Attachment 314335 Details for Bug 459141 – patch for mcount record change to nop on boot up

[patch] patch for mcount record change to nop on boot up

ftrace-mcount-record-big.patch (text/plain), 24.84 KB, created by Steven Rostedt on 2008-08-14 17:43:21 UTC

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Creator: Steven Rostedt

Created: 2008-08-14 17:43:21 UTC

Size: 24.84 KB

patch

obsolete

>Index: linux-2.6.24.7.noarch/include/asm-generic/vmlinux.lds.h
>===================================================================
>--- linux-2.6.24.7.noarch.orig/include/asm-generic/vmlinux.lds.h
>+++ linux-2.6.24.7.noarch/include/asm-generic/vmlinux.lds.h
>@@ -9,6 +9,14 @@
> /* Align . to a 8 byte boundary equals to maximum function alignment. */
> #define ALIGN_FUNCTION()  . = ALIGN(8)
> 
>+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
>+#define MCOUNT_REC()	VMLINUX_SYMBOL(__start_mcount_loc) = .; \
>+			*(__mcount_loc)				\
>+			VMLINUX_SYMBOL(__stop_mcount_loc) = .;
>+#else
>+#define MCOUNT_REC()
>+#endif
>+
> /* .data section */
> #define DATA_DATA							\
> 	*(.data)							\
>Index: linux-2.6.24.7.noarch/scripts/Makefile.build
>===================================================================
>--- linux-2.6.24.7.noarch.orig/scripts/Makefile.build
>+++ linux-2.6.24.7.noarch/scripts/Makefile.build
>@@ -192,10 +192,16 @@ cmd_modversions =							\
> 	fi;
> endif
> 
>+ifdef CONFIG_FTRACE_MCOUNT_RECORD
>+cmd_record_mcount = scripts/recordmcount.pl "$(ARCH)" \
>+	"$(OBJDUMP)" "$(OBJCOPY)" "$(CC)" "$(LD)" "$(NM)" "$(RM)" "$(MV)" "$(@)";
>+endif
>+
> define rule_cc_o_c
> 	$(call echo-cmd,checksrc) $(cmd_checksrc)			  \
> 	$(call echo-cmd,cc_o_c) $(cmd_cc_o_c);				  \
> 	$(cmd_modversions)						  \
>+	$(cmd_record_mcount)						  \
> 	scripts/basic/fixdep $(depfile) $@ '$(call make-cmd,cc_o_c)' >    \
> 	                                              $(dot-target).tmp;  \
> 	rm -f $(depfile);						  \
>Index: linux-2.6.24.7.noarch/scripts/recordmcount.pl
>===================================================================
>--- /dev/null
>+++ linux-2.6.24.7.noarch/scripts/recordmcount.pl
>@@ -0,0 +1,280 @@
>+#!/usr/bin/perl -w
>+# (c) 2008, Steven Rostedt <srostedt@redhat.com>
>+# Licensed under the terms of the GNU GPL License version 2
>+#
>+# recordmcount.pl - makes a section called __mcount_loc that holds
>+#                   all the offsets to the calls to mcount.
>+#
>+#
>+# What we want to end up with is a section in vmlinux called
>+# __mcount_loc that contains a list of pointers to all the
>+# call sites in the kernel that call mcount. Later on boot up, the kernel
>+# will read this list, save the locations and turn them into nops.
>+# When tracing or profiling is later enabled, these locations will then
>+# be converted back to pointers to some function.
>+#
>+# This is no easy feat. This script is called just after the original
>+# object is compiled and before it is linked.
>+#
>+# The references to the call sites are offsets from the section of text
>+# that the call site is in. Hence, all functions in a section that
>+# has a call site to mcount, will have the offset from the beginning of
>+# the section and not the beginning of the function.
>+#
>+# The trick is to find a way to record the beginning of the section.
>+# The way we do this is to look at the first function in the section
>+# which will also be the location of that section after final link.
>+# e.g.
>+#
>+#  .section ".text.sched"
>+#  .globl my_func
>+#  my_func:
>+#        [...]
>+#        call mcount  (offset: 0x5)
>+#        [...]
>+#        ret
>+#  other_func:
>+#        [...]
>+#        call mcount (offset: 0x1b)
>+#        [...]
