Merge tag 'trace-v5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing and bootconfig updates:
 "Fixes and changes to bootconfig before it goes live in a release.

  Change in API of bootconfig (before it comes live in a release):
  - Have a magic value "BOOTCONFIG" in initrd to know a bootconfig
    exists
  - Set CONFIG_BOOT_CONFIG to 'n' by default
  - Show error if "bootconfig" on cmdline but not compiled in
  - Prevent redefining the same value
  - Have a way to append values
  - Added a SELECT BLK_DEV_INITRD to fix a build failure

  Synthetic event fixes:
  - Switch to raw_smp_processor_id() for recording CPU value in preempt
    section. (No care for what the value actually is)
  - Fix samples always recording u64 values
  - Fix endianess
  - Check number of values matches number of fields
  - Fix a printing bug

  Fix of trace_printk() breaking postponed start up tests

  Make a function static that is only used in a single file"

* tag 'trace-v5.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  bootconfig: Fix CONFIG_BOOTTIME_TRACING dependency issue
  bootconfig: Add append value operator support
  bootconfig: Prohibit re-defining value on same key
  bootconfig: Print array as multiple commands for legacy command line
  bootconfig: Reject subkey and value on same parent key
  tools/bootconfig: Remove unneeded error message silencer
  bootconfig: Add bootconfig magic word for indicating bootconfig explicitly
  bootconfig: Set CONFIG_BOOT_CONFIG=n by default
  tracing: Clear trace_state when starting trace
  bootconfig: Mark boot_config_checksum() static
  tracing: Disable trace_printk() on post poned tests
  tracing: Have synthetic event test use raw_smp_processor_id()
  tracing: Fix number printing bug in print_synth_event()
  tracing: Check that number of vals matches number of synth event fields
  tracing: Make synth_event trace functions endian-correct
  tracing: Make sure synth_event_trace() example always uses u64

Author: torvalds

Documentation/admin-guide/bootconfig.rst

@@ -62,6 +62,30 @@ Or more shorter, written as following::
 In both styles, same key words are automatically merged when parsing it
 at boot time. So you can append similar trees or key-values.
 
+Same-key Values
+---------------
+
+It is prohibited that two or more values or arrays share a same-key.
+For example,::
+
+ foo = bar, baz
+ foo = qux  # !ERROR! we can not re-define same key
+
+If you want to append the value to existing key as an array member,
+you can use ``+=`` operator. For example::
+
+ foo = bar, baz
+ foo += qux
+
+In this case, the key ``foo`` has ``bar``, ``baz`` and ``qux``.
+
+However, a sub-key and a value can not co-exist under a parent key.
+For example, following config is NOT allowed.::
+
+ foo = value1
+ foo.bar = value2 # !ERROR! subkey "bar" and value "value1" can NOT co-exist
+
+
 Comments
 --------
 
@@ -102,9 +126,13 @@ Boot Kernel With a Boot Config
 ==============================
 
 Since the boot configuration file is loaded with initrd, it will be added
-to the end of the initrd (initramfs) image file. The Linux kernel decodes
-the last part of the initrd image in memory to get the boot configuration
-data.
+to the end of the initrd (initramfs) image file with size, checksum and
+12-byte magic word as below.
+
+[initrd][bootconfig][size(u32)][checksum(u32)][#BOOTCONFIG\n]
+
+The Linux kernel decodes the last part of the initrd image in memory to
+get the boot configuration data.
 Because of this "piggyback" method, there is no need to change or
 update the boot loader and the kernel image itself.
 

include/linux/bootconfig.h

@@ -10,6 +10,9 @@
 #include <linux/kernel.h>
 #include <linux/types.h>
 
+#define BOOTCONFIG_MAGIC	"#BOOTCONFIG\n"
+#define BOOTCONFIG_MAGIC_LEN	12
+
 /* XBC tree node */
 struct xbc_node {
 	u16 next;

init/Kconfig

@@ -1226,13 +1226,12 @@ endif
 
 config BOOT_CONFIG
 	bool "Boot config support"
-	depends on BLK_DEV_INITRD
-	default y
+	select BLK_DEV_INITRD
 	help
 	  Extra boot config allows system admin to pass a config file as
 	  complemental extension of kernel cmdline when booting.
 	  The boot config file must be attached at the end of initramfs
-	  with checksum and size.
+	  with checksum, size and magic word.
 	  See <file:Documentation/admin-guide/bootconfig.rst> for details.
 
