From 89bb926a041b03c3926bf21266cbdf735d9aee66 Mon Sep 17 00:00:00 2001
From: Michael Brown
Date: Wed, 13 Mar 2024 15:16:47 +0000
Subject: [efi] Provide a multiprocessor API for EFI

Provide an implementation of the iPXE multiprocessor API for EFI,
based on using EFI_MP_SERVICES to start up a wrapper function on all
application processors.

Note that the processor numbers used by EFI_MP_SERVICES are opaque
integers that bear no relation to the underlying CPU identity
(e.g. the APIC ID), and so we must rely on our own (architecture-
specific) implementation to determine the relevant CPU identifiers.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
---
 src/interface/efi/efi_mp.c | 112 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 src/interface/efi/efi_mp.c

(limited to 'src/interface/efi/efi_mp.c')

diff --git a/src/interface/efi/efi_mp.c b/src/interface/efi/efi_mp.c
new file mode 100644
index 00000000..fdbbc9ae
--- /dev/null
+++ b/src/interface/efi/efi_mp.c
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2024 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ *
+ * You can also choose to distribute this program under the terms of
+ * the Unmodified Binary Distribution Licence (as given in the file
+ * COPYING.UBDL), provided that you have satisfied its requirements.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
+
+/** @file
+ *
+ * EFI multiprocessor API implementation
+ *
+ */
+
+#include <string.h>
+#include <errno.h>
+#include <ipxe/mp.h>
+#include <ipxe/efi/efi.h>
+#include <ipxe/efi/Protocol/MpService.h>
+
+/** EFI multiprocessor function call data */
+struct efi_mp_func_data {
+	/** Multiprocessor function */
+	mp_addr_t func;
+	/** Opaque data pointer */
+	mp_addr_t opaque;
+};
+
+/** Multiprocessor services protocol */
+static EFI_MP_SERVICES_PROTOCOL *efimp;
+EFI_REQUEST_PROTOCOL ( EFI_MP_SERVICES_PROTOCOL, &efimp );
+
+/**
+ * Call multiprocessor function on current CPU
+ *
+ * @v buffer		Multiprocessor function call data
+ */
+static EFIAPI VOID efi_mp_call ( VOID *buffer ) {
+	struct efi_mp_func_data *data = buffer;
+
+	/* Call multiprocessor function */
+	mp_call ( data->func, data->opaque );
+}
+
+/**
+ * Execute a multiprocessor function on the boot processor
+ *
+ * @v func		Multiprocessor function
+ * @v opaque		Opaque data pointer
+ */
+static void efi_mp_exec_boot ( mp_func_t func, void *opaque ) {
+	struct efi_mp_func_data data;
+
+	/* Construct call data */
+	data.func = mp_address ( func );
+	data.opaque = mp_address ( opaque );
+
+	/* Call multiprocesor function */
+	efi_mp_call ( &data );
+}
+
+/**
+ * Start a multiprocessor function on all application processors
+ *
+ * @v func		Multiprocessor function
+ * @v opaque		Opaque data pointer
+ */
+static void efi_mp_start_all ( mp_func_t func, void *opaque ) {
+	struct efi_mp_func_data data;
+	EFI_STATUS efirc;
+	int rc;
+
+	/* Do nothing if MP services is not present */
+	if ( ! efimp ) {
+		DBGC ( func, "EFIMP has no multiprocessor services\n" );
+		return;
+	}
+
+	/* Construct call data */
+	data.func = mp_address ( func );
+	data.opaque = mp_address ( opaque );
+
+	/* Start up all application processors */
+	if ( ( efirc = efimp->StartupAllAPs ( efimp, efi_mp_call, FALSE, NULL,
+					      0, &data, NULL ) ) != 0 ) {
+		rc = -EEFI ( efirc );
+		DBGC ( func, "EFIMP could not start APs: %s\n",
+		       strerror ( rc ) );
+		return;
+	}
+}
+
+PROVIDE_MPAPI_INLINE ( efi, mp_address );
+PROVIDE_MPAPI ( efi, mp_exec_boot, efi_mp_exec_boot );
+PROVIDE_MPAPI ( efi, mp_start_all, efi_mp_start_all );
-- 
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