logging: Add missing compiler barrier after k_is_user_context

Remove the k_is_user_context call from the Z_LOG_LEVEL_ALL_CHECK macro.
Add the Z_LOG_LEVEL_ALL_CHECK_BREAK macro, which safely checks whether
logging is performed in user context before checking the dynamic log level
that requires access to kernel structure.

Signed-off-by: Adrian Warecki <adrian.warecki@intel.com>

Author: softwarecki

include/zephyr/logging/log_core.h

@@ -182,7 +182,7 @@ extern "C" {
  * @retval false Drop that message.
  */
 #define Z_LOG_DYNAMIC_LEVEL_CHECK(_level, _source)                                                 \
-	(!IS_ENABLED(CONFIG_LOG_RUNTIME_FILTERING) || k_is_user_context() ||                       \
+	(!IS_ENABLED(CONFIG_LOG_RUNTIME_FILTERING) ||                                              \
 	 ((_level) <= Z_LOG_RUNTIME_FILTER(((struct log_source_dynamic_data *)_source)->filters)))
 
 /** @brief Check if message shall be created.
@@ -199,7 +199,30 @@ extern "C" {
 #define Z_LOG_LEVEL_ALL_CHECK(_level, _inst, _source)                                              \
 	(Z_LOG_CONST_LEVEL_CHECK(_level) &&                                                        \
 	 Z_LOG_STATIC_INST_LEVEL_CHECK(_level, _inst, _source) &&                                  \
-	 Z_LOG_DYNAMIC_LEVEL_CHECK(_level, _source))
+	 COND_CODE_0(IS_ENABLED(CONFIG_USERSPACE),                                                 \
+		     (Z_LOG_DYNAMIC_LEVEL_CHECK(_level, _source)),                                 \
+		     (true))                                                                       \
+	)
+
+/** @brief Check if the message shall be created, otherwise break.
+ *
+ * Aggregate all checks into a single one. Calls break to skip message creation. Userspace safe.
+ *
+ * @param _level Log level.
+ * @param _inst 1 is source is the instance of a module.
+ * @param _source Data associated with the source.
+ */
+#define Z_LOG_LEVEL_ALL_CHECK_BREAK(_level, _inst, _source)                                        \
+	if (!Z_LOG_LEVEL_ALL_CHECK((_level), (_inst), (_source))) {                                \
+		break;                                                                             \
+	}                                                                                          \
+	IF_ENABLED(CONFIG_USERSPACE, (                                                             \
+	if (!k_is_user_context()) {                                                                \
+		compiler_barrier();                                                                \
+		if (!Z_LOG_DYNAMIC_LEVEL_CHECK((_level), (_source))) {                             \
+			break;                                                                     \
+		}                                                                                  \
+	}))
 
 /** @brief Get current module data that is used for source id retrieving.
  *
@@ -291,9 +314,7 @@ static inline char z_log_minimal_level_to_char(int level)
 #define Z_LOG2(_level, _inst, _source, ...)                                                        \
 	TOOLCHAIN_DISABLE_CLANG_WARNING(TOOLCHAIN_WARNING_USED_BUT_MARKED_UNUSED)                  \
 	do {                                                                                       \
-		if (!Z_LOG_LEVEL_ALL_CHECK(_level, _inst, _source)) {                              \
-			break;                                                                     \
-		}                                                                                  \
+		Z_LOG_LEVEL_ALL_CHECK_BREAK(_level, _inst, _source)                                \
 		if (IS_ENABLED(CONFIG_LOG_MODE_MINIMAL)) {                                         \
 			Z_LOG_TO_PRINTK(_level, __VA_ARGS__);                                      \
 			break;                                                                     \
@@ -346,9 +367,7 @@ static inline char z_log_minimal_level_to_char(int level)
 #define Z_LOG_HEXDUMP2(_level, _inst, _source, _data, _len, ...)                                   \
 	TOOLCHAIN_DISABLE_CLANG_WARNING(TOOLCHAIN_WARNING_USED_BUT_MARKED_UNUSED)                  \
 	do {                                                                                       \
-		if (!Z_LOG_LEVEL_ALL_CHECK(_level, _inst, _source)) {                              \
-			break;                                                                     \
-		}                                                                                  \
+		Z_LOG_LEVEL_ALL_CHECK_BREAK(_level, _inst, _source)                                \
 		const char *_str = GET_ARG_N(1, __VA_ARGS__);                                      \
 		if (IS_ENABLED(CONFIG_LOG_MODE_MINIMAL)) {                                         \
 			Z_LOG_TO_PRINTK(_level, "%s", _str);                                       \

subsys/logging/frontends/stmesp/zephyr_custom_log.h

@@ -40,9 +40,7 @@ extern "C" {
  */
 #define Z_LOG_STMESP_0(_level, _source, ...)                                                       \
 	do {                                                                                       \
-		if (!Z_LOG_LEVEL_ALL_CHECK(_level, __log_current_const_data, _source)) {           \
-			break;                                                                     \
-		}                                                                                  \
+		Z_LOG_LEVEL_ALL_CHECK_BREAK(_level, __log_current_const_data, _source)             \
 		LOG_FRONTEND_STMESP_LOG0(_source, STRINGIFY(_level) __VA_ARGS__);                  \
 	} while (0)
 
@@ -72,9 +70,7 @@ extern "C" {
 				(Z_LOG(_level, __VA_ARGS__)));                                     \
 			break;                                                                     \
 		}                                                                                  \
-		if (!Z_LOG_LEVEL_ALL_CHECK(_level, __log_current_const_data, _source)) {           \
-			break;                                                                     \
-		}                                                                                  \
+		Z_LOG_LEVEL_ALL_CHECK_BREAK(_level, __log_current_const_data, _source)             \
 		LOG_FRONTEND_STMESP_LOG1(_source, STRINGIFY(_level) __VA_ARGS__, dummy);           \
 	} while (0)