>+#
>+# Both relocation offsets for the mcounts in the above example will be
>+# offset from .text.sched. If we make another file called tmp.s with:
>+#
>+#  .section __mcount_loc
>+#  .quad  my_func + 0x5
>+#  .quad  my_func + 0x1b
>+#
>+# We can then compile this tmp.s into tmp.o, and link it to the original
>+# object.
>+#
>+# But this gets hard if my_func is not globl (a static function).
>+# In such a case we have:
>+#
>+#  .section ".text.sched"
>+#  my_func:
>+#        [...]
>+#        call mcount  (offset: 0x5)
>+#        [...]
>+#        ret
>+#  .globl my_func
>+#  other_func:
>+#        [...]
>+#        call mcount (offset: 0x1b)
>+#        [...]
>+#
>+# If we make the tmp.s the same as above, when we link together with
>+# the original object, we will end up with two symbols for my_func:
>+# one local, one global.  After final compile, we will end up with
>+# an undefined reference to my_func.
>+#
>+# Since local objects can reference local variables, we need to find
>+# a way to make tmp.o reference the local objects of the original object
>+# file after it is linked together. To do this, we convert the my_func
>+# into a global symbol before linking tmp.o. Then after we link tmp.o
>+# we will only have a single symbol for my_func that is global.
>+# We can convert my_func back into a local symbol and we are done.
>+#
>+# Here are the steps we take:
>+#
>+# 1) Record all the local symbols by using 'nm'
>+# 2) Use objdump to find all the call site offsets and sections for
>+#    mcount.
>+# 3) Compile the list into its own object.
>+# 4) Do we have to deal with local functions? If not, go to step 8.
>+# 5) Make an object that converts these local functions to global symbols
>+#    with objcopy.
>+# 6) Link together this new object with the list object.
>+# 7) Convert the local functions back to local symbols and rename
>+#    the result as the original object.
>+#    End.
>+# 8) Link the object with the list object.
>+# 9) Move the result back to the original object.
>+#    End.
>+#
>+
>+use strict;
>+
>+my $P = $0;
>+$P =~ s@.*/@@g;
>+
>+my $V = '0.1';
>+
>+if ($#ARGV < 6) {
>+	print "usage: $P arch objdump objcopy cc ld nm rm mv inputfile\n";
>+	print "version: $V\n";
>+	exit(1);
>+}
>+
>+my ($arch, $objdump, $objcopy, $cc, $ld, $nm, $rm, $mv, $inputfile) = @ARGV;
>+
>+$objdump = "objdump" if ((length $objdump) == 0);
>+$objcopy = "objcopy" if ((length $objcopy) == 0);
>+$cc = "gcc" if ((length $cc) == 0);
>+$ld = "ld" if ((length $ld) == 0);
>+$nm = "nm" if ((length $nm) == 0);
>+$rm = "rm" if ((length $rm) == 0);
>+$mv = "mv" if ((length $mv) == 0);
>+
>+#print STDERR "running: $P '$arch' '$objdump' '$objcopy' '$cc' '$ld' " .
>+#    "'$nm' '$rm' '$mv' '$inputfile'\n";
>+
>+my %locals;
>+my %convert;
>+
>+my $type;
>+my $section_regex;	# Find the start of a section
>+my $function_regex;	# Find the name of a function (return func name)
>+my $mcount_regex;	# Find the call site to mcount (return offset)
>+
>+if ($arch eq "x86_64") {
>+    $section_regex = "Disassembly of section";
>+    $function_regex = "<(.*?)>:";
>+    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
>+    $type = ".quad";
>+} elsif ($arch eq "i386") {
>+    $section_regex = "Disassembly of section";
>+    $function_regex = "<(.*?)>:";
>+    $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
>+    $type = ".long";
>+} else {
>+    die "Arch $arch is not supported with CONFIG_FTRACE_MCOUNT_RECORD";
>+}
>+
>+my $text_found = 0;
>+my $read_function = 0;
>+my $opened = 0;
>+my $text = "";
>+my $mcount_section = "__mcount_loc";
>+
>+my $dirname;
>+my $filename;
>+my $prefix;
>+my $ext;
>+
>+if ($inputfile =~ m,^(.*)/([^/]*)$,) {
>+    $dirname = $1;
>+    $filename = $2;
>+} else {
>+    $dirname = ".";
>+    $filename = $inputfile;
>+}
>+
>+if ($filename =~ m,^(.*)(\.\S),) {
>+    $prefix = $1;
>+    $ext = $2;
>+} else {
>+    $prefix = $filename;
>+    $ext = "";
>+}
>+
>+my $mcount_s = $dirname . "/.tmp_mc_" . $prefix . ".s";
>+my $mcount_o = $dirname . "/.tmp_mc_" . $prefix . ".o";
>+
>+#
>+# Step 1: find all the local symbols (static functions).
