efi_loader: Enable RISCV_EFI_BOOT_PROTOCOL support
This adds support for new RISCV_EFI_BOOT_PROTOCOL to
communicate the boot hart ID to bootloader/kernel on RISC-V
UEFI platforms.
The specification of the protocol is hosted at:
https://github.com/riscv-non-isa/riscv-uefi
Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index 24f9a2b..e5e35fe 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -369,4 +369,14 @@
help
Enabling this option creates the ESRT UEFI system table.
+config EFI_RISCV_BOOT_PROTOCOL
+ bool "RISCV_EFI_BOOT_PROTOCOL support"
+ default y
+ depends on RISCV
+ help
+ The EFI_RISCV_BOOT_PROTOCOL is used to transfer the boot hart ID
+ to the next boot stage. It should be enabled as it is meant to
+ replace the transfer via the device-tree. The latter is not
+ possible on systems using ACPI.
+
endif
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index fd344ce..b2c664d 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -62,6 +62,7 @@
obj-$(CONFIG_GENERATE_SMBIOS_TABLE) += efi_smbios.o
obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_rng.o
obj-$(CONFIG_EFI_TCG2_PROTOCOL) += efi_tcg2.o
+obj-$(CONFIG_EFI_RISCV_BOOT_PROTOCOL) += efi_riscv.o
obj-$(CONFIG_EFI_LOAD_FILE2_INITRD) += efi_load_initrd.o
obj-$(CONFIG_EFI_SIGNATURE_SUPPORT) += efi_signature.o
diff --git a/lib/efi_loader/efi_riscv.c b/lib/efi_loader/efi_riscv.c
new file mode 100644
index 0000000..bccfefd
--- /dev/null
+++ b/lib/efi_loader/efi_riscv.c
@@ -0,0 +1,60 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Defines APIs that allow an OS to interact with UEFI firmware to query
+ * information about the boot hart ID.
+ *
+ * Copyright (c) 2022, Ventana Micro Systems Inc
+ */
+
+#define LOG_CATEGORY LOGC_EFI
+#include <common.h>
+#include <efi_loader.h>
+#include <efi_variable.h>
+#include <log.h>
+#include <asm/global_data.h>
+#include <efi_riscv.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+static const efi_guid_t efi_guid_riscv_boot_protocol = RISCV_EFI_BOOT_PROTOCOL_GUID;
+
+/**
+ * efi_riscv_get_boot_hartid() - return boot hart ID
+ * @this: RISCV_EFI_BOOT_PROTOCOL instance
+ * @boot_hartid: caller allocated memory to return boot hart id
+ * Return: status code
+ */
+static efi_status_t EFIAPI
+efi_riscv_get_boot_hartid(struct riscv_efi_boot_protocol *this,
+ efi_uintn_t *boot_hartid)
+{
+ EFI_ENTRY("%p, %p", this, boot_hartid);
+
+ if (this != &riscv_efi_boot_prot || !boot_hartid)
+ return EFI_INVALID_PARAMETER;
+
+ *boot_hartid = gd->arch.boot_hart;
+
+ return EFI_EXIT(EFI_SUCCESS);
+}
+
+struct riscv_efi_boot_protocol riscv_efi_boot_prot = {
+ .revision = RISCV_EFI_BOOT_PROTOCOL_REVISION,
+ .get_boot_hartid = efi_riscv_get_boot_hartid
+};
+
+/**
+ * efi_riscv_register() - register RISCV_EFI_BOOT_PROTOCOL
+ *
+ * Return: status code
+ */
+efi_status_t efi_riscv_register(void)
+{
+ efi_status_t ret = EFI_SUCCESS;
+
+ ret = efi_add_protocol(efi_root, &efi_guid_riscv_boot_protocol,
+ (void *)&riscv_efi_boot_prot);
+ if (ret != EFI_SUCCESS)
+ log_err("Cannot install RISCV_EFI_BOOT_PROTOCOL\n");
+ return ret;
+}
diff --git a/lib/efi_loader/efi_setup.c b/lib/efi_loader/efi_setup.c
index 49172e3..380adc1 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -247,6 +247,12 @@
goto out;
}
+ if (IS_ENABLED(CONFIG_EFI_RISCV_BOOT_PROTOCOL)) {
+ ret = efi_riscv_register();
+ if (ret != EFI_SUCCESS)
+ goto out;
+ }
+
/* Secure boot */
ret = efi_init_secure_boot();
if (ret != EFI_SUCCESS)