Log hashing

Compile-time replacement of log strings by tokens (CONFIG_LOG_HASHED). More...

Macros
#define	NEW_LOG_VERSION   "0102"
	Version of the .log_strings format, major and minor on two digits each.
#define	LOG_STRINGS_SECTION_ADDRESS   0xC0000000
	Address the .log_strings section is linked at; tokens are offsets from it.
#define	PACKED_CORE_OFFSET   30
	Position of the core number in a message ID.
#define	PACKED_CORE_MASK   0x03
	Mask of the core number, 2 bits.
#define	PACKED_NUM_FMT_OFFSET   29
	Position of the number of format conversions in a token.
#define	PACKED_NUM_FMT_MASK   0x07
	Mask of the number of format conversions, 3 bits.
#define	PACKED_STR1FMT_OFFSET   26
	Position of the first string conversion index in a token.
#define	PACKED_STR1FMT_MASK   0x07
	Mask of the first string conversion index, 3 bits.
#define	PACKED_STR2FMT_OFFSET   23
	Position of the second string conversion index in a token.
#define	PACKED_STR2FMT_MASK   0x07
	Mask of the second string conversion index, 3 bits.
#define	PACKED_STRFMTS_OFFSET   23
	Position of both string conversion indices in a token.
#define	PACKED_STRFMTS_MASK   0x3f
	Mask of both string conversion indices, 6 bits.
#define	PACKED_LEVEL_OFFSET   20
	Position of the packed level in a token.
#define	PACKED_LEVEL_MASK   0x07
	Mask of the packed level, 3 bits.
#define	PACKED_HASH_OFFSET   0
	Position of the string offset in a token.
#define	PACKED_HASH_MASK   0x7FFFF
	Mask of the string offset, 19 bits.
#define	MSGID_STR_AND_HASH_MASK    ((PACKED_STRFMTS_MASK << PACKED_STRFMTS_OFFSET) | (PACKED_HASH_MASK << PACKED_HASH_OFFSET))
	Mask of the string indices and string offset of a message ID.
#define	MSGID_CORE_AND_HASH_MASK    ((PACKED_CORE_MASK << PACKED_CORE_OFFSET) | (PACKED_HASH_MASK << PACKED_HASH_OFFSET))
	Mask of the core number and string offset of a message ID.
#define	STRINGIFY_NX(a)   #a
	Turn the argument into a string literal without expanding it.
#define	STRINGIFY(a)   STRINGIFY_NX(a)
	Turn the expansion of the argument into a string literal.

Detailed Description

Compile-time replacement of log strings by tokens (CONFIG_LOG_HASHED).

Each PBL_LOG call site places "file:line:level:color:format" in the .log_strings section, which is linked at LOG_STRINGS_SECTION_ADDRESS, outside the firmware image, and logs a token instead of the string. The host turns tokens back into messages with the dictionary extracted from the ELF file.

Token layout:

• bits 31-29: number of format conversions, 0 to 7;
• bits 28-23: 1-based indices of up to two %s conversions, 3 bits each, 0 for none;
• bits 22-20: level, 0 to 5 for LOG_LEVEL_ALWAYS to LOG_LEVEL_DEBUG_VERBOSE;
• bit 19: reserved;
• bits 18-0: offset of the string in .log_strings (512 KiB).

The .log_strings section holds:

• .log_string.header: "NL\<major\>\<minor\>:\<offset mask\>=\<token list\>", the format version and description of the entries;
• .log_core_number: "CORE\<number\>", the core the strings belong to;
• .log_string: the strings of every call site, plus "MODULE:\<file\>:\<module\>" entries emitted by PBL_LOG_MODULE_DEFINE() and PBL_LOG_MODULE_DECLARE() that map files to log modules and are never referenced by a token.

Limitations: at most 7 conversions per message, at most 2 of them %s, without flags or width; no %%; only arguments of 32 bits or less (see SPLIT_64_BIT_ARG()). Formats breaking them are not detected at build time. The code must be built with -Os, or the token computation is not folded.

Macro Definition Documentation

LOG_STRINGS_SECTION_ADDRESS

#define LOG_STRINGS_SECTION_ADDRESS   0xC0000000

Address the .log_strings section is linked at; tokens are offsets from it.

MSGID_CORE_AND_HASH_MASK

#define MSGID_CORE_AND_HASH_MASK    ((PACKED_CORE_MASK << PACKED_CORE_OFFSET) | (PACKED_HASH_MASK << PACKED_HASH_OFFSET))

Mask of the core number and string offset of a message ID.

MSGID_STR_AND_HASH_MASK

#define MSGID_STR_AND_HASH_MASK    ((PACKED_STRFMTS_MASK << PACKED_STRFMTS_OFFSET) | (PACKED_HASH_MASK << PACKED_HASH_OFFSET))

Mask of the string indices and string offset of a message ID.

NEW_LOG_VERSION

#define NEW_LOG_VERSION   "0102"

Version of the .log_strings format, major and minor on two digits each.

PACKED_CORE_MASK

#define PACKED_CORE_MASK   0x03

Mask of the core number, 2 bits.

PACKED_CORE_OFFSET

#define PACKED_CORE_OFFSET   30

Position of the core number in a message ID.

PACKED_HASH_MASK

#define PACKED_HASH_MASK   0x7FFFF

Mask of the string offset, 19 bits.

PACKED_HASH_OFFSET

#define PACKED_HASH_OFFSET   0

Position of the string offset in a token.

PACKED_LEVEL_MASK

#define PACKED_LEVEL_MASK   0x07

Mask of the packed level, 3 bits.

PACKED_LEVEL_OFFSET

#define PACKED_LEVEL_OFFSET   20

Position of the packed level in a token.

PACKED_NUM_FMT_MASK

#define PACKED_NUM_FMT_MASK   0x07

Mask of the number of format conversions, 3 bits.

PACKED_NUM_FMT_OFFSET

#define PACKED_NUM_FMT_OFFSET   29

Position of the number of format conversions in a token.

PACKED_STR1FMT_MASK

#define PACKED_STR1FMT_MASK   0x07

Mask of the first string conversion index, 3 bits.

PACKED_STR1FMT_OFFSET

#define PACKED_STR1FMT_OFFSET   26

Position of the first string conversion index in a token.

PACKED_STR2FMT_MASK

#define PACKED_STR2FMT_MASK   0x07

Mask of the second string conversion index, 3 bits.

PACKED_STR2FMT_OFFSET

#define PACKED_STR2FMT_OFFSET   23

Position of the second string conversion index in a token.

PACKED_STRFMTS_MASK

#define PACKED_STRFMTS_MASK   0x3f

Mask of both string conversion indices, 6 bits.

PACKED_STRFMTS_OFFSET

#define PACKED_STRFMTS_OFFSET   23

Position of both string conversion indices in a token.

STRINGIFY

#define STRINGIFY

(

a

)

STRINGIFY_NX(a)

Turn the expansion of the argument into a string literal.

Parameters

a

Argument.

STRINGIFY_NX

#define STRINGIFY_NX

(

a

)

#a

Turn the argument into a string literal without expanding it.

Parameters

a

Argument.