>+#
>+open (IN, "$nm $inputfile|") || die "error running $nm";
>+while (<IN>) {
>+    if (/^[0-9a-fA-F]+\s+t\s+(\S+)/) {
>+	$locals{$1} = 1;
>+    }
>+}
>+close(IN);
>+
>+#
>+# Step 2: find the sections and mcount call sites
>+#
>+open(IN, "$objdump -dr $inputfile|") || die "error running $objdump";
>+
>+while (<IN>) {
>+    # is it a section?
>+    if (/$section_regex/) {
>+	$read_function = 1;
>+	$text_found = 0;
>+    # section found, now is this a start of a function?
>+    } elsif ($read_function && /$function_regex/) {
>+	$read_function = 0;
>+	$text_found = 1;
>+	$text = $1;
>+	# is this function static? If so, note this fact.
>+	if (defined $locals{$text}) {
>+	    $convert{$text} = 1;
>+	}
>+    # is this a call site to mcount? If so, print the offset from the section
>+    } elsif ($text_found && /$mcount_regex/) {
>+	if (!$opened) {
>+	    open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
>+	    $opened = 1;
>+	    print FILE "\t.section $mcount_section,\"a\",\@progbits\n";
>+	}
>+	print FILE "\t$type $text + 0x$1\n";
>+    }
>+}
>+
>+# If we did not find any mcount callers, we are done (do nothing).
>+if (!$opened) {
>+    exit(0);
>+}
>+
>+close(FILE);
>+
>+#
>+# Step 3: Compile the file that holds the list of call sites to mcount.
>+#
>+`$cc -o $mcount_o -c $mcount_s`;
>+
>+my @converts = keys %convert;
>+
>+#
>+# Step 4: Do we have sections that started with local functions?
>+#
>+if ($#converts >= 0) {
>+    my $globallist = "";
>+    my $locallist = "";
>+
>+    foreach my $con (@converts) {
>+	$globallist .= " --globalize-symbol $con";
>+	$locallist .= " --localize-symbol $con";
>+    }
>+
>+    my $globalobj = $dirname . "/.tmp_gl_" . $filename;
>+    my $globalmix = $dirname . "/.tmp_mx_" . $filename;
>+
>+    #
>+    # Step 5: set up each local function as a global
>+    #
>+    `$objcopy $globallist $inputfile $globalobj`;
>+
>+    #
>+    # Step 6: Link the global version to our list.
>+    #
>+    `$ld -r $globalobj $mcount_o -o $globalmix`;
>+
>+    #
>+    # Step 7: Convert the local functions back into local symbols
>+    #
>+    `$objcopy $locallist $globalmix $inputfile`;
>+
>+    # Remove the temp files
>+    `$rm $globalobj $globalmix`;
>+
>+} else {
>+
>+    my $mix = $dirname . "/.tmp_mx_" . $filename;
>+
>+    #
>+    # Step 8: Link the object with our list of call sites object.
>+    #
>+    `$ld -r $inputfile $mcount_o -o $mix`;
>+
>+    #
>+    # Step 9: Move the result back to the original object.
>+    #
>+    `$mv $mix $inputfile`;
>+}
>+
>+# Clean up the temp files
>+`$rm $mcount_o $mcount_s`;
>+
>+exit(0);
>Index: linux-2.6.24.7.noarch/kernel/trace/Kconfig
>===================================================================
>--- linux-2.6.24.7.noarch.orig/kernel/trace/Kconfig
>+++ linux-2.6.24.7.noarch/kernel/trace/Kconfig
>@@ -7,6 +7,9 @@ config HAVE_FTRACE
> config HAVE_DYNAMIC_FTRACE
> 	bool
> 
>+config HAVE_FTRACE_MCOUNT_RECORD
>+	bool
>+
> config TRACER_MAX_TRACE
> 	bool
> 
>@@ -122,6 +125,11 @@ config DYNAMIC_FTRACE
> 	 were made. If so, it runs stop_machine (stops all CPUS)
> 	 and modifies the code to jump over the call to ftrace.
