From 8522f6b760ca588928eede740d5d69dd1e936b49 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 28 Feb 2024 15:00:02 +0100 Subject: printk: Let no_printk() use _printk() When printk-indexing is enabled, each printk() invocation emits a pi_entry structure, containing the format string and other information related to its location in the kernel sources. This is even true for no_printk(): while the actual code to print the message is optimized out by the compiler due to the always-false check, the pi_entry structure is still emitted. As the main purpose of no_printk() is to provide a helper to maintain printf()-style format checking when debugging is disabled, this leads to the inclusion in the index of lots of printk formats that cannot be emitted by the current kernel. Fix this by switching no_printk() from printk() to _printk(). This reduces the size of an arm64 defconfig kernel with CONFIG_PRINTK_INDEX=y by 576 KiB. Fixes: 337015573718b161 ("printk: Userspace format indexing support") Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Reviewed-by: Xiubo Li Reviewed-by: Chris Down Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/56cf92edccffea970e1f40a075334dd6cf5bb2a4.1709127473.git.geert+renesas@glider.be Signed-off-by: Petr Mladek --- include/linux/printk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/printk.h b/include/linux/printk.h index 955e31860095..2fde40cc9677 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -126,7 +126,7 @@ struct va_format { #define no_printk(fmt, ...) \ ({ \ if (0) \ - printk(fmt, ##__VA_ARGS__); \ + _printk(fmt, ##__VA_ARGS__); \ 0; \ }) -- cgit v1.2.3 From c26ec799042a3888935d59b599f33e41efedf5f8 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 28 Feb 2024 15:00:03 +0100 Subject: dev_printk: Add and use dev_no_printk() When printk-indexing is enabled, each dev_printk() invocation emits a pi_entry structure. This is even true when the dev_printk() is protected by an always-false check, as is typically the case for debug messages: while the actual code to print the message is optimized out by the compiler, the pi_entry structure is still emitted. Avoid emitting pi_entry structures for unavailable dev_printk() kernel messages by: 1. Introducing a dev_no_printk() helper, mimicked after the existing no_printk() helper, which calls _dev_printk() instead of dev_printk(), 2. Replacing all "if (0) dev_printk(...)" constructs by calls to the new helper. This reduces the size of an arm64 defconfig kernel with CONFIG_PRINTK_INDEX=y by 957 KiB. Fixes: ad7d61f159db7397 ("printk: index: Add indexing support to dev_printk") Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Reviewed-by: Xiubo Li Reviewed-by: Chris Down Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/8583d54f1687c801c6cda8edddf2cf0344c6e883.1709127473.git.geert+renesas@glider.be Signed-off-by: Petr Mladek --- include/linux/dev_printk.h | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dev_printk.h b/include/linux/dev_printk.h index 6bfe70decc9f..ae80a303c216 100644 --- a/include/linux/dev_printk.h +++ b/include/linux/dev_printk.h @@ -129,6 +129,16 @@ void _dev_info(const struct device *dev, const char *fmt, ...) _dev_printk(level, dev, fmt, ##__VA_ARGS__); \ }) +/* + * Dummy dev_printk for disabled debugging statements to use whilst maintaining + * gcc's format checking. + */ +#define dev_no_printk(level, dev, fmt, ...) \ + ({ \ + if (0) \ + _dev_printk(level, dev, fmt, ##__VA_ARGS__); \ + }) + /* * #defines for all the dev_ macros to prefix with whatever * possible use of #define dev_fmt(fmt) ... @@ -158,10 +168,7 @@ void _dev_info(const struct device *dev, const char *fmt, ...) dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #else #define dev_dbg(dev, fmt, ...) \ -({ \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -}) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif #ifdef CONFIG_PRINTK @@ -247,20 +254,14 @@ do { \ } while (0) #else #define dev_dbg_ratelimited(dev, fmt, ...) \ -do { \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -} while (0) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif #ifdef VERBOSE_DEBUG #define dev_vdbg dev_dbg #else #define dev_vdbg(dev, fmt, ...) \ -({ \ - if (0) \ - dev_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__); \ -}) + dev_no_printk(KERN_DEBUG, dev, dev_fmt(fmt), ##__VA_ARGS__) #endif /* -- cgit v1.2.3 From 0381e588949380704005dacdbef6e9a2920260df Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 28 Feb 2024 15:00:04 +0100 Subject: dyndbg: Use *no_printk() helpers When printk-indexing is enabled, each printk() or dev_printk() invocation emits a pi_entry structure. This is even true when the call is protected by an always-false check: while the actual code to print the message is optimized out by the compiler, the pi_entry structure is still emitted. Fix this by replacing "if (0) *printk(...)" constructs by calls to the corresponding *no_printk() helpers. Note that this has minimal impact, as most (all?) callers of dynamic_{pr,dev}_debug() are protected by checks for DYNAMIC_DEBUG anyway. Still, using the helpers serves as a good example to follow. Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Reviewed-by: Xiubo Li Reviewed-by: Chris Down Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/32e18ceb528b99d9147be9c1af578a1965e2bad9.1709127473.git.geert+renesas@glider.be Signed-off-by: Petr Mladek --- include/linux/dynamic_debug.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index 4fcbf4d4fd0a..ff44ec346162 100644 --- a/include/linux/dynamic_debug.h +++ b/include/linux/dynamic_debug.h @@ -305,9 +305,9 @@ void __dynamic_ibdev_dbg(struct _ddebug *descriptor, #define DYNAMIC_DEBUG_BRANCH(descriptor) false #define dynamic_pr_debug(fmt, ...) \ - do { if (0) printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); } while (0) + no_printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__) #define dynamic_dev_dbg(dev, fmt, ...) \ - do { if (0) dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); } while (0) + dev_no_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__) #define dynamic_hex_dump(prefix_str, prefix_type, rowsize, \ groupsize, buf, len, ascii) \ do { if (0) \ -- cgit v1.2.3 From b37cafacbf98ead69c2ecb220fb82b06aee916b9 Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Wed, 28 Feb 2024 15:00:05 +0100 Subject: ceph: Use no_printk() helper When printk-indexing is enabled, each printk() invocation emits a pi_entry structure. This is even true when the call is protected by an always-false check: while the actual code to print the message is optimized out by the compiler, the pi_entry structure is still emitted. Fix this by replacing "if (0) printk(...)" constructs by calls to the no_printk() helper. This reduces the size of an arm64 kernel with CONFIG_PRINTK_INDEX=y and CONFIG_CEPH_FS=y by ca. 4 KiB. Signed-off-by: Geert Uytterhoeven Reviewed-by: Andy Shevchenko Reviewed-by: Xiubo Li Reviewed-by: Chris Down Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/a21767eccb823435a7f18cdf115d7d572b4e945d.1709127473.git.geert+renesas@glider.be Signed-off-by: Petr Mladek --- include/linux/ceph/ceph_debug.h | 18 +++++++----------- 1 file changed, 7 insertions(+), 11 deletions(-) (limited to 'include/linux') diff --git a/include/linux/ceph/ceph_debug.h b/include/linux/ceph/ceph_debug.h index 11a92a946016..5f904591fa5f 100644 --- a/include/linux/ceph/ceph_debug.h +++ b/include/linux/ceph/ceph_debug.h @@ -27,17 +27,13 @@ ##__VA_ARGS__) # else /* faux printk call just to see any compiler warnings. */ -# define dout(fmt, ...) do { \ - if (0) \ - printk(KERN_DEBUG fmt, ##__VA_ARGS__); \ - } while (0) -# define doutc(client, fmt, ...) do { \ - if (0) \ - printk(KERN_DEBUG "[%pU %llu] " fmt, \ - &client->fsid, \ - client->monc.auth->global_id, \ - ##__VA_ARGS__); \ - } while (0) +# define dout(fmt, ...) \ + no_printk(KERN_DEBUG fmt, ##__VA_ARGS__) +# define doutc(client, fmt, ...) \ + no_printk(KERN_DEBUG "[%pU %llu] " fmt, \ + &client->fsid, \ + client->monc.auth->global_id, \ + ##__VA_ARGS__) # endif #else -- cgit v1.2.3 From b3e90f375b3c7ab85aef631ebb0ad8ce66cbf3fd Mon Sep 17 00:00:00 2001 From: Yoann Congal Date: Sun, 5 May 2024 10:03:42 +0200 Subject: printk: Change type of CONFIG_BASE_SMALL to bool CONFIG_BASE_SMALL is currently a type int but is only used as a boolean. So, change its type to bool and adapt all usages: CONFIG_BASE_SMALL == 0 becomes !IS_ENABLED(CONFIG_BASE_SMALL) and CONFIG_BASE_SMALL != 0 becomes IS_ENABLED(CONFIG_BASE_SMALL). Reviewed-by: Petr Mladek Reviewed-by: Greg Kroah-Hartman Reviewed-by: Masahiro Yamada Signed-off-by: Yoann Congal Link: https://lore.kernel.org/r/20240505080343.1471198-3-yoann.congal@smile.fr Signed-off-by: Petr Mladek --- include/linux/threads.h | 4 ++-- include/linux/udp.h | 2 +- include/linux/xarray.h | 2 +- 3 files changed, 4 insertions(+), 4 deletions(-) (limited to 'include/linux') diff --git a/include/linux/threads.h b/include/linux/threads.h index c34173e6c5f1..1674a471b0b4 100644 --- a/include/linux/threads.h +++ b/include/linux/threads.h @@ -25,13 +25,13 @@ /* * This controls the default maximum pid allocated to a process */ -#define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000) +#define PID_MAX_DEFAULT (IS_ENABLED(CONFIG_BASE_SMALL) ? 