[RFC PATCH V2 0/2] RISCV_EFI_BOOT_PROTOCOL support in U-boot

[RFC PATCH V2 0/2] RISCV_EFI_BOOT_PROTOCOL support in U-boot

[Sunil V L]

This patch series adds the support in u-boot for new RISCV_EFI_BOOT_PROTOCOL for RISC-V
UEFI platforms. This protocol is required to communicate the boot hart ID to the
bootloader/kernel which need to follow the EFI calling conventions.

The latest draft spec of this new protocol is available at
https://github.com/riscv-non-isa/riscv-uefi/releases/download/1.0-rc2/RISCV_UEFI_PROTOCOL-spec.pdf

This u-boot patches can be found in:
riscv_boot_protocol_rfc_v2 branch at https://github.com/vlsunil/u-boot.git

These patches are tested in qemu. To fully test the feature, we need
Linux changes which consume this protocol.
The linux patch can be found in:
riscv_boot_protocol_rfc_v2 branch at https://github.com/vlsunil/linux.git

Changes since RFC V1:
    - Used EFI_ENTRY/EXIT and removed need for static variable
    - Addressed other comments from Heinrich
    - Added unit test patch

Sunil V L (2):
  efi_loader: Enable RISCV_EFI_BOOT_PROTOCOL support
  efi_selftest: unit test for RISCV_EFI_BOOT_PROTOCOL

 include/efi_api.h                     |   4 +
 include/efi_loader.h                  |   2 +
 include/efi_riscv.h                   |  24 ++++++
 lib/efi_loader/Kconfig                |   8 ++
 lib/efi_loader/Makefile               |   1 +
 lib/efi_loader/efi_riscv.c            |  60 +++++++++++++
 lib/efi_loader/efi_setup.c            |   6 ++
 lib/efi_selftest/Makefile             |   1 +
 lib/efi_selftest/efi_selftest_riscv.c | 119 ++++++++++++++++++++++++++
 9 files changed, 225 insertions(+)
 create mode 100644 include/efi_riscv.h
 create mode 100644 lib/efi_loader/efi_riscv.c
 create mode 100644 lib/efi_selftest/efi_selftest_riscv.c

-- 
2.25.1

[RFC PATCH V2 1/2] efi_loader: Enable RISCV_EFI_BOOT_PROTOCOL support

[Sunil V L]

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>
---
 include/efi_api.h          |  4 +++
 include/efi_loader.h       |  2 ++
 include/efi_riscv.h        | 24 +++++++++++++++
 lib/efi_loader/Kconfig     |  8 +++++
 lib/efi_loader/Makefile    |  1 +
 lib/efi_loader/efi_riscv.c | 60 ++++++++++++++++++++++++++++++++++++++
 lib/efi_loader/efi_setup.c |  6 ++++
 7 files changed, 105 insertions(+)
 create mode 100644 include/efi_riscv.h
 create mode 100644 lib/efi_loader/efi_riscv.c

diff --git a/include/efi_api.h b/include/efi_api.h
index 8d5d835bd0..f123d0557c 100644
--- a/include/efi_api.h
+++ b/include/efi_api.h
@@ -438,6 +438,10 @@ struct efi_runtime_services {
 	EFI_GUID(0x607f766c, 0x7455, 0x42be, 0x93, \
 		 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
 