> 
>+config FTRACE_MCOUNT_RECORD
>+	def_bool y
>+	depends on DYNAMIC_FTRACE
>+	depends on HAVE_FTRACE_MCOUNT_RECORD
>+
> config FTRACE_SELFTEST
> 	bool
> 
>Index: linux-2.6.24.7.noarch/include/linux/ftrace.h
>===================================================================
>--- linux-2.6.24.7.noarch.orig/include/linux/ftrace.h
>+++ linux-2.6.24.7.noarch/include/linux/ftrace.h
>@@ -203,4 +203,30 @@ static inline void ftrace_event_program_
> # define ftrace_event_program_event(p, d)	do { } while (0)
> #endif /* CONFIG_TRACE_EVENTS */
> 
>+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
>+extern void ftrace_init(void);
>+extern void ftrace_init_module(unsigned long *start, unsigned long *end);
>+#else
>+static inline void ftrace_init(void) { }
>+static inline void
>+ftrace_init_module(unsigned long *start, unsigned long *end) { }
>+#endif
>+
>+/* Upstream has include/asm-x86/ftrace.h, but we'll hack this for now */
>+#ifdef CONFIG_X86
>+static inline unsigned long ftrace_call_adjust(unsigned long addr)
>+{
>+	/*
>+	 * call mcount is "e8 <4 byte offset>"
>+	 * The addr points to the 4 byte offset and the caller of this
>+	 * function wants the pointer to e8. Simply subtract one.
>+	 */
>+	return addr - 1;
>+}
>+#else
>+static inline unsigned long ftrace_call_adjust(unsigned long addr)
>+{
>+	return addr;
>+}
>+#endif
> #endif /* _LINUX_FTRACE_H */
>Index: linux-2.6.24.7.noarch/init/main.c
>===================================================================
>--- linux-2.6.24.7.noarch.orig/init/main.c
>+++ linux-2.6.24.7.noarch/init/main.c
>@@ -60,6 +60,7 @@
> #include <linux/kthread.h>
> #include <linux/sched.h>
> #include <linux/ftrace.h>
>+#include <linux/ftrace.h>
> 
> #include <asm/io.h>
> #include <asm/bugs.h>
>@@ -658,6 +659,8 @@ asmlinkage void __init start_kernel(void
> 
> 	acpi_early_init(); /* before LAPIC and SMP init */
> 
>+	ftrace_init();
>+
> #ifdef CONFIG_PREEMPT_RT
> 	WARN_ON(irqs_disabled());
> #endif
>@@ -878,7 +881,7 @@ static int __init kernel_init(void * unu
> 	WARN_ON(irqs_disabled());
> #endif
> 
>-#define DEBUG_COUNT (defined(CONFIG_DEBUG_RT_MUTEXES) + defined(CONFIG_IRQSOFF_TRACER) + defined(CONFIG_PREEMPT_TRACER) + defined(CONFIG_FTRACE) + defined(CONFIG_WAKEUP_LATENCY_HIST) + defined(CONFIG_DEBUG_SLAB) + defined(CONFIG_DEBUG_PAGEALLOC) + defined(CONFIG_LOCKDEP))
>+#define DEBUG_COUNT (defined(CONFIG_DEBUG_RT_MUTEXES) + defined(CONFIG_IRQSOFF_TRACER) + defined(CONFIG_PREEMPT_TRACER) + (defined(CONFIG_FTRACE) - defined(CONFIG_FTRACE_MCOUNT_RECORD)) + defined(CONFIG_WAKEUP_LATENCY_HIST) + defined(CONFIG_DEBUG_SLAB) + defined(CONFIG_DEBUG_PAGEALLOC) + defined(CONFIG_LOCKDEP))
> 
> #if DEBUG_COUNT > 0
> 	printk(KERN_ERR "*****************************************************************************\n");
>@@ -898,7 +901,7 @@ static int __init kernel_init(void * unu
> #ifdef CONFIG_PREEMPT_TRACER
> 	printk(KERN_ERR "*        CONFIG_PREEMPT_TRACER                                              *\n");
> #endif
>-#ifdef CONFIG_FTRACE
>+#if defined(CONFIG_FTRACE) - defined(CONFIG_FTRACE_MCOUNT_RECORD)
> 	printk(KERN_ERR "*        CONFIG_FTRACE                                                      *\n");
> #endif
> #ifdef CONFIG_WAKEUP_LATENCY_HIST
>Index: linux-2.6.24.7.noarch/kernel/trace/ftrace.c
>===================================================================
>--- linux-2.6.24.7.noarch.orig/kernel/trace/ftrace.c
>+++ linux-2.6.24.7.noarch/kernel/trace/ftrace.c
>@@ -324,13 +324,6 @@ ftrace_record_ip(unsigned long ip)
> 	if (ftrace_ip_in_hash(ip, key))
> 		goto out_unlock;
> 
>-	/*
>-	 * There's a slight race that the ftraced will update the
>-	 * hash and reset here. If it is already converted, skip it.
