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@xxxxxxxxxxxxx>
Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
---
drivers/firmware/efi/libstub/arm64.c | 39 +++++++++++++++----
drivers/firmware/efi/libstub/efistub.h | 41 ++++++++++++++++++--
drivers/firmware/efi/libstub/smbios.c | 13 ++++++-
3 files changed, 80 insertions(+), 13 deletions(-)
diff --git a/drivers/firmware/efi/libstub/arm64.c b/drivers/firmware/efi/libstub/arm64.c
index 3997702663727e30..8aad8c49d43f18e0 100644
--- a/drivers/firmware/efi/libstub/arm64.c
+++ b/drivers/firmware/efi/libstub/arm64.c
@@ -16,20 +16,43 @@
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)
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index 6bd3bb86d9679a1c..330565b9263a6b01 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -1074,6 +1074,8 @@ 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;
@@ -1087,14 +1089,47 @@ 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);
void efi_remap_image(unsigned long image_base, unsigned alloc_size,
unsigned long code_size);
diff --git a/drivers/firmware/efi/libstub/smbios.c b/drivers/firmware/efi/libstub/smbios.c
index aadb422b9637dfc0..f9c159c28f4613f8 100644
--- 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++) {
--
2.39.2
