jump label: Convert dynamic debug to use jump labels (52159d98) · Commits · e / devices / android_kernel_fairphone_FP4

include/linux/dynamic_debug.h

+21 −18

Original line number	Diff line number	Diff line
		#ifndef _DYNAMIC_DEBUG_H
		#define _DYNAMIC_DEBUG_H

		#include <linux/jump_label.h>

		/* dynamic_printk_enabled, and dynamic_printk_enabled2 are bitmasks in which
		* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
		* use independent hash functions, to reduce the chance of false positives.
		@@ -22,8 +24,6 @@ struct _ddebug {
		const char *function;
		const char *filename;
		const char *format;
		char primary_hash;
		char secondary_hash;
		unsigned int lineno:24;
		/*
		* The flags field controls the behaviour at the callsite.
		@@ -33,6 +33,7 @@ struct _ddebug {
		#define _DPRINTK_FLAGS_PRINT (1<<0) /* printk() a message using the format */
		#define _DPRINTK_FLAGS_DEFAULT 0
		unsigned int flags:8;
		char enabled;
		} __attribute__((aligned(8)));


		@@ -42,33 +43,35 @@ int ddebug_add_module(struct _ddebug *tab, unsigned int n,
		#if defined(CONFIG_DYNAMIC_DEBUG)
		extern int ddebug_remove_module(const char *mod_name);

		#define __dynamic_dbg_enabled(dd) ({ \
		int __ret = 0; \
		if (unlikely((dynamic_debug_enabled & (1LL << DEBUG_HASH)) && \
		(dynamic_debug_enabled2 & (1LL << DEBUG_HASH2)))) \
		if (unlikely(dd.flags)) \
		__ret = 1; \
		__ret; })

		#define dynamic_pr_debug(fmt, ...) do { \
		__label__ do_printk; \
		__label__ out; \
		static struct _ddebug descriptor \
		__used \
		__attribute__((section("__verbose"), aligned(8))) = \
		{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \
		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \
		if (__dynamic_dbg_enabled(descriptor)) \
		{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
		_DPRINTK_FLAGS_DEFAULT }; \
		JUMP_LABEL(&descriptor.enabled, do_printk); \
		goto out; \
		do_printk: \
		printk(KERN_DEBUG pr_fmt(fmt), ##__VA_ARGS__); \
		out: ; \
		} while (0)


		#define dynamic_dev_dbg(dev, fmt, ...) do { \
		__label__ do_printk; \
		__label__ out; \
		static struct _ddebug descriptor \
		__used \
		__attribute__((section("__verbose"), aligned(8))) = \
		{ KBUILD_MODNAME, __func__, __FILE__, fmt, DEBUG_HASH, \
		DEBUG_HASH2, __LINE__, _DPRINTK_FLAGS_DEFAULT }; \
		if (__dynamic_dbg_enabled(descriptor)) \
		{ KBUILD_MODNAME, __func__, __FILE__, fmt, __LINE__, \
		_DPRINTK_FLAGS_DEFAULT }; \
		JUMP_LABEL(&descriptor.enabled, do_printk); \
		goto out; \
		do_printk: \
		dev_printk(KERN_DEBUG, dev, fmt, ##__VA_ARGS__); \
		out: ; \
		} while (0)

		#else

lib/dynamic_debug.c

+3 −39

Original line number	Diff line number	Diff line
		@@ -26,19 +26,11 @@
		#include <linux/dynamic_debug.h>
		#include <linux/debugfs.h>
		#include <linux/slab.h>
		#include <linux/jump_label.h>

		extern struct _ddebug __start___verbose[];
		extern struct _ddebug __stop___verbose[];

		/* dynamic_debug_enabled, and dynamic_debug_enabled2 are bitmasks in which
		* bit n is set to 1 if any modname hashes into the bucket n, 0 otherwise. They
		* use independent hash functions, to reduce the chance of false positives.
		*/
		long long dynamic_debug_enabled;
		EXPORT_SYMBOL_GPL(dynamic_debug_enabled);
		long long dynamic_debug_enabled2;
		EXPORT_SYMBOL_GPL(dynamic_debug_enabled2);

		struct ddebug_table {
		struct list_head link;
		char *mod_name;
		@@ -87,26 +79,6 @@ static char ddebug_describe_flags(struct _ddebug dp, char *buf,
		return buf;
		}

		/*
		* must be called with ddebug_lock held
		*/

		static int disabled_hash(char hash, bool first_table)
		{
		struct ddebug_table *dt;
		char table_hash_value;

		list_for_each_entry(dt, &ddebug_tables, link) {
		if (first_table)
		table_hash_value = dt->ddebugs->primary_hash;
		else
		table_hash_value = dt->ddebugs->secondary_hash;
		if (dt->num_enabled && (hash == table_hash_value))
		return 0;
		}
		return 1;
		}

