Implement log framework
This patch gives users control over logging messages printed from the C
code using the LOG macros defined in debug.h Users now have the ability
to reduce the log_level at run time using the tf_log_set_max_level()
function. The default prefix string can be defined by platform by
overriding the `plat_log_get_prefix()` platform API which is also
introduced in this patch.
The new log framework results in saving of some RO data. For example,
when BL1 is built for FVP with LOG_LEVEL=LOG_LEVEL_VERBOSE, resulted
in saving 384 bytes of RO data and increase of 8 bytes of RW data. The
framework also adds about 108 bytes of code to the release build of FVP.
Fixes ARM-software/tf-issues#462
Change-Id: I476013d9c3deedfdd4c8b0b0f125665ba6250554
Co-authored-by: Eleanor Bonnici <Eleanor.bonnici@arm.com>
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/Makefile b/Makefile
index 0a64514..f69a046 100644
--- a/Makefile
+++ b/Makefile
@@ -162,11 +162,13 @@
include lib/stdlib/stdlib.mk
BL_COMMON_SOURCES += common/bl_common.c \
+ common/tf_log.c \
common/tf_printf.c \
common/tf_snprintf.c \
common/${ARCH}/debug.S \
lib/${ARCH}/cache_helpers.S \
lib/${ARCH}/misc_helpers.S \
+ plat/common/plat_log_common.c \
plat/common/${ARCH}/plat_common.c \
plat/common/${ARCH}/platform_helpers.S \
${COMPILER_RT_SRCS} \
diff --git a/common/tf_log.c b/common/tf_log.c
new file mode 100644
index 0000000..54c0a43
--- /dev/null
+++ b/common/tf_log.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <debug.h>
+#include <platform.h>
+
+/* Set the default maximum log level to the `LOG_LEVEL` build flag */
+static unsigned int max_log_level = LOG_LEVEL;
+
+/*
+ * The common log function which is invoked by ARM Trusted Firmware code.
+ * This function should not be directly invoked and is meant to be
+ * only used by the log macros defined in debug.h. The function
+ * expects the first character in the format string to be one of the
+ * LOG_MARKER_* macros defined in debug.h.
+ */
+void tf_log(const char *fmt, ...)
+{
+ unsigned int log_level;
+ va_list args;
+ const char *prefix_str;
+
+ /* We expect the LOG_MARKER_* macro as the first character */
+ log_level = fmt[0];
+
+ /* Verify that log_level is one of LOG_MARKER_* macro defined in debug.h */
+ assert(log_level && log_level <= LOG_LEVEL_VERBOSE);
+ assert(log_level % 10 == 0);
+
+ if (log_level > max_log_level)
+ return;
+
+ prefix_str = plat_log_get_prefix(log_level);
+
+ if (prefix_str != NULL)
+ tf_string_print(prefix_str);
+
+ va_start(args, fmt);
+ tf_vprintf(fmt+1, args);
+ va_end(args);
+}
+
+/*
+ * The helper function to set the log level dynamically by platform. The
+ * maximum log level is determined by `LOG_LEVEL` build flag at compile time
+ * and this helper can set a lower log level than the one at compile.
+ */
+void tf_log_set_max_level(unsigned int log_level)
+{
+ assert(log_level <= LOG_LEVEL_VERBOSE);
+ assert((log_level % 10) == 0);
+
+ /* Cap log_level to the compile time maximum. */
+ if (log_level < LOG_LEVEL)
+ max_log_level = log_level;
+
+}
diff --git a/docs/porting-guide.rst b/docs/porting-guide.rst
index c8d61ed..9798566 100644
--- a/docs/porting-guide.rst
+++ b/docs/porting-guide.rst
@@ -1014,6 +1014,21 @@
next image. This function is currently invoked in BL2 to flush this information
to the next BL image, when LOAD\_IMAGE\_V2 is enabled.
+Function : plat\_log\_get\_prefix()
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+::
+
+ Argument : unsigned int
+ Return : const char *
+
+This function defines the prefix string corresponding to the `log_level` to be
+prepended to all the log output from ARM Trusted Firmware. The `log_level`
+(argument) will correspond to one of the standard log levels defined in
+debug.h. The platform can override the common implementation to define a
+different prefix string for the log output. The implementation should be
+robust to future changes that increase the number of log levels.
