From 7c4146e8885512719a50b641e9277a1712e052ff Mon Sep 17 00:00:00 2001 From: Michael Roth Date: Wed, 9 Feb 2022 12:10:18 -0600 Subject: [PATCH] x86/compressed/acpi: Move EFI detection 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. First, carve out the functionality which determines the EFI environment type the machine is booting on. [ bp: Massage commit message. ] Signed-off-by: Michael Roth Signed-off-by: Brijesh Singh Signed-off-by: Borislav Petkov Link: https://lore.kernel.org/r/20220307213356.2797205-25-brijesh.singh@amd.com --- arch/x86/boot/compressed/Makefile | 1 + arch/x86/boot/compressed/acpi.c | 28 +++++++---------- arch/x86/boot/compressed/efi.c | 50 +++++++++++++++++++++++++++++++ arch/x86/boot/compressed/misc.h | 16 ++++++++++ 4 files changed, 77 insertions(+), 18 deletions(-) create mode 100644 arch/x86/boot/compressed/efi.c diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile index 6115274fe10f..e69c3d2e0628 100644 --- a/arch/x86/boot/compressed/Makefile +++ b/arch/x86/boot/compressed/Makefile @@ -103,6 +103,7 @@ endif vmlinux-objs-$(CONFIG_ACPI) += $(obj)/acpi.o vmlinux-objs-$(CONFIG_EFI_MIXED) += $(obj)/efi_thunk_$(BITS).o +vmlinux-objs-$(CONFIG_EFI) += $(obj)/efi.o efi-obj-$(CONFIG_EFI_STUB) = $(objtree)/drivers/firmware/efi/libstub/lib.a $(obj)/vmlinux: $(vmlinux-objs-y) $(efi-obj-y) FORCE diff --git a/arch/x86/boot/compressed/acpi.c b/arch/x86/boot/compressed/acpi.c index 8bcbcee54aa1..db6c561920f0 100644 --- a/arch/x86/boot/compressed/acpi.c +++ b/arch/x86/boot/compressed/acpi.c @@ -87,7 +87,7 @@ static acpi_physical_address kexec_get_rsdp_addr(void) efi_system_table_64_t *systab; struct efi_setup_data *esd; struct efi_info *ei; - char *sig; + enum efi_type et; esd = (struct efi_setup_data *)get_kexec_setup_data_addr(); if (!esd) @@ -98,10 +98,9 @@ static acpi_physical_address kexec_get_rsdp_addr(void) return 0; } - ei = &boot_params->efi_info; - sig = (char *)&ei->efi_loader_signature; - if (strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) { - debug_putstr("Wrong kexec EFI loader signature.\n"); + et = efi_get_type(boot_params); + if (et != EFI_TYPE_64) { + debug_putstr("Unexpected kexec EFI environment (expected 64-bit EFI).\n"); return 0; } @@ -122,29 +121,22 @@ static acpi_physical_address efi_get_rsdp_addr(void) unsigned long systab, config_tables; unsigned int nr_tables; struct efi_info *ei; + enum efi_type et; bool efi_64; - char *sig; - ei = &boot_params->efi_info; - sig = (char *)&ei->efi_loader_signature; - - if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) { + et = efi_get_type(boot_params); + if (et == EFI_TYPE_64) efi_64 = true; - } else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) { + else if (et == EFI_TYPE_32) efi_64 = false; - } else { - debug_putstr("Wrong EFI loader signature.\n"); + else return 0; - } /* Get systab from boot params. */ + ei = &boot_params->efi_info; #ifdef CONFIG_X86_64 systab = ei->efi_systab | ((__u64)ei->efi_systab_hi << 32); #else - if (ei->efi_systab_hi || ei->efi_memmap_hi) { - debug_putstr("Error getting RSDP address: EFI system table located above 4GB.\n"); - return 0; - } systab = ei->efi_systab; #endif if (!systab) diff --git a/arch/x86/boot/compressed/efi.c b/arch/x86/boot/compressed/efi.c new file mode 100644 index 000000000000..bad0ce3e2ef6 --- /dev/null +++ b/arch/x86/boot/compressed/efi.c @@ -0,0 +1,50 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Helpers for early access to EFI configuration table. + * + * Originally derived from arch/x86/boot/compressed/acpi.c + */ + +#include "misc.h" +#include +#include + +/** + * efi_get_type - Given a pointer to boot_params, determine the type of EFI environment. + * + * @bp: pointer to boot_params + * + * Return: EFI_TYPE_{32,64} for valid EFI environments, EFI_TYPE_NONE otherwise. + */ +enum efi_type efi_get_type(struct boot_params *bp) +{ + struct efi_info *ei; + enum efi_type et; + const char *sig; + + ei = &bp->efi_info; + sig = (char *)&ei->efi_loader_signature; + + if (!strncmp(sig, EFI64_LOADER_SIGNATURE, 4)) { + et = EFI_TYPE_64; + } else if (!strncmp(sig, EFI32_LOADER_SIGNATURE, 4)) { + et = EFI_TYPE_32; + } else { + debug_putstr("No EFI environment detected.\n"); + et = EFI_TYPE_NONE; + } + +#ifndef CONFIG_X86_64 + /* + * Existing callers like acpi.c treat this case as an indicator to + * fall-through to non-EFI, rather than an error, so maintain that + * functionality here as well. + */ + if (ei->efi_systab_hi || ei->efi_memmap_hi) { + debug_putstr("EFI system table is located above 4GB and cannot be accessed.\n"); + et = EFI_TYPE_NONE; + } +#endif + + return et; +} diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index 01cc13c12059..fede1afa39e9 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -176,4 +176,20 @@ void boot_stage2_vc(void); unsigned long sev_verify_cbit(unsigned long cr3); +enum efi_type { + EFI_TYPE_64, + EFI_TYPE_32, + EFI_TYPE_NONE, +}; + +#ifdef CONFIG_EFI +/* helpers for early EFI config table access */ +enum efi_type efi_get_type(struct boot_params *bp); +#else +static inline enum efi_type efi_get_type(struct boot_params *bp) +{ + return EFI_TYPE_NONE; +} +#endif /* CONFIG_EFI */ + #endif /* BOOT_COMPRESSED_MISC_H */