+#define RISCV_EFI_BOOT_PROTOCOL_GUID \
+	EFI_GUID(0xccd15fec, 0x6f73, 0x4eec, 0x83, \
+		 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)
+
 /**
  * struct efi_configuration_table - EFI Configuration Table
  *
diff --git a/include/efi_loader.h b/include/efi_loader.h
index 701efcd2b6..1fa75b40fe 100644
--- a/include/efi_loader.h
+++ b/include/efi_loader.h
@@ -527,6 +527,8 @@ efi_status_t efi_disk_register(void);
 efi_status_t efi_rng_register(void);
 /* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
 efi_status_t efi_tcg2_register(void);
+/* Called by efi_init_obj_list() to install RISCV_EFI_BOOT_PROTOCOL */
+efi_status_t efi_riscv_register(void);
 /* Called by efi_init_obj_list() to do initial measurement */
 efi_status_t efi_tcg2_do_initial_measurement(void);
 /* measure the pe-coff image, extend PCR and add Event Log */
diff --git a/include/efi_riscv.h b/include/efi_riscv.h
new file mode 100644
index 0000000000..4bd39c4366
--- /dev/null
+++ b/include/efi_riscv.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * RISCV_EFI_BOOT_PROTOCOL
+ *
+ * Copyright (c) 2022 Ventana Micro Systems Inc
+ */
+
+#include <efi_api.h>
+
+#define RISCV_EFI_BOOT_PROTOCOL_REVISION 0x00010000
+
+/**
+ * struct riscv_efi_boot_protocol - RISCV_EFI_BOOT_PROTOCOL
+ * @revision:		Version of the protocol implemented
+ * @get_boot_hartid:	Get the boot hart ID
+ */
+struct riscv_efi_boot_protocol {
+	u64 revision;
+
+	efi_status_t (EFIAPI * get_boot_hartid) (struct riscv_efi_boot_protocol *this,
+						 efi_uintn_t *boot_hartid);
+};
+
+extern struct riscv_efi_boot_protocol riscv_efi_boot_prot;
diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
index 24f9a2bb75..716436e1d3 100644
--- a/lib/efi_loader/Kconfig
+++ b/lib/efi_loader/Kconfig
@@ -369,4 +369,12 @@ config EFI_ESRT
 	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
+	  Provide a RISCV_EFI_BOOT_PROTOCOL implementation on RISC-V
+	  platforms.
+
 endif
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index fd344cea29..b2c664d108 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o
 obj-$(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 0000000000..bccfefd8fb
--- /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 49172e3579..380adc15c8 100644
--- a/lib/efi_loader/efi_setup.c
+++ b/lib/efi_loader/efi_setup.c
@@ -247,6 +247,12 @@ efi_status_t efi_init_obj_list(void)
 			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)
-- 
2.25.1

[RFC PATCH V2 2/2] efi_selftest: unit test for RISCV_EFI_BOOT_PROTOCOL

[Sunil V L]

Add a test for the RISCV_EFI_BOOT_PROTOCOL.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
---
 lib/efi_selftest/Makefile             |   1 +
 lib/efi_selftest/efi_selftest_riscv.c | 119 ++++++++++++++++++++++++++
 2 files changed, 120 insertions(+)
 create mode 100644 lib/efi_selftest/efi_selftest_riscv.c

diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
index 9ff6e1760c..0b05f8a591 100644
--- a/lib/efi_selftest/Makefile
+++ b/lib/efi_selftest/Makefile
@@ -64,6 +64,7 @@ obj-$(CONFIG_EFI_LOADER_HII) += efi_selftest_hii.o
 obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_selftest_rng.o
 obj-$(CONFIG_EFI_GET_TIME) += efi_selftest_rtc.o
 obj-$(CONFIG_EFI_TCG2_PROTOCOL) += efi_selftest_tcg2.o
+obj-$(CONFIG_EFI_RISCV_BOOT_PROTOCOL) += efi_selftest_riscv.o
 