+
Modifications specific to a Boot Loader stage
---------------------------------------------
diff --git a/include/common/debug.h b/include/common/debug.h
index b858241..3f0f84a 100644
--- a/include/common/debug.h
+++ b/include/common/debug.h
@@ -27,47 +27,59 @@
#include <stdarg.h>
#include <stdio.h>
+/*
+ * Define Log Markers corresponding to each log level which will
+ * be embedded in the format string and is expected by tf_log() to determine
+ * the log level.
+ */
+#define LOG_MARKER_ERROR "\xa" /* 10 */
+#define LOG_MARKER_NOTICE "\x14" /* 20 */
+#define LOG_MARKER_WARNING "\x1e" /* 30 */
+#define LOG_MARKER_INFO "\x28" /* 40 */
+#define LOG_MARKER_VERBOSE "\x32" /* 50 */
+
#if LOG_LEVEL >= LOG_LEVEL_NOTICE
-# define NOTICE(...) tf_printf("NOTICE: " __VA_ARGS__)
+# define NOTICE(...) tf_log(LOG_MARKER_NOTICE __VA_ARGS__)
#else
# define NOTICE(...)
#endif
#if LOG_LEVEL >= LOG_LEVEL_ERROR
-# define ERROR(...) tf_printf("ERROR: " __VA_ARGS__)
+# define ERROR(...) tf_log(LOG_MARKER_ERROR __VA_ARGS__)
#else
# define ERROR(...)
#endif
#if LOG_LEVEL >= LOG_LEVEL_WARNING
-# define WARN(...) tf_printf("WARNING: " __VA_ARGS__)
+# define WARN(...) tf_log(LOG_MARKER_WARNING __VA_ARGS__)
#else
# define WARN(...)
#endif
#if LOG_LEVEL >= LOG_LEVEL_INFO
-# define INFO(...) tf_printf("INFO: " __VA_ARGS__)
+# define INFO(...) tf_log(LOG_MARKER_INFO __VA_ARGS__)
#else
# define INFO(...)
#endif
#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
-# define VERBOSE(...) tf_printf("VERBOSE: " __VA_ARGS__)
+# define VERBOSE(...) tf_log(LOG_MARKER_VERBOSE __VA_ARGS__)
#else
# define VERBOSE(...)
#endif
-
void __dead2 do_panic(void);
#define panic() do_panic()
/* Function called when stack protection check code detects a corrupted stack */
void __dead2 __stack_chk_fail(void);
+void tf_log(const char *fmt, ...) __printflike(1, 2);
void tf_printf(const char *fmt, ...) __printflike(1, 2);
int tf_snprintf(char *s, size_t n, const char *fmt, ...) __printflike(3, 4);
void tf_vprintf(const char *fmt, va_list args);
void tf_string_print(const char *str);
+void tf_log_set_max_level(unsigned int log_level);
#endif /* __ASSEMBLY__ */
#endif /* __DEBUG_H__ */
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index bd721bb..e189f64 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -79,6 +79,7 @@
int plat_crash_console_flush(void);
void plat_error_handler(int err) __dead2;
void plat_panic_handler(void) __dead2;
+const char *plat_log_get_prefix(unsigned int log_level);
/*******************************************************************************
* Mandatory BL1 functions
diff --git a/plat/common/plat_log_common.c b/plat/common/plat_log_common.c
new file mode 100644
index 0000000..30dcb12
--- /dev/null
+++ b/plat/common/plat_log_common.c
@@ -0,0 +1,25 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <debug.h>
+#include <platform.h>
+
+/* Allow platforms to override the log prefix string */
+#pragma weak plat_log_get_prefix
+
+static const char *prefix_str[] = {
+ "ERROR: ", "NOTICE: ", "WARNING: ", "INFO: ", "VERBOSE: "};
+
+const char *plat_log_get_prefix(unsigned int log_level)
+{
+ if (log_level < LOG_LEVEL_ERROR)
+ log_level = LOG_LEVEL_ERROR;
+ else if (log_level > LOG_LEVEL_VERBOSE)
+ log_level = LOG_LEVEL_VERBOSE;
+
+ return prefix_str[(log_level/10) - 1];
+}