From ceabef7dd71720aef58bd182943352c9c307a3de Mon Sep 17 00:00:00 2001
From: Orson Zhai <orson.zhai@unisoc.com>
Date: Sun, 7 Jun 2020 21:40:14 -0700
Subject: dynamic_debug: add an option to enable dynamic debug for modules only

Instead of enabling dynamic debug globally with CONFIG_DYNAMIC_DEBUG,
CONFIG_DYNAMIC_DEBUG_CORE will only enable core function of dynamic
debug.  With the DYNAMIC_DEBUG_MODULE defined for any modules, dynamic
debug will be tied to them.

This is useful for people who only want to enable dynamic debug for
kernel modules without worrying about kernel image size and memory
consumption is increasing too much.

[orson.zhai@unisoc.com: v2]
  Link: http://lkml.kernel.org/r/1587408228-10861-1-git-send-email-orson.unisoc@gmail.com

Signed-off-by: Orson Zhai <orson.zhai@unisoc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Petr Mladek <pmladek@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Link: http://lkml.kernel.org/r/1586521984-5890-1-git-send-email-orson.unisoc@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 lib/Kconfig.debug   | 12 ++++++++++++
 lib/Makefile        |  2 +-
 lib/dynamic_debug.c |  9 +++++++--
 3 files changed, 20 insertions(+), 3 deletions(-)

(limited to 'lib')

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 9bd4eb7f5ec1..333e878d8af9 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -99,6 +99,7 @@ config DYNAMIC_DEBUG
 	default n
 	depends on PRINTK
 	depends on (DEBUG_FS || PROC_FS)
+	select DYNAMIC_DEBUG_CORE
 	help
 
 	  Compiles debug level messages into the kernel, which would not
@@ -165,6 +166,17 @@ config DYNAMIC_DEBUG
 	  See Documentation/admin-guide/dynamic-debug-howto.rst for additional
 	  information.
 
+config DYNAMIC_DEBUG_CORE
+	bool "Enable core function of dynamic debug support"
+	depends on PRINTK
+	depends on (DEBUG_FS || PROC_FS)
+	help
+	  Enable core functional support of dynamic debug. It is useful
+	  when you want to tie dynamic debug to your kernel modules with
+	  DYNAMIC_DEBUG_MODULE defined for each of them, especially for
+	  the case of embedded system where the kernel image size is
+	  sensitive for people.
+
 config SYMBOLIC_ERRNAME
 	bool "Support symbolic error names in printf"
 	default y if PRINTK
diff --git a/lib/Makefile b/lib/Makefile
index 32f19b4d1d2a..315516fa4ef4 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -190,7 +190,7 @@ lib-$(CONFIG_GENERIC_BUG) += bug.o
 
 obj-$(CONFIG_HAVE_ARCH_TRACEHOOK) += syscall.o
 
-obj-$(CONFIG_DYNAMIC_DEBUG) += dynamic_debug.o
+obj-$(CONFIG_DYNAMIC_DEBUG_CORE) += dynamic_debug.o
 obj-$(CONFIG_SYMBOLIC_ERRNAME) += errname.o
 
 obj-$(CONFIG_NLATTR) += nlattr.o
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 8f199f403ab5..321437bbf87d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1032,8 +1032,13 @@ static int __init dynamic_debug_init(void)
 	int verbose_bytes = 0;
 
 	if (&__start___verbose == &__stop___verbose) {
-		pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
-		return 1;
+		if (IS_ENABLED(CONFIG_DYNAMIC_DEBUG)) {
+			pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n");
+			return 1;
+		}
+		pr_info("Ignore empty _ddebug table in a CONFIG_DYNAMIC_DEBUG_CORE build\n");
+		ddebug_init_success = 1;
+		return 0;
 	}
 	iter = __start___verbose;
 	modname = iter->modname;
-- 
cgit v1.2.3


From 4f2f682d89d83fb6194562321d875253282d8496 Mon Sep 17 00:00:00 2001
From: Vlastimil Babka <vbabka@suse.cz>
Date: Sun, 7 Jun 2020 21:40:38 -0700
Subject: lib/test_sysctl: support testing of sysctl. boot parameter

Testing is done by a new parameter debug.test_sysctl.boot_int which
defaults to 0 and it's expected that the tester passes a boot parameter
that sets it to 1.  The test checks if it's set to 1.

