LLEXT full ARM relocation support (adding executable)

samples/subsys/llext/fs_loader/CMakeLists.txt

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+# Copyright (c) 2024 Schneider Electric
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+
+project(fs_loader)
+
+target_sources(app PRIVATE src/main.c src/log_extension.c src/export.c)
+
+# declare extension
+zephyr_llext(hello_world)
+zephyr_llext_sources(hello_world.llext/hello_world.c)
+
+zephyr_llext(hello_world_pic PIC)
+zephyr_llext_sources(hello_world.llext/hello_world.c)
+
+set(FAT_IMG ${CMAKE_CURRENT_BINARY_DIR}/llext_vfat.img)
+
+# generate image
+add_custom_target(vfat.img ALL
+    COMMAND ${CMAKE_CURRENT_LIST_DIR}/makeimg.sh ${FAT_IMG} ${CMAKE_CURRENT_BINARY_DIR}/hello_world.llext ${CMAKE_CURRENT_BINARY_DIR}/hello_world_pic.llext
+    WORKING_DIRECTORY ${ZEPHYR_BASE}
+    SOURCES ${CMAKE_CURRENT_LIST_DIR}/makeimg.sh
+    DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/hello_world.llext ${CMAKE_CURRENT_BINARY_DIR}/hello_world_pic.llext
+)

samples/subsys/llext/fs_loader/Kconfig

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+#
+# Copyright (c) 2024 Schneider Electric
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+config APP_WIPE_STORAGE
+	bool "Option to clear the flash area before mounting"
+	help
+	  Use this to force an existing file system to be created.
+
+config CONFIG_LLEXT_PIC
+	bool "Build LL extension with PIC enabled"
+	help
+	  Use this to force building LL extension in Position Independant Code.
+
+source "Kconfig.zephyr"

samples/subsys/llext/fs_loader/README.rst

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+.. zephyr:code-sample:: llext-fs-loader
+   :name: Linkable loadable extensions filesystem module
+   :relevant-api: llext
+
+   Manage loadable extensions using fielsystem.
+
+Overview
+********
+
+This example provides filesystem access to the :ref:`llext` system and provides the
+ability to manage loadable code extensions in the filesystem.
+
+Requirements
+************
+
+A board with a supported llext architecture and filesystem.
+
+Building
+********
+
+.. zephyr-app-commands::
+   :zephyr-app: samples/subsys/llext/fs_loader
+   :board: nucleo_l496zg
+   :goals: build
+   :compact:
+
+Running
+*******
+
+Once the board has booted, you will be presented with a shell console.
+All the llext system related commands are available as sub-commands of llext
+which can be seen with llext help
+
+.. code-block:: console
+
+  uart:~$ llext help
+  llext - Loadable extension commands
+  Subcommands:
+    list          :List loaded extensions and their size in memory
+    load_hex      :Load an elf file encoded in hex directly from the shell input.
+                   Syntax:
+                   <ext_name> <ext_hex_string>
+	load_fs       :Load an elf file encoded in elf directly from a filesystem.
+                   Syntax:
+                   <ext_name> <filepath>
+    unload        :Unload an extension by name. Syntax:
+                   <ext_name>
+    list_symbols  :List extension symbols. Syntax:
+                   <ext_name>
+    call_fn       :Call extension function with prototype void fn(void). Syntax:
+                   <ext_name> <function_name>
+
+A hello world llext extension can be found in hello_world.llext folder.
+
+This is built in parallel of zephyr and must be copied in filesystem.
+
+
+
+.. code-block:: console
+
+  uart:~$ llext load_fs hello_world /NAND:/hello_world.llext
+
+This extension can then be seen in the list of loaded extensions (`list`), its symbols printed
+(`list_symbols`), and the hello_world function which the extension exports can be called and
+run (`call_fn`).
+
+.. code-block:: console
+
+  uart:~$ llext call_fn hello_world start
+  hello world from new thread
+  thread id is ....

samples/subsys/llext/fs_loader/VERSION

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+VERSION_MAJOR = 0
+VERSION_MINOR = 1
+PATCHLEVEL = 0
+VERSION_TWEAK = 0
+EXTRAVERSION = fs_llext

samples/subsys/llext/fs_loader/boards/nucleo_l496zg.overlay

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+/*
+ * Copyright (c) 2024 Schneider Electric
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&usbotg_fs {
+    pinctrl-0 = <&usb_otg_fs_dm_pa11 &usb_otg_fs_dp_pa12>;
+	pinctrl-names = "default";
+	status = "okay";
+};
+/* hsi48 must be enabled for usb */
+&clk_hsi48 {
+	status = "okay";
+};
+
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		code_partition: partition@0 {
+			label = "code";
+			reg = <0x0000000 DT_SIZE_K(1024-128)>;
+			read-only;
+		};
+
+		/*
+		 * The final 128 KiB is reserved for the application.
+		 * Storage partition will be used by FCB/LittleFS/NVS
+		 * if enabled.
+		 */
+		storage_partition: partition@E0000 {
+			label = "storage";
+			reg = <0x00E0000 DT_SIZE_K(128)>;
+		};
+	};
+};
+
+/ {
+	msc_disk0 {
+		status="okay";
+		compatible = "zephyr,flash-disk";
+		partition = <&storage_partition>;
+		disk-name = "NAND";
+		/* cache-size == page erase size */
+		cache-size = <2048>;
+	};
+};