>-	 */
>-	if (ftrace_ip_converted(ip))
>-		goto out_unlock;
>-
> 	node = ftrace_alloc_dyn_node(ip);
> 	if (!node)
> 		goto out_unlock;
>@@ -697,47 +690,7 @@ static int ftrace_update_code(void)
> 	return 1;
> }
> 
>-static int ftraced(void *ignore)
>-{
>-	unsigned long usecs;
>-
>-	while (!kthread_should_stop()) {
>-
>-		set_current_state(TASK_INTERRUPTIBLE);
>-
>-		/* check once a second */
>-		schedule_timeout(HZ);
>-
>-		if (unlikely(ftrace_disabled))
>-			continue;
>-
>-		mutex_lock(&ftrace_sysctl_lock);
>-		mutex_lock(&ftraced_lock);
>-		if (!ftraced_suspend && !ftraced_stop &&
>-		    ftrace_update_code()) {
>-			usecs = nsecs_to_usecs(ftrace_update_time);
>-			if (ftrace_update_tot_cnt > 100000) {
>-				ftrace_update_tot_cnt = 0;
>-				pr_info("hm, dftrace overflow: %lu change%s"
>-					" (%lu total) in %lu usec%s\n",
>-					ftrace_update_cnt,
>-					ftrace_update_cnt != 1 ? "s" : "",
>-					ftrace_update_tot_cnt,
>-					usecs, usecs != 1 ? "s" : "");
>-				ftrace_disabled = 1;
>-				WARN_ON_ONCE(1);
>-			}
>-		}
>-		mutex_unlock(&ftraced_lock);
>-		mutex_unlock(&ftrace_sysctl_lock);
>-
>-		ftrace_shutdown_replenish();
>-	}
>-	__set_current_state(TASK_RUNNING);
>-	return 0;
>-}
>-
>-static int __init ftrace_dyn_table_alloc(void)
>+static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
> {
> 	struct ftrace_page *pg;
> 	int cnt;
>@@ -764,7 +717,9 @@ static int __init ftrace_dyn_table_alloc
> 
> 	pg = ftrace_pages = ftrace_pages_start;
> 
>-	cnt = NR_TO_INIT / ENTRIES_PER_PAGE;
>+	cnt = num_to_init / ENTRIES_PER_PAGE;
>+	pr_info("ftrace: allocating %ld hash entries in %d pages\n",
>+		num_to_init, cnt);
> 
> 	for (i = 0; i < cnt; i++) {
> 		pg->next = (void *)get_zeroed_page(GFP_KERNEL);
>@@ -1423,6 +1378,109 @@ static __init int ftrace_init_debugfs(vo
> 
> fs_initcall(ftrace_init_debugfs);
> 
>+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
>+static int ftrace_convert_nops(unsigned long *start,
>+			       unsigned long *end)
>+{
>+	unsigned long *p;
>+	unsigned long addr;
>+	unsigned long flags;
>+
>+	p = start;
>+	while (p < end) {
>+		addr = ftrace_call_adjust(*p++);
>+		ftrace_record_ip(addr);
>+		ftrace_shutdown_replenish();
>+	}
>+
>+	/* p is ignored */
>+	local_irq_save(flags);
>+	__ftrace_update_code(p);
>+	local_irq_restore(flags);
>+
>+	return 0;
>+}
>+
>+void ftrace_init_module(unsigned long *start, unsigned long *end)
>+{
>+	ftrace_convert_nops(start, end);
>+}
>+
>+extern unsigned long __start_mcount_loc[];
>+extern unsigned long __stop_mcount_loc[];
>+
>+void __init ftrace_init(void)
>+{
>+	unsigned long count, addr, flags;
>+	int ret;
>+
>+	/* Keep the ftrace pointer to the stub */
>+	addr = (unsigned long)ftrace_stub;
>+
>+	local_irq_save(flags);
>+	ftrace_dyn_arch_init(&addr);
>+	local_irq_restore(flags);
>+
>+	/* ftrace_dyn_arch_init places the return code in addr */
>+	if (addr)
>+		goto failed;
>+
>+	count = __stop_mcount_loc - __start_mcount_loc;
>+
>+	ret = ftrace_dyn_table_alloc(count);