 	  If unsure, say Y.

init/main.c

@@ -268,7 +268,6 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
 {
 	struct xbc_node *knode, *vnode;
 	char *end = buf + size;
-	char c = '\"';
 	const char *val;
 	int ret;
 
@@ -279,25 +278,20 @@ static int __init xbc_snprint_cmdline(char *buf, size_t size,
 			return ret;
 
 		vnode = xbc_node_get_child(knode);
-		ret = snprintf(buf, rest(buf, end), "%s%c", xbc_namebuf,
-				vnode ? '=' : ' ');
-		if (ret < 0)
-			return ret;
-		buf += ret;
-		if (!vnode)
+		if (!vnode) {
+			ret = snprintf(buf, rest(buf, end), "%s ", xbc_namebuf);
+			if (ret < 0)
+				return ret;
+			buf += ret;
 			continue;
-
-		c = '\"';
+		}
 		xbc_array_for_each_value(vnode, val) {
-			ret = snprintf(buf, rest(buf, end), "%c%s", c, val);
+			ret = snprintf(buf, rest(buf, end), "%s=\"%s\" ",
+				       xbc_namebuf, val);
 			if (ret < 0)
 				return ret;
 			buf += ret;
-			c = ',';
 		}
-		if (rest(buf, end) > 2)
-			strcpy(buf, "\" ");
-		buf += 2;
 	}
 
 	return buf - (end - size);
@@ -335,7 +329,7 @@ static char * __init xbc_make_cmdline(const char *key)
 	return new_cmdline;
 }
 
-u32 boot_config_checksum(unsigned char *p, u32 size)
+static u32 boot_config_checksum(unsigned char *p, u32 size)
 {
 	u32 ret = 0;
 
@@ -374,7 +368,11 @@ static void __init setup_boot_config(const char *cmdline)
 	if (!initrd_end)
 		goto not_found;
 
-	hdr = (u32 *)(initrd_end - 8);
+	data = (char *)initrd_end - BOOTCONFIG_MAGIC_LEN;
+	if (memcmp(data, BOOTCONFIG_MAGIC, BOOTCONFIG_MAGIC_LEN))
+		goto not_found;
+
+	hdr = (u32 *)(data - 8);
 	size = hdr[0];
 	csum = hdr[1];
 
@@ -418,6 +416,14 @@ static void __init setup_boot_config(const char *cmdline)
 }
 #else
 #define setup_boot_config(cmdline)	do { } while (0)
+
+static int __init warn_bootconfig(char *str)
+{
+	pr_warn("WARNING: 'bootconfig' found on the kernel command line but CONFIG_BOOTCONFIG is not set.\n");
+	return 0;
+}
+early_param("bootconfig", warn_bootconfig);
+
 #endif
 
 /* Change NUL term back to "=", to make "param" the whole string. */

kernel/trace/Kconfig

@@ -143,8 +143,8 @@ if FTRACE
 
 config BOOTTIME_TRACING
 	bool "Boot-time Tracing support"
-	depends on BOOT_CONFIG && TRACING
-	default y
+	depends on TRACING
+	select BOOT_CONFIG
 	help
 	  Enable developer to setup ftrace subsystem via supplemental
 	  kernel cmdline at boot time for debugging (tracing) driver

kernel/trace/synth_event_gen_test.c

@@ -111,11 +111,11 @@ static int __init test_gen_synth_cmd(void)
 	/* Create some bogus values just for testing */
 
 	vals[0] = 777;			/* next_pid_field */
-	vals[1] = (u64)"hula hoops";	/* next_comm_field */
+	vals[1] = (u64)(long)"hula hoops";	/* next_comm_field */
 	vals[2] = 1000000;		/* ts_ns */
 	vals[3] = 1000;			/* ts_ms */
-	vals[4] = smp_processor_id();	/* cpu */
-	vals[5] = (u64)"thneed";	/* my_string_field */
+	vals[4] = raw_smp_processor_id(); /* cpu */
+	vals[5] = (u64)(long)"thneed";	/* my_string_field */
 	vals[6] = 598;			/* my_int_field */
 
 	/* Now generate a gen_synth_test event */
@@ -218,11 +218,11 @@ static int __init test_empty_synth_event(void)
 	/* Create some bogus values just for testing */
 
 	vals[0] = 777;			/* next_pid_field */
-	vals[1] = (u64)"tiddlywinks";	/* next_comm_field */
+	vals[1] = (u64)(long)"tiddlywinks";	/* next_comm_field */
 	vals[2] = 1000000;		/* ts_ns */
 	vals[3] = 1000;			/* ts_ms */
-	vals[4] = smp_processor_id();	/* cpu */
-	vals[5] = (u64)"thneed_2.0";	/* my_string_field */
+	vals[4] = raw_smp_processor_id(); /* cpu */
+	vals[5] = (u64)(long)"thneed_2.0";	/* my_string_field */
 	vals[6] = 399;			/* my_int_field */
 