		/*
		* Search the tables for _ddebug's which match the given
		* `query' and apply the `flags' and `mask' to them. Tells
		@@ -170,17 +142,9 @@ static void ddebug_change(const struct ddebug_query *query,
		dt->num_enabled++;
		dp->flags = newflags;
		if (newflags) {
		dynamic_debug_enabled \|=
		(1LL << dp->primary_hash);
		dynamic_debug_enabled2 \|=
		(1LL << dp->secondary_hash);
		enable_jump_label(&dp->enabled);
		} else {
		if (disabled_hash(dp->primary_hash, true))
		dynamic_debug_enabled &=
		~(1LL << dp->primary_hash);
		if (disabled_hash(dp->secondary_hash, false))
		dynamic_debug_enabled2 &=
		~(1LL << dp->secondary_hash);
		disable_jump_label(&dp->enabled);
		}
		if (verbose)
		printk(KERN_INFO

scripts/Makefile.lib

+1 −10

Original line number	Diff line number	Diff line
		@@ -101,14 +101,6 @@ basename_flags = -D"KBUILD_BASENAME=KBUILD_STR($(call name-fix,$(basetarget)))"
		modname_flags = $(if $(filter 1,$(words $(modname))),\
		-D"KBUILD_MODNAME=KBUILD_STR($(call name-fix,$(modname)))")

		#hash values
		ifdef CONFIG_DYNAMIC_DEBUG
		debug_flags = -D"DEBUG_HASH=$(shell ./scripts/basic/hash djb2 $(@D)$(modname))"\
		-D"DEBUG_HASH2=$(shell ./scripts/basic/hash r5 $(@D)$(modname))"
		else
		debug_flags =
		endif

		orig_c_flags = $(KBUILD_CPPFLAGS) $(KBUILD_CFLAGS) $(KBUILD_SUBDIR_CCFLAGS) \
		$(ccflags-y) $(CFLAGS_$(basetarget).o)
		_c_flags = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(orig_c_flags))
		@@ -152,8 +144,7 @@ endif

		c_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
		$(__c_flags) $(modkern_cflags) \
		-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags) \
		$(debug_flags)
		-D"KBUILD_STR(s)=\#s" $(basename_flags) $(modname_flags)

		a_flags = -Wp,-MD,$(depfile) $(NOSTDINC_FLAGS) $(LINUXINCLUDE) \
		$(__a_flags) $(modkern_aflags)

scripts/basic/Makefile

+1 −1

Original line number	Diff line number	Diff line
		@@ -9,7 +9,7 @@
		# fixdep: Used to generate dependency information during build process
		# docproc: Used in Documentation/DocBook

		hostprogs-y := fixdep docproc hash
		hostprogs-y := fixdep docproc
		always := $(hostprogs-y)

		# fixdep is needed to compile other host programs

scripts/basic/hash.c

deleted100644 → 0

+0 −64

Original line number	Diff line number	Diff line
		/*
		* Copyright (C) 2008 Red Hat, Inc., Jason Baron <jbaron@redhat.com>
		*
		*/

		#include <stdio.h>
		#include <stdlib.h>
		#include <string.h>

		#define DYNAMIC_DEBUG_HASH_BITS 6

		static const char *program;

		static void usage(void)
		{
		printf("Usage: %s <djb2\|r5> <modname>\n", program);
		exit(1);
		}

		/* djb2 hashing algorithm by Dan Bernstein. From:
		* http://www.cse.yorku.ca/~oz/hash.html
		*/

		static unsigned int djb2_hash(char *str)
		{
		unsigned long hash = 5381;
		int c;

		c = *str;
		while (c) {
		hash = ((hash << 5) + hash) + c;
		c = *++str;
		}
		return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
		}

		static unsigned int r5_hash(char *str)
		{
		unsigned long hash = 0;
		int c;

		c = *str;
		while (c) {
		hash = (hash + (c << 4) + (c >> 4)) * 11;
		c = *++str;
		}
		return (unsigned int)(hash & ((1 << DYNAMIC_DEBUG_HASH_BITS) - 1));
		}

		int main(int argc, char *argv[])
		{
		program = argv[0];

		if (argc != 3)
		usage();
		if (!strcmp(argv[1], "djb2"))
		printf("%d\n", djb2_hash(argv[2]));
		else if (!strcmp(argv[1], "r5"))
		printf("%d\n", r5_hash(argv[2]));
		else
		usage();
		exit(0);
		}