>+	if (ret)
>+		goto failed;
>+
>+	last_ftrace_enabled = ftrace_enabled = 1;
>+
>+	ret = ftrace_convert_nops(__start_mcount_loc,
>+				  __stop_mcount_loc);
>+
>+	return;
>+ failed:
>+	ftrace_disabled = 1;
>+}
>+#else /* CONFIG_FTRACE_MCOUNT_RECORD */
>+static int ftraced(void *ignore)
>+{
>+	unsigned long usecs;
>+
>+	while (!kthread_should_stop()) {
>+
>+		set_current_state(TASK_INTERRUPTIBLE);
>+
>+		/* check once a second */
>+		schedule_timeout(HZ);
>+
>+		if (unlikely(ftrace_disabled))
>+			continue;
>+
>+		mutex_lock(&ftrace_sysctl_lock);
>+		mutex_lock(&ftraced_lock);
>+		if (!ftraced_suspend && !ftraced_stop &&
>+		    ftrace_update_code()) {
>+			usecs = nsecs_to_usecs(ftrace_update_time);
>+			if (ftrace_update_tot_cnt > 100000) {
>+				ftrace_update_tot_cnt = 0;
>+				pr_info("hm, dftrace overflow: %lu change%s"
>+					" (%lu total) in %lu usec%s\n",
>+					ftrace_update_cnt,
>+					ftrace_update_cnt != 1 ? "s" : "",
>+					ftrace_update_tot_cnt,
>+					usecs, usecs != 1 ? "s" : "");
>+				ftrace_disabled = 1;
>+				WARN_ON_ONCE(1);
>+			}
>+		}
>+		mutex_unlock(&ftraced_lock);
>+		mutex_unlock(&ftrace_sysctl_lock);
>+
>+		ftrace_shutdown_replenish();
>+	}
>+	__set_current_state(TASK_RUNNING);
>+	return 0;
>+}
>+
> static int __init ftrace_dynamic_init(void)
> {
> 	struct task_struct *p;
>@@ -1439,7 +1497,7 @@ static int __init ftrace_dynamic_init(vo
> 		goto failed;
> 	}
> 
>-	ret = ftrace_dyn_table_alloc();
>+	ret = ftrace_dyn_table_alloc(NR_TO_INIT);
> 	if (ret)
> 		goto failed;
> 
>@@ -1460,6 +1518,8 @@ static int __init ftrace_dynamic_init(vo
> }
> 
> core_initcall(ftrace_dynamic_init);
>+#endif /* CONFIG_FTRACE_MCOUNT_RECORD */
>+
> #else
> # define ftrace_startup()		do { } while (0)
> # define ftrace_shutdown()		do { } while (0)
>Index: linux-2.6.24.7.noarch/kernel/module.c
>===================================================================
>--- linux-2.6.24.7.noarch.orig/kernel/module.c
>+++ linux-2.6.24.7.noarch/kernel/module.c
>@@ -49,6 +49,7 @@
> #include <linux/license.h>
> #include <asm/sections.h>
> #include <linux/marker.h>
>+#include <linux/ftrace.h>
> 
> extern int module_sysfs_initialized;
> 
>@@ -1682,6 +1683,7 @@ static struct module *load_module(void _
> 	unsigned int immediatecondendindex;
> 	unsigned int markersindex;
> 	unsigned int markersstringsindex;
>+	unsigned int mcountindex;
> 	struct module *mod;
> 	long err = 0;
> 	void *percpu = NULL, *ptr = NULL; /* Stops spurious gcc warning */
>@@ -1965,6 +1967,9 @@ static struct module *load_module(void _
>  	markersstringsindex = find_sec(hdr, sechdrs, secstrings,
> 					"__markers_strings");
> 
>+	mcountindex = find_sec(hdr, sechdrs, secstrings,
>+			       "__mcount_loc");
>+
> 	/* Now do relocations. */
> 	for (i = 1; i < hdr->e_shnum; i++) {
> 		const char *strtab = (char *)sechdrs[strindex].sh_addr;
>@@ -2020,6 +2025,12 @@ static struct module *load_module(void _
> 			mod->immediate + mod->num_immediate);
> #endif
> 	}