 ifeq ($(CONFIG_GENERATE_ACPI_TABLE),)
 obj-y += efi_selftest_fdt.o
diff --git a/lib/efi_selftest/efi_selftest_riscv.c b/lib/efi_selftest/efi_selftest_riscv.c
new file mode 100644
index 0000000000..9d2182e61f
--- /dev/null
+++ b/lib/efi_selftest/efi_selftest_riscv.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * efi_selftest_riscv
+ *
+ * Copyright (c) 2022 Ventana Micro Systems Inc
+ *
+ * Test the RISCV_EFI_BOOT_PROTOCOL.
+ *
+ * The following services are tested:
+ * get_boot_hartid
+ */
+
+#include <efi_selftest.h>
+#include <efi_riscv.h>
+#include <linux/libfdt.h>
+
+static const struct efi_system_table *systemtab;
+static const struct efi_boot_services *boottime;
+static const char *fdt;
+static const efi_guid_t riscv_efi_boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
+static const efi_guid_t fdt_guid = EFI_FDT_GUID;
+
+/**
+ * efi_st_get_config_table() - get configuration table
+ *
+ * @guid:	GUID of the configuration table
+ * Return:	pointer to configuration table or NULL
+ */
+static void *efi_st_get_config_table(const efi_guid_t *guid)
+{
+	size_t i;
+
+	for (i = 0; i < systab.nr_tables; i++) {
+		if (!guidcmp(guid, &systemtab->tables[i].guid))
+			return systemtab->tables[i].table;
+	}
+	return NULL;
+}
+
+/*
+ * Setup unit test.
+ *
+ * @handle:	handle of the loaded image
+ * @systable:	system table
+ * @return:	EFI_ST_SUCCESS for success
+ */
+static int setup(const efi_handle_t img_handle,
+		 const struct efi_system_table *systable)
+{
+	systemtab = systable;
+	boottime = systable->boottime;
+
+	fdt = efi_st_get_config_table(&fdt_guid);
+
+	if (!fdt) {
+		efi_st_error("Missing device tree\n");
+		return EFI_ST_FAILURE;
+	}
+	return EFI_ST_SUCCESS;
+}
+
+/*
+ * Execute unit test.
+ *
+ * @return:	EFI_ST_SUCCESS for success
+ */
+static int execute(void)
+{
+	efi_status_t ret;
+	struct riscv_efi_boot_protocol *prot;
+	efi_uintn_t efi_hartid, fdt_hartid;
+	int chosen_node, len;
+	const fdt32_t *prop;
+
+	/* Get riscv boot protocol */
+	ret = boottime->locate_protocol(&riscv_efi_boot_protocol_guid, NULL,
+					(void **)&prot);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("RISC-V Boot Protocol not available\n");
+		return EFI_ST_FAILURE;
+	}
+
+	/* Get Boot Hart ID from EFI protocol */
+	ret = prot->get_boot_hartid(prot, &efi_hartid);
+	if (ret != EFI_SUCCESS) {
+		efi_st_error("Could not retrieve boot hart ID\n");
+		return EFI_ST_FAILURE;
+	}
+
+	/* Get Boot Hart ID from FDT */
+	chosen_node = fdt_path_offset(fdt, "/chosen");
+	if (chosen_node < 0) {
+		efi_st_error("/chosen node not found\n");
+		return EFI_ST_FAILURE;
+	}
+
+	prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
+	if (!prop || len != sizeof(u32)) {
+		efi_st_error("boot-hartid not found\n");
+		return EFI_ST_FAILURE;
+	}
+
+	fdt_hartid = fdt32_to_cpu(*prop);
+
+	/* Boot Hart ID should be same */
+	if (efi_hartid != fdt_hartid) {
+		efi_st_error("boot-hartid is not same in EFI and FDT\n");
+		return EFI_ST_FAILURE;
+	}
+
+	return EFI_ST_SUCCESS;
+}
+
+EFI_UNIT_TEST(riscv) = {
+	.name = "riscv",
+	.phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
+	.setup = setup,
+	.execute = execute,
+};
-- 
2.25.1

Re: [RFC PATCH V2 2/2] efi_selftest: unit test for RISCV_EFI_BOOT_PROTOCOL

[Heinrich Schuchardt]

