Commit 7a555613 authored by Vladimir Kondratiev's avatar Vladimir Kondratiev Committed by Greg Kroah-Hartman
Browse files

dynamic_debug: dynamic hex dump 



Introduce print_hex_dump_debug() that can be dynamically controlled, similar to
pr_debug.

Also, make print_hex_dump_bytes() dynamically controlled

Implement only 'p' flag (_DPRINTK_FLAGS_PRINT) to keep it simple since hex dump prints
multiple lines and long prefix would impact readability.
To provide line/file etc. information, use pr_debug or similar
before/after print_hex_dump_debug()

Signed-off-by: default avatarVladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: default avatarJason Baron <jbaron@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f657fd21

Documentation/dynamic-debug-howto.txt

+13 −2
Original line number Diff line number Diff line
@@ -6,8 +6,16 @@ This document describes how to use the dynamic debug (dyndbg) feature. 


Dynamic debug is designed to allow you to dynamically enable/disable

kernel code to obtain additional kernel information.  Currently, if

CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() calls can

be dynamically enabled per-callsite.

CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_dbg() and

print_hex_dump_debug()/print_hex_dump_bytes() calls can be dynamically

enabled per-callsite.



If CONFIG_DYNAMIC_DEBUG is not set, print_hex_dump_debug() is just

shortcut for print_hex_dump(KERN_DEBUG).



For print_hex_dump_debug()/print_hex_dump_bytes(), format string is

its 'prefix_str' argument, if it is constant string; or "hexdump"

in case 'prefix_str' is build dynamically.



Dynamic debug has even more useful features:
@@ -202,6 +210,9 @@ The flags are: 
  t    Include thread ID in messages not generated from interrupt context

  _    No flags are set. (Or'd with others on input)



For print_hex_dump_debug() and print_hex_dump_bytes(), only 'p' flag

have meaning, other flags ignored.



For display, the flags are preceded by '='

(mnemonic: what the flags are currently equal to).

include/linux/dynamic_debug.h

+11 −0
Original line number Diff line number Diff line
@@ -95,6 +95,17 @@ do { \ 
				     ##__VA_ARGS__);		\

} while (0)



#define dynamic_hex_dump(prefix_str, prefix_type, rowsize,	\

			 groupsize, buf, len, ascii)		\

do {								\

	DEFINE_DYNAMIC_DEBUG_METADATA(descriptor,		\

		__builtin_constant_p(prefix_str) ? prefix_str : "hexdump");\

	if (unlikely(descriptor.flags & _DPRINTK_FLAGS_PRINT))	\

		print_hex_dump(KERN_DEBUG, prefix_str,		\

			       prefix_type, rowsize, groupsize,	\

			       buf, len, ascii);		\

} while (0)



#else



#include <linux/string.h>

include/linux/printk.h

+17 −0
Original line number Diff line number Diff line
@@ -321,8 +321,13 @@ extern void hex_dump_to_buffer(const void *buf, size_t len, 
extern void print_hex_dump(const char *level, const char *prefix_str,

			   int prefix_type, int rowsize, int groupsize,

			   const void *buf, size_t len, bool ascii);

#if defined(CONFIG_DYNAMIC_DEBUG)

#define print_hex_dump_bytes(prefix_str, prefix_type, buf, len)	\

	dynamic_hex_dump(prefix_str, prefix_type, 16, 1, buf, len, true)

#else

extern void print_hex_dump_bytes(const char *prefix_str, int prefix_type,

				 const void *buf, size_t len);

#endif /* defined(CONFIG_DYNAMIC_DEBUG) */

#else

static inline void print_hex_dump(const char *level, const char *prefix_str,

				  int prefix_type, int rowsize, int groupsize,
@@ -336,4 +341,16 @@ static inline void print_hex_dump_bytes(const char *prefix_str, int prefix_type, 


#endif



#if defined(CONFIG_DYNAMIC_DEBUG)

#define print_hex_dump_debug(prefix_str, prefix_type, rowsize,	\

			     groupsize, buf, len, ascii)	\

	dynamic_hex_dump(prefix_str, prefix_type, rowsize,	\

			 groupsize, buf, len, ascii)

#else

#define print_hex_dump_debug(prefix_str, prefix_type, rowsize,		\

			     groupsize, buf, len, ascii)		\

	print_hex_dump(KERN_DEBUG, prefix_str, prefix_type, rowsize,	\

		       groupsize, buf, len, ascii)

#endif /* defined(CONFIG_DYNAMIC_DEBUG) */



#endif

lib/hexdump.c

+3 −1
Original line number Diff line number Diff line
@@ -227,6 +227,7 @@ void print_hex_dump(const char *level, const char *prefix_str, int prefix_type, 
}

EXPORT_SYMBOL(print_hex_dump);



#if !defined(CONFIG_DYNAMIC_DEBUG)

/**

 * print_hex_dump_bytes - shorthand form of print_hex_dump() with default params

 * @prefix_str: string to prefix each line with;
@@ -246,4 +247,5 @@ void print_hex_dump_bytes(const char *prefix_str, int prefix_type, 
		       buf, len, true);

}

EXPORT_SYMBOL(print_hex_dump_bytes);

#endif
 
#endif /* !defined(CONFIG_DYNAMIC_DEBUG) */

#endif /* defined(CONFIG_PRINTK) */

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