logging: Assign module data to memory partition 'k_log_partition'

The logging module data is assigned to the memory partition
'k_log_partition' so that a user mode thread can access this data (see
k_mem_domain_add_thread()). The 'k_log_partition' is created when:
- CONFIG_USERSPACE=y
- CONFIG_LOG_ALWAYS_RUNTIME=y

The option CONFIG_NO_OPTIMIZATIONS=y forces the logging module to use
the runtime message creation CONFIG_LOG_ALWAYS_RUNTIME=y. This raises a
MPU violation when logging is used in a user mode thread since this
thread is not allowed to access the module data (e.g. __log_level,
__log_current_const_data).

Note that the user mode thread may also require access to the partition
'z_libc_partition'.

Signed-off-by: Christoph Winklhofer <[email protected]>

Author: cjwinklhofer

include/zephyr/logging/log.h

@@ -11,6 +11,10 @@
 #include <zephyr/logging/log_core.h>
 #include <zephyr/sys/iterable_sections.h>
 
+#if CONFIG_USERSPACE && CONFIG_LOG_ALWAYS_RUNTIME
+#include <zephyr/app_memory/app_memdomain.h>
+#endif
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -355,6 +359,16 @@ void z_log_vprintk(const char *fmt, va_list ap);
 		   (Z_LOG_EVAL(_LOG_LEVEL_RESOLVE(__VA_ARGS__), (1), (0))) \
 		  )), (0))
 
+/* Determine if the data of the log module shall be in the partition
+ * 'k_log_partition' to allow a user mode thread access to this data.
+ */
+#if CONFIG_USERSPACE && CONFIG_LOG_ALWAYS_RUNTIME
+extern struct k_mem_partition k_log_partition;
+#define Z_LOG_MODULE_PARTITION(_k_app_mem) _k_app_mem(k_log_partition)
+#else
+#define Z_LOG_MODULE_PARTITION(_k_app_mem)
+#endif
+
 /**
  * @brief Create module-specific state and register the module with Logger.
  *
@@ -427,19 +441,22 @@ void z_log_vprintk(const char *fmt, va_list ap);
 	extern struct log_source_dynamic_data				      \
 			LOG_ITEM_DYNAMIC_DATA(GET_ARG_N(1, __VA_ARGS__));     \
 									      \
+	Z_LOG_MODULE_PARTITION(K_APP_DMEM)				      \
 	static const struct log_source_const_data *			      \
 		__log_current_const_data __unused =			      \
 			Z_DO_LOG_MODULE_REGISTER(__VA_ARGS__) ?		      \
 			&Z_LOG_ITEM_CONST_DATA(GET_ARG_N(1, __VA_ARGS__)) :   \
 			NULL;						      \
 									      \
+	Z_LOG_MODULE_PARTITION(K_APP_DMEM)				      \
 	static struct log_source_dynamic_data *				      \
 		__log_current_dynamic_data __unused =			      \
 			(Z_DO_LOG_MODULE_REGISTER(__VA_ARGS__) &&	      \
 			IS_ENABLED(CONFIG_LOG_RUNTIME_FILTERING)) ?	      \
 			&LOG_ITEM_DYNAMIC_DATA(GET_ARG_N(1, __VA_ARGS__)) :   \
 			NULL;						      \
 									      \
+	Z_LOG_MODULE_PARTITION(K_APP_BMEM)				      \
 	static const uint32_t __log_level __unused =			      \
 					_LOG_LEVEL_RESOLVE(__VA_ARGS__)
 

subsys/logging/log_core.c

@@ -27,6 +27,11 @@
 #include <zephyr/posix/time.h>
 #endif
 
+#if CONFIG_USERSPACE && CONFIG_LOG_ALWAYS_RUNTIME
+#include <zephyr/app_memory/app_memdomain.h>
+K_APPMEM_PARTITION_DEFINE(k_log_partition);
+#endif
+
 LOG_MODULE_REGISTER(log);
 
 #ifndef CONFIG_LOG_PROCESS_THREAD_SLEEP_MS