summaryrefslogtreecommitdiff
path: root/drivers/firmware/efi/libstub/efistub.h
diff options
context:
space:
mode:
authorArd Biesheuvel <ardb@kernel.org>2022-11-10 12:36:20 +0300
committerArd Biesheuvel <ardb@kernel.org>2022-11-11 01:14:14 +0300
commit550b33cfd445296868a478e8413ffb2e963eed32 (patch)
tree20293f6a8aa8916a87ef2a433a1a7fc4c3044556 /drivers/firmware/efi/libstub/efistub.h
parent23715a26c8d812912a70c6ac1ce67af649b95914 (diff)
downloadlinux-550b33cfd445296868a478e8413ffb2e963eed32.tar.xz
arm64: efi: Force the use of SetVirtualAddressMap() on Altra machines
Ampere Altra machines are reported to misbehave when the SetTime() EFI runtime service is called after ExitBootServices() but before calling SetVirtualAddressMap(). Given that the latter is horrid, pointless and explicitly documented as optional by the EFI spec, we no longer invoke it at boot if the configured size of the VA space guarantees that the EFI runtime memory regions can remain mapped 1:1 like they are at boot time. On Ampere Altra machines, this results in SetTime() calls issued by the rtc-efi driver triggering synchronous exceptions during boot. We can now recover from those without bringing down the system entirely, due to commit 23715a26c8d81291 ("arm64: efi: Recover from synchronous exceptions occurring in firmware"). However, it would be better to avoid the issue entirely, given that the firmware appears to remain in a funny state after this. So attempt to identify these machines based on the 'family' field in the type #1 SMBIOS record, and call SetVirtualAddressMap() unconditionally in that case. Tested-by: Alexandru Elisei <alexandru.elisei@gmail.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers/firmware/efi/libstub/efistub.h')
-rw-r--r--drivers/firmware/efi/libstub/efistub.h28
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/efistub.h b/drivers/firmware/efi/libstub/efistub.h
index a30fb5d8ef05..eb03d5a9aac8 100644
--- a/drivers/firmware/efi/libstub/efistub.h
+++ b/drivers/firmware/efi/libstub/efistub.h
@@ -975,4 +975,32 @@ efi_enable_reset_attack_mitigation(void) { }
void efi_retrieve_tpm2_eventlog(void);
+struct efi_smbios_record {
+ u8 type;
+ u8 length;
+ u16 handle;
+};
+
+struct efi_smbios_type1_record {
+ struct efi_smbios_record header;
+
+ u8 manufacturer;
+ u8 product_name;
+ u8 version;
+ u8 serial_number;
+ efi_guid_t uuid;
+ u8 wakeup_type;
+ u8 sku_number;
+ u8 family;
+};
+
+#define efi_get_smbios_string(__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); \
+})
+
+const u8 *__efi_get_smbios_string(u8 type, int offset, int recsize);
+
#endif