab_xen == NULL) + return; + + strncpy((char *)&boot_params->efi_info.efi_loader_signature, "Xen", + sizeof(boot_params->efi_info.efi_loader_signature)); + boot_params->efi_info.efi_systab = (__u32)__pa(efi_systab_xen); + boot_params->efi_info.efi_systab_hi = (__u32)(__pa(efi_systab_xen) >> 32); + + boot_params->secure_boot = xen_efi_get_secureboot(); + + set_bit(EFI_BOOT, &efi.flags); + set_bit(EFI_PARAVIRT, &efi.flags); + set_bit(EFI_64BIT, &efi.flags); +} |