>+
>+	if (mcountindex) {
>+		void *mseg = (void *)sechdrs[mcountindex].sh_addr;
>+		ftrace_init_module(mseg, mseg + sechdrs[mcountindex].sh_size);
>+	}
>+
> 	err = module_finalize(hdr, sechdrs, mod);
> 	if (err < 0)
> 		goto cleanup;
>Index: linux-2.6.24.7.noarch/include/linux/kernel.h
>===================================================================
>--- linux-2.6.24.7.noarch.orig/include/linux/kernel.h
>+++ linux-2.6.24.7.noarch/include/linux/kernel.h
>@@ -439,4 +439,9 @@ struct sysinfo {
> #define NUMA_BUILD 0
> #endif
> 
>+/* Rebuild everything on CONFIG_FTRACE_MCOUNT_RECORD */
>+#ifdef CONFIG_FTRACE_MCOUNT_RECORD
>+# define REBUILD_DUE_TO_FTRACE_MCOUNT_RECORD
>+#endif
>+
> #endif
>Index: linux-2.6.24.7.noarch/arch/x86/Kconfig
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/Kconfig
>+++ linux-2.6.24.7.noarch/arch/x86/Kconfig
>@@ -19,6 +19,7 @@ config X86_64
> config X86
> 	bool
> 	default y
>+	select HAVE_FTRACE_MCOUNT_RECORD
> 	select HAVE_DYNAMIC_FTRACE
> 	select HAVE_FTRACE
> 
>Index: linux-2.6.24.7.noarch/arch/x86/kernel/ftrace.c
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/kernel/ftrace.c
>+++ linux-2.6.24.7.noarch/arch/x86/kernel/ftrace.c
>@@ -17,6 +17,7 @@
> #include <linux/list.h>
> 
> #include <asm/alternative.h>
>+#include <asm/processor.h>
> #include <asm/asm.h>
> 
> #define CALL_BACK		5
>@@ -32,16 +33,6 @@ union ftrace_code_union {
> 	} __attribute__((packed));
> };
> 
>-notrace int ftrace_ip_converted(unsigned long ip)
>-{
>-	unsigned long save;
>-
>-	ip -= CALL_BACK;
>-	save = *(long *)ip;
>-
>-	return save == *ftrace_nop;
>-}
>-
> static int notrace ftrace_calc_offset(long ip, long addr)
> {
> 	return (int)(addr - ip);
>@@ -57,7 +48,7 @@ notrace unsigned char *ftrace_call_repla
> 	static union ftrace_code_union calc;
> 
> 	calc.e8		= 0xe8;
>-	calc.offset	= ftrace_calc_offset(ip, addr);
>+	calc.offset	= ftrace_calc_offset(ip + CALL_BACK, addr);
> 
> 	/*
> 	 * No locking needed, this must be called via kstop_machine
>@@ -76,9 +67,6 @@ ftrace_modify_code(unsigned long ip, uns
> 	unsigned char newch = new_code[4];
> 	int faulted = 0;
> 
>-	/* move the IP back to the start of the call */
>-	ip -= CALL_BACK;
>-
> 	/*
> 	 * Note: Due to modules and __init, code can
> 	 *  disappear and change, we need to protect against faulting
>@@ -116,8 +104,6 @@ notrace int ftrace_update_ftrace_func(ft
> 	unsigned char old[5], *new;
> 	int ret;
> 
>-	ip += CALL_BACK;
>-
> 	memcpy(old, &ftrace_call, 5);
> 	new = ftrace_call_replace(ip, (unsigned long)func);
> 	ret = ftrace_modify_code(ip, old, new);
>@@ -127,33 +113,22 @@ notrace int ftrace_update_ftrace_func(ft
> 
> notrace int ftrace_mcount_set(unsigned long *data)
> {
>-	unsigned long ip = (long)(&mcount_call);
>-	unsigned long *addr = data;
>-	unsigned char old[5], *new;
>-
>-	/* ip is at the location, but modify code will subtact this */
>-	ip += CALL_BACK;
>-
>-	/*
>-	 * Replace the mcount stub with a pointer to the
>-	 * ip recorder function.