To distinguish true failure from parameter not being set, the test
checks /proc/cmdline for the expected parameter, and whether test_sysctl
is built-in and not a module.

[vbabka@suse.cz: skip the new test if boot_int sysctl is not present]
  Link: http://lkml.kernel.org/r/305af605-1e60-cf84-fada-6ce1ca37c102@suse.cz

Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christian Brauner <christian.brauner@ubuntu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Eric W . Biederman" <ebiederm@xmission.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Guilherme G . Piccoli" <gpiccoli@canonical.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Cc: Ivan Teterevkov <ivan.teterevkov@nutanix.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20200427180433.7029-6-vbabka@suse.cz
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 lib/test_sysctl.c                        | 13 ++++++++++
 tools/testing/selftests/sysctl/sysctl.sh | 42 ++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+)

(limited to 'lib')

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 566dad3f4196..84eaae22d3a6 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -44,6 +44,8 @@ struct test_sysctl_data {
 	int int_0002;
 	int int_0003[4];
 
+	int boot_int;
+
 	unsigned int uint_0001;
 
 	char string_0001[65];
@@ -61,6 +63,8 @@ static struct test_sysctl_data test_data = {
 	.int_0003[2] = 2,
 	.int_0003[3] = 3,
 
+	.boot_int = 0,
+
 	.uint_0001 = 314,
 
 	.string_0001 = "(none)",
@@ -91,6 +95,15 @@ static struct ctl_table test_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec,
 	},
+	{
+		.procname	= "boot_int",
+		.data		= &test_data.boot_int,
+		.maxlen		= sizeof(test_data.boot_int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec,
+		.extra1		= SYSCTL_ZERO,
+		.extra2         = SYSCTL_ONE,
+	},
 	{
 		.procname	= "uint_0001",
 		.data		= &test_data.uint_0001,
diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index a4262955d30f..0aa8a86140e9 100755
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -39,6 +39,7 @@ ALL_TESTS="$ALL_TESTS 0003:1:1:int_0002"
 ALL_TESTS="$ALL_TESTS 0004:1:1:uint_0001"
 ALL_TESTS="$ALL_TESTS 0005:3:1:int_0003"
 ALL_TESTS="$ALL_TESTS 0006:50:1:bitmap_0001"
+ALL_TESTS="$ALL_TESTS 0007:1:1:boot_int"
 
 test_modprobe()
 {
@@ -752,6 +753,46 @@ sysctl_test_0006()
 	run_bitmaptest
 }
 
+sysctl_test_0007()
+{
+	TARGET="${SYSCTL}/boot_int"
+	if [ ! -f $TARGET ]; then
+		echo "Skipping test for $TARGET as it is not present ..."
+		return $ksft_skip
+	fi
+
+	if [ -d $DIR ]; then
+		echo "Boot param test only possible sysctl_test is built-in, not module:"
+		cat $TEST_DIR/config >&2
+		return $ksft_skip
+	fi
+
+	echo -n "Testing if $TARGET is set to 1 ..."
+	ORIG=$(cat "${TARGET}")
+
+	if [ x$ORIG = "x1" ]; then
+		echo "ok"
+		return 0
+	fi
+	echo "FAIL"
+	echo "Checking if /proc/cmdline contains setting of the expected parameter ..."
+	if [ ! -f /proc/cmdline ]; then
+		echo "/proc/cmdline does not exist, test inconclusive"
+		return 0
+	fi
+
+	FOUND=$(grep -c "sysctl[./]debug[./]test_sysctl[./]boot_int=1" /proc/cmdline)
+	if [ $FOUND = "1" ]; then
+		echo "Kernel param found but $TARGET is not 1, TEST FAILED"
+		rc=1
+		test_rc
+	fi
+
+	echo "Skipping test, expected kernel parameter missing."
+	echo "To perform this test, make sure kernel is booted with parameter: sysctl.debug.test_sysctl.boot_int=1"
+	return $ksft_skip
+}
+
 list_tests()
 {
 	echo "Test ID list:"
@@ -766,6 +807,7 @@ list_tests()
 	echo "0004 x $(get_test_count 0004) - tests proc_douintvec()"
 	echo "0005 x $(get_test_count 0005) - tests proc_douintvec() array"
 	echo "0006 x $(get_test_count 0006) - tests proc_do_large_bitmap()"
+	echo "0007 x $(get_test_count 0007) - tests setting sysctl from kernel boot param"
 }
 
 usage()
-- 
cgit v1.2.3