From 13854bd88ca72728ea6a6b2bd1762a27fb39c534 Mon Sep 17 00:00:00 2001 From: Orson Zhai Date: Fri, 10 Apr 2020 19:46:30 +0800 Subject: [PATCH] FROMLIST: BACKPORT: 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. Change-Id: I27de392de2e2545afa8dcbe096deadb252537905 Signed-off-by: Orson Zhai Acked-by: Greg Kroah-Hartman Bug: 145162121 Link: https://lore.kernel.org/lkml/1587408228-10861-1-git-send-email-orson.unisoc@gmail.com/ --- Documentation/admin-guide/dynamic-debug-howto.rst | 5 +++++ include/linux/device.h | 6 ++++-- include/linux/dynamic_debug.h | 2 +- include/linux/net.h | 3 ++- include/linux/netdevice.h | 6 ++++-- include/linux/printk.h | 14 +++++++++----- include/rdma/ib_verbs.h | 6 ++++-- lib/Kconfig.debug | 12 ++++++++++++ lib/Makefile | 2 +- lib/dynamic_debug.c | 9 +++++++-- 10 files changed, 49 insertions(+), 16 deletions(-) diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst index 0dc2eb8e44e5..1012bd9305e9 100644 --- a/Documentation/admin-guide/dynamic-debug-howto.rst +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -13,6 +13,11 @@ kernel code to obtain additional kernel information. Currently, if ``print_hex_dump_debug()``/``print_hex_dump_bytes()`` calls can be dynamically enabled per-callsite. +If you do not want to enable dynamic debug globally (i.e. in some embedded +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any +modules which you'd like to dynamically debug later. + If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is just shortcut for ``print_hex_dump(KERN_DEBUG)``. diff --git a/include/linux/device.h b/include/linux/device.h index 826e8332e16f..807b57889169 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1812,7 +1812,8 @@ void _dev_info(const struct device *dev, const char *fmt, ...) #define dev_info(dev, fmt, ...) \ _dev_info(dev, dev_fmt(fmt), ##__VA_ARGS__) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define dev_dbg(dev, fmt, ...) \ dynamic_dev_dbg(dev, dev_fmt(fmt), ##__VA_ARGS__) #elif defined(DEBUG) @@ -1884,7 +1885,8 @@ do { \ dev_level_ratelimited(dev_notice, dev, fmt, ##__VA_ARGS__) #define dev_info_ratelimited(dev, fmt, ...) \ dev_level_ratelimited(dev_info, dev, fmt, ##__VA_ARGS__) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) /* descriptor check is first to prevent flooding with "callbacks suppressed" */ #define dev_dbg_ratelimited(dev, fmt, ...) \ do { \ diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 4cf02ecd67de..abcd5fde30eb 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -48,7 +48,7 @@ struct _ddebug { -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG_CORE) int ddebug_add_module(struct _ddebug *tab, unsigned int n, const char *modname); extern int ddebug_remove_module(const char *mod_name); diff --git a/include/linux/net.h b/include/linux/net.h index 9cafb5f353a9..9dde5b2ca4bc 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -263,7 +263,8 @@ do { \ net_ratelimited_function(pr_warn, fmt, ##__VA_ARGS__) #define net_info_ratelimited(fmt, ...) \ net_ratelimited_function(pr_info, fmt, ##__VA_ARGS__) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define net_dbg_ratelimited(fmt, ...) \ do { \ DEFINE_DYNAMIC_DEBUG_METADATA(descriptor, fmt); \ diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h index b580a35f50ea..1575a85d076f 100644 --- a/include/linux/netdevice.h +++ b/include/linux/netdevice.h @@ -4753,7 +4753,8 @@ do { \ #define MODULE_ALIAS_NETDEV(device) \ MODULE_ALIAS("netdev-" device) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define netdev_dbg(__dev, format, args...) \ do { \ dynamic_netdev_dbg(__dev, format, ##args); \ @@ -4823,7 +4824,8 @@ do { \ #define netif_info(priv, type, dev, fmt, args...) \ netif_level(info, priv, type, dev, fmt, ##args) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define netif_dbg(priv, type, netdev, format, args...) \ do { \ if (netif_msg_##type(priv)) \ diff --git a/include/linux/printk.h b/include/linux/printk.h index c09d67edda3a..20f088c2acc4 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -291,8 +291,9 @@ extern int kptr_restrict; /* * These can be used to print at the various log levels. * All of these will print unconditionally, although note that pr_debug() - * and other debug macros are compiled out unless either DEBUG is defined - * or CONFIG_DYNAMIC_DEBUG is set. + * and other debug macros are compiled out unless either DEBUG is defined, + * CONFIG_DYNAMIC_DEBUG is set, or CONFIG_DYNAMIC_DEBUG_CORE is set when + * DYNAMIC_DEBUG_MODULE being defined for any modules. */ #define pr_emerg(fmt, ...) \ printk(KERN_EMERG pr_fmt(fmt), ##__VA_ARGS__) @@ -328,7 +329,8 @@ extern int kptr_restrict; /* If you are writing a driver, please use dev_dbg instead */ -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #include /* dynamic_pr_debug() uses pr_fmt() internally so we don't need it here */ @@ -454,7 +456,8 @@ extern int kptr_restrict; #endif /* If you are writing a driver, please use dev_dbg instead */ -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) /* descriptor check is first to prevent flooding with "callbacks suppressed" */ #define pr_debug_ratelimited(fmt, ...) \ do { \ @@ -501,7 +504,8 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type, #endif -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define print_hex_dump_debug(prefix_str, prefix_type, rowsize, \ groupsize, buf, len, ascii) \ dynamic_hex_dump(prefix_str, prefix_type, rowsize, \ diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h index 30d50528d710..83a66c931487 100644 --- a/include/rdma/ib_verbs.h +++ b/include/rdma/ib_verbs.h @@ -95,7 +95,8 @@ void ibdev_notice(const struct ib_device *ibdev, const char *format, ...); __printf(2, 3) __cold void ibdev_info(const struct ib_device *ibdev, const char *format, ...); -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) #define ibdev_dbg(__dev, format, args...) \ dynamic_ibdev_dbg(__dev, format, ##args) #else @@ -128,7 +129,8 @@ do { \ #define ibdev_info_ratelimited(ibdev, fmt, ...) \ ibdev_level_ratelimited(ibdev_info, ibdev, fmt, ##__VA_ARGS__) -#if defined(CONFIG_DYNAMIC_DEBUG) +#if defined(CONFIG_DYNAMIC_DEBUG) || \ + (defined(CONFIG_DYNAMIC_DEBUG_CORE) && defined(DYNAMIC_DEBUG_MODULE)) /* descriptor check is first to prevent flooding with "callbacks suppressed" */ #define ibdev_dbg_ratelimited(ibdev, fmt, ...) \ do { \ diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 2b6cba47c76d..36ff9065eb4d 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. + endmenu # "printk and dmesg options" menu "Compile-time checks and compiler options" diff --git a/lib/Makefile b/lib/Makefile index c35ea2ebb72e..31600c9802b7 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -181,7 +181,7 @@ 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_NLATTR) += nlattr.o diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c index c220c1891729..e02395c41c1b 100644 --- a/lib/dynamic_debug.c +++ b/lib/dynamic_debug.c @@ -1024,8 +1024,13 @@ 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;