samples/subsys/llext/fs_loader/boards/stm32f4_disco.overlay

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+/*
+ * Copyright (c) 2024 Schneider Electric
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+&flash0 {
+	partitions {
+		compatible = "fixed-partitions";
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		code_partition: partition@0 {
+			label = "code";
+			reg = <0x0000000 DT_SIZE_K(1024-128)>;
+			read-only;
+		};
+
+		/*
+		 * The final 128 KiB is reserved for the application.
+		 * Storage partition will be used by FCB/LittleFS/NVS
+		 * if enabled.
+		 */
+		storage_partition: partition@E0000 {
+			label = "storage";
+			reg = <0x00E0000 DT_SIZE_K(128)>;
+			read-only;
+		};
+	};
+};
+
+/ {
+	msc_disk0 {
+		status="okay";
+		compatible = "zephyr,flash-disk";
+		partition = <&storage_partition>;
+		disk-name = "NAND";
+		/* cache-size == page erase size */
+		cache-size = <2048>;
+	};
+};

samples/subsys/llext/fs_loader/hello_world.llext/hello_world.c

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+/**
+ * Copyright (c) 2024 Schneider Electric
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+#include <zephyr/kernel.h>
+#include <string.h>
+#include <zephyr/llext/symbol.h>
+
+
+#include <zephyr/logging/log.h>
+/* In all files comprising the module but one */
+LOG_MODULE_DECLARE(extension, LOG_LEVEL_INF);
+
+
+/* semaphore to end extension thread */
+struct k_sem sem_end_thread;
+
+
+static void extension_thread(void *p1, void *p2, void *p3)
+{
+	LOG_INF("llext thread: start");
+
+	while (true) {
+		int ret = k_sem_take(&sem_end_thread, K_MSEC(1000));
+		if (ret != 0) {
+			/* timeout */
+			k_tid_t thread_id = k_sched_current_thread_query();
+			printk("Hello World from extension thread %p\n", thread_id);
+		} else {
+			/* quit thread */
+			break;
+		}
+	}
+
+	LOG_INF("llext thread: end");
+}
+
+#define STACK_SIZE 2048
+#define PRIORITY   5
+
+K_THREAD_STACK_DEFINE(hello_world_stack, STACK_SIZE);
+struct k_thread new_thread;
+
+void start(void)
+{
+	LOG_INF("Starting extension...");
+
+	k_sem_init(&sem_end_thread, 0, 10);
+
+	k_tid_t tid = k_thread_create(&new_thread, hello_world_stack, STACK_SIZE,
+								  extension_thread, NULL, NULL, NULL, PRIORITY,
+								  K_ESSENTIAL, K_MSEC(0));
+#ifdef CONFIG_THREAD_NAME
+	strncpy(new_thread.name, "extension", CONFIG_THREAD_MAX_NAME_LEN - 1);
+	/* Ensure NULL termination, truncate if longer */
+	new_thread.name[CONFIG_THREAD_MAX_NAME_LEN - 1] = '\0';
+
+#endif
+
+	LOG_INF("Extension Started tid=%p", tid);
+}
+
+void stop(void)
+{
+	k_sem_give(&sem_end_thread);
+}
+
+LL_EXTENSION_SYMBOL(start);
+LL_EXTENSION_SYMBOL(stop);

samples/subsys/llext/fs_loader/makeimg.sh

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+#!/bin/sh
+
+#
+# Copyright (c) 2024 Schneider Electric.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+# Create a FAT12 disk image to flash in memory
+# This tool requires the following to be available on the host system:
+#
+# - dosfstools
+# - mtools
+set -e
+
+PROGNAME=$(basename "$0")
+OUTPUT=$1
+LOGICAL_SECTOR_SIZE=512
+DISK_SIZE_KB=128
+
+usage() {
+    printf "Usage:\n\t%s output.img input1 [input2] [...]" "$PROGNAME"
+}
+
+die() {
+     >&2 printf "%s ERROR: " "$PROGNAME"
+    # We want die() to be usable exactly like printf
+    # shellcheck disable=SC2059
+    >&2 printf "%s\n" "$@"
+    exit 1 
+}
+
+if [ $# -lt 2 ]; then
+    usage
+    die "Not enough arguments."
+fi
+
+shift
+INPUTS="$*"
+
+printf "Creating empty '%s' image..." "$(basename "$OUTPUT")"
+dd if=/dev/zero of="$OUTPUT" bs=1k count=${DISK_SIZE_KB} status=none || die "dd to $OUTPUT"
+printf "done\nCreating FAT partition image..."
+mkfs.fat -F12 -S"$LOGICAL_SECTOR_SIZE" "$OUTPUT" >/dev/null || die "mkfs.vfat failed"
+printf "done\nCopying input files..."
+mcopy -i "$OUTPUT" "$INPUTS" "::/" || die "mcopy $OUTPUT $INPUTS"
+printf "done\n"