On 1/28/22 16:18, Sunil V L wrote:
> Add a test for the RISCV_EFI_BOOT_PROTOCOL.
>
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> ---
>   lib/efi_selftest/Makefile             |   1 +
>   lib/efi_selftest/efi_selftest_riscv.c | 119 ++++++++++++++++++++++++++
>   2 files changed, 120 insertions(+)
>   create mode 100644 lib/efi_selftest/efi_selftest_riscv.c
>
> diff --git a/lib/efi_selftest/Makefile b/lib/efi_selftest/Makefile
> index 9ff6e1760c..0b05f8a591 100644
> --- a/lib/efi_selftest/Makefile
> +++ b/lib/efi_selftest/Makefile
> @@ -64,6 +64,7 @@ obj-$(CONFIG_EFI_LOADER_HII) += efi_selftest_hii.o
>   obj-$(CONFIG_EFI_RNG_PROTOCOL) += efi_selftest_rng.o
>   obj-$(CONFIG_EFI_GET_TIME) += efi_selftest_rtc.o
>   obj-$(CONFIG_EFI_TCG2_PROTOCOL) += efi_selftest_tcg2.o
> +obj-$(CONFIG_EFI_RISCV_BOOT_PROTOCOL) += efi_selftest_riscv.o
>
>   ifeq ($(CONFIG_GENERATE_ACPI_TABLE),)
>   obj-y += efi_selftest_fdt.o
> diff --git a/lib/efi_selftest/efi_selftest_riscv.c b/lib/efi_selftest/efi_selftest_riscv.c
> new file mode 100644
> index 0000000000..9d2182e61f
> --- /dev/null
> +++ b/lib/efi_selftest/efi_selftest_riscv.c
> @@ -0,0 +1,119 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * efi_selftest_riscv
> + *
> + * Copyright (c) 2022 Ventana Micro Systems Inc
> + *
> + * Test the RISCV_EFI_BOOT_PROTOCOL.
> + *
> + * The following services are tested:
> + * get_boot_hartid
> + */
> +
> +#include <efi_selftest.h>
> +#include <efi_riscv.h>
> +#include <linux/libfdt.h>
> +
> +static const struct efi_system_table *systemtab;
> +static const struct efi_boot_services *boottime;
> +static const char *fdt;
> +static const efi_guid_t riscv_efi_boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
> +static const efi_guid_t fdt_guid = EFI_FDT_GUID;
> +
> +/**
> + * efi_st_get_config_table() - get configuration table
> + *
> + * @guid:	GUID of the configuration table
> + * Return:	pointer to configuration table or NULL
> + */
> +static void *efi_st_get_config_table(const efi_guid_t *guid)
> +{
> +	size_t i;
> +
> +	for (i = 0; i < systab.nr_tables; i++) {
> +		if (!guidcmp(guid, &systemtab->tables[i].guid))
> +			return systemtab->tables[i].table;
> +	}
> +	return NULL;
> +}
> +
> +/*
> + * Setup unit test.
> + *
> + * @handle:	handle of the loaded image
> + * @systable:	system table
> + * @return:	EFI_ST_SUCCESS for success
> + */
> +static int setup(const efi_handle_t img_handle,
> +		 const struct efi_system_table *systable)
> +{
> +	systemtab = systable;
> +	boottime = systable->boottime;
> +
> +	fdt = efi_st_get_config_table(&fdt_guid);
> +
> +	if (!fdt) {
> +		efi_st_error("Missing device tree\n");
> +		return EFI_ST_FAILURE;
> +	}
> +	return EFI_ST_SUCCESS;
> +}
> +
> +/*
> + * Execute unit test.
> + *
> + * @return:	EFI_ST_SUCCESS for success
> + */
> +static int execute(void)
> +{
> +	efi_status_t ret;
> +	struct riscv_efi_boot_protocol *prot;
> +	efi_uintn_t efi_hartid, fdt_hartid;
> +	int chosen_node, len;
> +	const fdt32_t *prop;
> +
> +	/* Get riscv boot protocol */
> +	ret = boottime->locate_protocol(&riscv_efi_boot_protocol_guid, NULL,
> +					(void **)&prot);
> +	if (ret != EFI_SUCCESS) {
> +		efi_st_error("RISC-V Boot Protocol not available\n");
> +		return EFI_ST_FAILURE;
> +	}
> +
> +	/* Get Boot Hart ID from EFI protocol */
> +	ret = prot->get_boot_hartid(prot, &efi_hartid);
> +	if (ret != EFI_SUCCESS) {
> +		efi_st_error("Could not retrieve boot hart ID\n");
> +		return EFI_ST_FAILURE;
> +	}
> +
> +	/* Get Boot Hart ID from FDT */
> +	chosen_node = fdt_path_offset(fdt, "/chosen");
> +	if (chosen_node < 0) {
> +		efi_st_error("/chosen node not found\n");
> +		return EFI_ST_FAILURE;
> +	}
> +
> +	prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);

Thanks a lot for providing a test.

In the UEFI selftests we are not having access to gd. We should not call
into U-Boot except using the UEFI API. Otherwise any printf() (e.g.
debug output) in the called function will cause a crash.

I will add a patch to move get_property() of efi_selftest_fdt.c to an
exported function and tweak your patch accordingly.

> +	if (!prop || len != sizeof(u32)) {
> +		efi_st_error("boot-hartid not found\n");
> +		return EFI_ST_FAILURE;
> +	}
> +
> +	fdt_hartid = fdt32_to_cpu(*prop);

We should do the same for f2h() in efi_selftest_fdt.c.

Otherwise looks good to me.

Best regards

Heinrich

> +
> +	/* Boot Hart ID should be same */
> +	if (efi_hartid != fdt_hartid) {
> +		efi_st_error("boot-hartid is not same in EFI and FDT\n");
> +		return EFI_ST_FAILURE;
> +	}
> +
> +	return EFI_ST_SUCCESS;
> +}
> +
> +EFI_UNIT_TEST(riscv) = {
> +	.name = "riscv",
> +	.phase = EFI_EXECUTE_BEFORE_BOOTTIME_EXIT,
> +	.setup = setup,
> +	.execute = execute,
> +};

Re: [RFC PATCH V2 1/2] efi_loader: Enable RISCV_EFI_BOOT_PROTOCOL support

[Heinrich Schuchardt]