>-	 */
>-	memcpy(old, &mcount_call, 5);
>-	new = ftrace_call_replace(ip, *addr);
>-	*addr = ftrace_modify_code(ip, old, new);
>-
>+	*data = 0;
> 	return 0;
> }
> 
>+asm("\t.section .rodata, \"a\"\nftrace_nop5: "
>+    P6_NOP5
>+    "\t.previous");
>+extern const unsigned char ftrace_nop5[];
>+
> int __init ftrace_dyn_arch_init(void *data)
> {
>-	const unsigned char *const *noptable = find_nop_table();
>-
> 	/* This is running in kstop_machine */
> 
> 	ftrace_mcount_set(data);
> 
>-	ftrace_nop = (unsigned long *)noptable[CALL_BACK];
>+	ftrace_nop = (unsigned long *)ftrace_nop5;
> 
> 	return 0;
> }
>Index: linux-2.6.24.7.noarch/arch/x86/kernel/vmlinux_32.lds.S
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/kernel/vmlinux_32.lds.S
>+++ linux-2.6.24.7.noarch/arch/x86/kernel/vmlinux_32.lds.S
>@@ -134,7 +134,10 @@ SECTIONS
> 	*(.init.text)
> 	_einittext = .;
>   }
>-  .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) { *(.init.data) }
>+  .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
>+	*(.init.data)
>+	MCOUNT_REC()
>+ }
>   . = ALIGN(16);
>   .init.setup : AT(ADDR(.init.setup) - LOAD_OFFSET) {
>   	__setup_start = .;
>Index: linux-2.6.24.7.noarch/arch/x86/kernel/vmlinux_64.lds.S
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/kernel/vmlinux_64.lds.S
>+++ linux-2.6.24.7.noarch/arch/x86/kernel/vmlinux_64.lds.S
>@@ -159,7 +159,10 @@ SECTIONS
> 	_einittext = .;
>   }
>   __initdata_begin = .;
>-  .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) { *(.init.data) }
>+  .init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
>+	*(.init.data)
>+	MCOUNT_REC()
>+    }
>   __initdata_end = .;
>   . = ALIGN(16);
>   __setup_start = .;
>Index: linux-2.6.24.7.noarch/arch/x86/kernel/entry_32.S
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/kernel/entry_32.S
>+++ linux-2.6.24.7.noarch/arch/x86/kernel/entry_32.S
>@@ -1132,19 +1132,6 @@ ENDPROC(xen_failsafe_callback)
> #ifdef CONFIG_DYNAMIC_FTRACE
> 
> ENTRY(mcount)
>-	pushl %eax
>-	pushl %ecx
>-	pushl %edx
>-	movl 0xc(%esp), %eax
>-
>-.globl mcount_call
>-mcount_call:
>-	call ftrace_stub
>-
>-	popl %edx
>-	popl %ecx
>-	popl %eax
>-
> 	ret
> END(mcount)
> 
>Index: linux-2.6.24.7.noarch/arch/x86/kernel/entry_64.S
>===================================================================
>--- linux-2.6.24.7.noarch.orig/arch/x86/kernel/entry_64.S
>+++ linux-2.6.24.7.noarch/arch/x86/kernel/entry_64.S
>@@ -56,31 +56,6 @@
> #ifdef CONFIG_FTRACE
> #ifdef CONFIG_DYNAMIC_FTRACE
> ENTRY(mcount)
>-
>-	subq $0x38, %rsp
>-	movq %rax, (%rsp)
>-	movq %rcx, 8(%rsp)
>-	movq %rdx, 16(%rsp)
>-	movq %rsi, 24(%rsp)
>-	movq %rdi, 32(%rsp)
>-	movq %r8, 40(%rsp)
>-	movq %r9, 48(%rsp)
>-
>-	movq 0x38(%rsp), %rdi
>-
>-.globl mcount_call
>-mcount_call:
>-	call ftrace_stub
>-
>-	movq 48(%rsp), %r9
>-	movq 40(%rsp), %r8
>-	movq 32(%rsp), %rdi
>-	movq 24(%rsp), %rsi
>-	movq 16(%rsp), %rdx
>-	movq 8(%rsp), %rcx
>-	movq (%rsp), %rax
>-	addq $0x38, %rsp
>-
> 	retq
> END(mcount)
>

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Attachments on bug 459141: 314335