 	/* Now trace an empty_synth_test event */
@@ -290,11 +290,11 @@ static int __init test_create_synth_event(void)
 	/* Create some bogus values just for testing */
 
 	vals[0] = 777;			/* next_pid_field */
-	vals[1] = (u64)"tiddlywinks";	/* next_comm_field */
+	vals[1] = (u64)(long)"tiddlywinks";	/* next_comm_field */
 	vals[2] = 1000000;		/* ts_ns */
 	vals[3] = 1000;			/* ts_ms */
-	vals[4] = smp_processor_id();	/* cpu */
-	vals[5] = (u64)"thneed";	/* my_string_field */
+	vals[4] = raw_smp_processor_id(); /* cpu */
+	vals[5] = (u64)(long)"thneed";	/* my_string_field */
 	vals[6] = 398;			/* my_int_field */
 
 	/* Now generate a create_synth_test event */
@@ -330,7 +330,7 @@ static int __init test_add_next_synth_val(void)
 		goto out;
 
 	/* next_comm_field */
-	ret = synth_event_add_next_val((u64)"slinky", &trace_state);
+	ret = synth_event_add_next_val((u64)(long)"slinky", &trace_state);
 	if (ret)
 		goto out;
 
@@ -345,12 +345,12 @@ static int __init test_add_next_synth_val(void)
 		goto out;
 
 	/* cpu */
-	ret = synth_event_add_next_val(smp_processor_id(), &trace_state);
+	ret = synth_event_add_next_val(raw_smp_processor_id(), &trace_state);
 	if (ret)
 		goto out;
 
 	/* my_string_field */
-	ret = synth_event_add_next_val((u64)"thneed_2.01", &trace_state);
+	ret = synth_event_add_next_val((u64)(long)"thneed_2.01", &trace_state);
 	if (ret)
 		goto out;
 
@@ -388,20 +388,20 @@ static int __init test_add_synth_val(void)
 	if (ret)
 		goto out;
 
-	ret = synth_event_add_val("cpu", smp_processor_id(), &trace_state);
+	ret = synth_event_add_val("cpu", raw_smp_processor_id(), &trace_state);
 	if (ret)
 		goto out;
 
 	ret = synth_event_add_val("next_pid_field", 777, &trace_state);
 	if (ret)
 		goto out;
 
-	ret = synth_event_add_val("next_comm_field", (u64)"silly putty",
+	ret = synth_event_add_val("next_comm_field", (u64)(long)"silly putty",
 				  &trace_state);
 	if (ret)
 		goto out;
 
-	ret = synth_event_add_val("my_string_field", (u64)"thneed_9",
+	ret = synth_event_add_val("my_string_field", (u64)(long)"thneed_9",
 				  &trace_state);
 	if (ret)
 		goto out;
@@ -423,13 +423,13 @@ static int __init test_trace_synth_event(void)
 
 	/* Trace some bogus values just for testing */
 	ret = synth_event_trace(create_synth_test, 7,	/* number of values */
-				444,			/* next_pid_field */
-				(u64)"clackers",	/* next_comm_field */
-				1000000,		/* ts_ns */
-				1000,			/* ts_ms */
-				smp_processor_id(),	/* cpu */
-				(u64)"Thneed",		/* my_string_field */
-				999);			/* my_int_field */
+				(u64)444,		/* next_pid_field */
+				(u64)(long)"clackers",	/* next_comm_field */
+				(u64)1000000,		/* ts_ns */
+				(u64)1000,		/* ts_ms */
+				(u64)raw_smp_processor_id(), /* cpu */
+				(u64)(long)"Thneed",	/* my_string_field */
+				(u64)999);		/* my_int_field */
 	return ret;
 }
 

kernel/trace/trace.c

@@ -1837,6 +1837,7 @@ static __init int init_trace_selftests(void)
 
 	pr_info("Running postponed tracer tests:\n");
 
+	tracing_selftest_running = true;
 	list_for_each_entry_safe(p, n, &postponed_selftests, list) {
 		/* This loop can take minutes when sanitizers are enabled, so
 		 * lets make sure we allow RCU processing.
@@ -1859,6 +1860,7 @@ static __init int init_trace_selftests(void)
 		list_del(&p->list);
 		kfree(p);
 	}
+	tracing_selftest_running = false;
 
  out:
 	mutex_unlock(&trace_types_lock);