0x1000 : 0x8000) /* * A maximum of 4 million PIDs should be enough for a while. * [NOTE: PID/TIDs are limited to 2^30 ~= 1 billion, see FUTEX_TID_MASK.] */ -#define PID_MAX_LIMIT (CONFIG_BASE_SMALL ? PAGE_SIZE * 8 : \ +#define PID_MAX_LIMIT (IS_ENABLED(CONFIG_BASE_SMALL) ? PAGE_SIZE * 8 : \ (sizeof(long) > 4 ? 4 * 1024 * 1024 : PID_MAX_DEFAULT)) /* diff --git a/include/linux/udp.h b/include/linux/udp.h index 3748e82b627b..2d21cdb41ad8 100644 --- a/include/linux/udp.h +++ b/include/linux/udp.h @@ -24,7 +24,7 @@ static inline struct udphdr *udp_hdr(const struct sk_buff *skb) } #define UDP_HTABLE_SIZE_MIN_PERNET 128 -#define UDP_HTABLE_SIZE_MIN (CONFIG_BASE_SMALL ? 128 : 256) +#define UDP_HTABLE_SIZE_MIN (IS_ENABLED(CONFIG_BASE_SMALL) ? 128 : 256) #define UDP_HTABLE_SIZE_MAX 65536 static inline u32 udp_hashfn(const struct net *net, u32 num, u32 mask) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index cb571dfcf4b1..3f81ee5f9fb9 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -1141,7 +1141,7 @@ static inline void xa_release(struct xarray *xa, unsigned long index) * doubled the number of slots per node, we'd get only 3 nodes per 4kB page. */ #ifndef XA_CHUNK_SHIFT -#define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) +#define XA_CHUNK_SHIFT (IS_ENABLED(CONFIG_BASE_SMALL) ? 4 : 6) #endif #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) -- cgit v1.2.3 From e0550222e03bae3fd629641e246ef7f47803d795 Mon Sep 17 00:00:00 2001 From: Justin Stitt Date: Mon, 29 Apr 2024 23:06:54 +0000 Subject: printk: cleanup deprecated uses of strncpy/strcpy Cleanup some deprecated uses of strncpy() and strcpy() [1]. There doesn't seem to be any bugs with the current code but the readability of this code could benefit from a quick makeover while removing some deprecated stuff as a benefit. The most interesting replacement made in this patch involves concatenating "ttyS" with a digit-led user-supplied string. Instead of doing two distinct string copies with carefully managed offsets and lengths, let's use the more robust and self-explanatory scnprintf(). scnprintf will 1) respect the bounds of @buf, 2) null-terminate @buf, 3) do the concatenation. This allows us to drop the manual NUL-byte assignment. Also, since isdigit() is used about a dozen lines after the open-coded version we'll replace it for uniformity's sake. All the strcpy() --> strscpy() replacements are trivial as the source strings are literals and much smaller than the destination size. No behavioral change here. Use the new 2-argument version of strscpy() introduced in Commit e6584c3964f2f ("string: Allow 2-argument strscpy()"). However, to make this work fully (since the size must be known at compile time), also update the extern-qualified declaration to have the proper size information. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 [2] Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [3] Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt Reviewed-by: Petr Mladek Link: https://lore.kernel.org/r/20240429-strncpy-kernel-printk-printk-c-v1-1-4da7926d7b69@google.com [pmladek@suse.com: Removed obsolete brackets and added empty lines.] Signed-off-by: Petr Mladek --- include/linux/printk.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux') diff --git a/include/linux/printk.h b/include/linux/printk.h index 2fde40cc9677..dbbd202b1cb3 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -71,7 +71,7 @@ extern void console_verbose(void); /* strlen("ratelimit") + 1 */ #define DEVKMSG_STR_MAX_SIZE 10 -extern char devkmsg_log_str[]; +extern char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE]; struct ctl_table; extern int suppress_printk; -- cgit v1.2.3