From: Ard Biesheuvel ardb@kernel.org
commit eb684408f3ea4856639675d6465f0024e498e4b1 upstream.
Instead of using the SMBIOS type 1 record 'family' field, which is often modified by OEMs, use the type 4 'processor ID' and 'processor version' fields, which are set to a small set of probe-able values on all known Ampere EFI systems in the field.
Fixes: 550b33cfd4452968 ("arm64: efi: Force the use of ...") Tested-by: Andrea Righi andrea.righi@canonical.com Signed-off-by: Ard Biesheuvel ardb@kernel.org Signed-off-by: Jeremi Piotrowski jpiotrowski@linux.microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/firmware/efi/libstub/arm64-stub.c | 39 ++++++++++++++++++++++------ drivers/firmware/efi/libstub/efistub.h | 41 +++++++++++++++++++++++++++--- drivers/firmware/efi/libstub/smbios.c | 13 ++++++++- 3 files changed, 80 insertions(+), 13 deletions(-)
--- a/drivers/firmware/efi/libstub/arm64-stub.c +++ b/drivers/firmware/efi/libstub/arm64-stub.c @@ -17,20 +17,43 @@
static bool system_needs_vamap(void) { - const u8 *type1_family = efi_get_smbios_string(1, family); + const struct efi_smbios_type4_record *record; + const u32 __aligned(1) *socid; + const u8 *version;
/* * Ampere eMAG, Altra, and Altra Max machines crash in SetTime() if - * SetVirtualAddressMap() has not been called prior. + * SetVirtualAddressMap() has not been called prior. Most Altra systems + * can be identified by the SMCCC soc ID, which is conveniently exposed + * via the type 4 SMBIOS records. Otherwise, test the processor version + * field. eMAG systems all appear to have the processor version field + * set to "eMAG". */ - if (!type1_family || ( - strcmp(type1_family, "eMAG") && - strcmp(type1_family, "Altra") && - strcmp(type1_family, "Altra Max"))) + record = (struct efi_smbios_type4_record *)efi_get_smbios_record(4); + if (!record) return false;
- efi_warn("Working around broken SetVirtualAddressMap()\n"); - return true; + socid = (u32 *)record->processor_id; + switch (*socid & 0xffff000f) { + static char const altra[] = "Ampere(TM) Altra(TM) Processor"; + static char const emag[] = "eMAG"; + + default: + version = efi_get_smbios_string(&record->header, 4, + processor_version); + if (!version || (strncmp(version, altra, sizeof(altra) - 1) && + strncmp(version, emag, sizeof(emag) - 1))) + break; + + fallthrough; + + case 0x0a160001: // Altra + case 0x0a160002: // Altra Max + efi_warn("Working around broken SetVirtualAddressMap()\n"); + return true; + } + + return false; }
efi_status_t check_platform_features(void) --- a/drivers/firmware/efi/libstub/efistub.h +++ b/drivers/firmware/efi/libstub/efistub.h @@ -983,6 +983,8 @@ struct efi_smbios_record { u16 handle; };
+const struct efi_smbios_record *efi_get_smbios_record(u8 type); + struct efi_smbios_type1_record { struct efi_smbios_record header;
@@ -996,13 +998,46 @@ struct efi_smbios_type1_record { u8 family; };
-#define efi_get_smbios_string(__type, __name) ({ \ +struct efi_smbios_type4_record { + struct efi_smbios_record header; + + u8 socket; + u8 processor_type; + u8 processor_family; + u8 processor_manufacturer; + u8 processor_id[8]; + u8 processor_version; + u8 voltage; + u16 external_clock; + u16 max_speed; + u16 current_speed; + u8 status; + u8 processor_upgrade; + u16 l1_cache_handle; + u16 l2_cache_handle; + u16 l3_cache_handle; + u8 serial_number; + u8 asset_tag; + u8 part_number; + u8 core_count; + u8 enabled_core_count; + u8 thread_count; + u16 processor_characteristics; + u16 processor_family2; + u16 core_count2; + u16 enabled_core_count2; + u16 thread_count2; + u16 thread_enabled; +}; + +#define efi_get_smbios_string(__record, __type, __name) ({ \ int size = sizeof(struct efi_smbios_type ## __type ## _record); \ int off = offsetof(struct efi_smbios_type ## __type ## _record, \ __name); \ - __efi_get_smbios_string(__type, off, size); \ + __efi_get_smbios_string((__record), __type, off, size); \ })
-const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize); +const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record, + u8 type, int offset, int recsize);
#endif --- a/drivers/firmware/efi/libstub/smbios.c +++ b/drivers/firmware/efi/libstub/smbios.c @@ -22,19 +22,28 @@ struct efi_smbios_protocol { u8 minor_version; };
-const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize) +const struct efi_smbios_record *efi_get_smbios_record(u8 type) { struct efi_smbios_record *record; efi_smbios_protocol_t *smbios; efi_status_t status; u16 handle = 0xfffe; - const u8 *strtable;
status = efi_bs_call(locate_protocol, &EFI_SMBIOS_PROTOCOL_GUID, NULL, (void **)&smbios) ?: efi_call_proto(smbios, get_next, &handle, &type, &record, NULL); if (status != EFI_SUCCESS) return NULL; + return record; +} + +const u8 *__efi_get_smbios_string(const struct efi_smbios_record *record, + u8 type, int offset, int recsize) +{ + const u8 *strtable; + + if (!record) + return NULL;
strtable = (u8 *)record + record->length; for (int i = 1; i < ((u8 *)record)[offset]; i++) {