On 1/28/22 16:18, Sunil V L wrote:
> 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>
> ---
>   include/efi_api.h          |  4 +++
>   include/efi_loader.h       |  2 ++
>   include/efi_riscv.h        | 24 +++++++++++++++
>   lib/efi_loader/Kconfig     |  8 +++++
>   lib/efi_loader/Makefile    |  1 +
>   lib/efi_loader/efi_riscv.c | 60 ++++++++++++++++++++++++++++++++++++++
>   lib/efi_loader/efi_setup.c |  6 ++++
>   7 files changed, 105 insertions(+)
>   create mode 100644 include/efi_riscv.h
>   create mode 100644 lib/efi_loader/efi_riscv.c
> 
> diff --git a/include/efi_api.h b/include/efi_api.h
> index 8d5d835bd0..f123d0557c 100644
> --- a/include/efi_api.h
> +++ b/include/efi_api.h
> @@ -438,6 +438,10 @@ struct efi_runtime_services {
>   	EFI_GUID(0x607f766c, 0x7455, 0x42be, 0x93, \
>   		 0x0b, 0xe4, 0xd7, 0x6d, 0xb2, 0x72, 0x0f)
>   
> +#define RISCV_EFI_BOOT_PROTOCOL_GUID \
> +	EFI_GUID(0xccd15fec, 0x6f73, 0x4eec, 0x83, \
> +		 0x95, 0x3e, 0x69, 0xe4, 0xb9, 0x40, 0xbf)
> +
>   /**
>    * struct efi_configuration_table - EFI Configuration Table
>    *
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 701efcd2b6..1fa75b40fe 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -527,6 +527,8 @@ efi_status_t efi_disk_register(void);
>   efi_status_t efi_rng_register(void);
>   /* Called by efi_init_obj_list() to install EFI_TCG2_PROTOCOL */
>   efi_status_t efi_tcg2_register(void);
> +/* Called by efi_init_obj_list() to install RISCV_EFI_BOOT_PROTOCOL */
> +efi_status_t efi_riscv_register(void);
>   /* Called by efi_init_obj_list() to do initial measurement */
>   efi_status_t efi_tcg2_do_initial_measurement(void);
>   /* measure the pe-coff image, extend PCR and add Event Log */
> diff --git a/include/efi_riscv.h b/include/efi_riscv.h
> new file mode 100644
> index 0000000000..4bd39c4366
> --- /dev/null
> +++ b/include/efi_riscv.h
> @@ -0,0 +1,24 @@
> +/* SPDX-License-Identifier: GPL-2.0+ */
> +/*
> + * RISCV_EFI_BOOT_PROTOCOL
> + *
> + * Copyright (c) 2022 Ventana Micro Systems Inc
> + */
> +
> +#include <efi_api.h>
> +
> +#define RISCV_EFI_BOOT_PROTOCOL_REVISION 0x00010000
> +
> +/**
> + * struct riscv_efi_boot_protocol - RISCV_EFI_BOOT_PROTOCOL
> + * @revision:		Version of the protocol implemented
> + * @get_boot_hartid:	Get the boot hart ID
> + */
> +struct riscv_efi_boot_protocol {
> +	u64 revision;
> +
> +	efi_status_t (EFIAPI * get_boot_hartid) (struct riscv_efi_boot_protocol *this,
> +						 efi_uintn_t *boot_hartid);
> +};
> +
> +extern struct riscv_efi_boot_protocol riscv_efi_boot_prot;
> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
> index 24f9a2bb75..716436e1d3 100644
> --- a/lib/efi_loader/Kconfig
> +++ b/lib/efi_loader/Kconfig
> @@ -369,4 +369,12 @@ config EFI_ESRT
>   	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
> +	  Provide a RISCV_EFI_BOOT_PROTOCOL implementation on RISC-V
> +	  platforms.

I will add a sentence mentioning what the protocol is good for when merging.

Otherwise looks good to me.

Reviewed-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

> +
>   endif
> diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
> index fd344cea29..b2c664d108 100644
> --- a/lib/efi_loader/Makefile
> +++ b/lib/efi_loader/Makefile
> @@ -62,6 +62,7 @@ obj-$(CONFIG_GENERATE_ACPI_TABLE) += efi_acpi.o
>   obj-$(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 0000000000..bccfefd8fb
> --- /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 49172e3579..380adc15c8 100644
> --- a/lib/efi_loader/efi_setup.c
> +++ b/lib/efi_loader/efi_setup.c
> @@ -247,6 +247,12 @@ efi_status_t efi_init_obj_list(void)
>   			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)