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ftrace: dynamic ftrace process only text section 

The text section stays in memory without ever leaving. With the exception
of modules, but modules know how to handle that case. With the dynamic
ftrace tracer, we need to make sure that it does not try to modify code
that no longer exists. The only safe section is .text.

This patch changes the recordmcount script to only record the mcount calls
in the .text sections.

Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Steven Rostedt 2008-10-23 09:32:58 -04:00 committed by Ingo Molnar
parent dce9d18add
commit 34698bcbdf
1 changed files with 14 additions and 3 deletions
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17
scripts/recordmcount.pl
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@ -109,6 +109,11 @@ if ($#ARGV < 6) {
my ($arch, $bits, $objdump, $objcopy, $cc,
$ld, $nm, $rm, $mv, $inputfile) = @ARGV;
# Acceptable sections to record.
my %text_sections = (
".text" => 1,
);
$objdump = "objdump" if ((length $objdump) == 0);
$objcopy = "objcopy" if ((length $objcopy) == 0);
$cc = "gcc" if ((length $cc) == 0);
@ -139,7 +144,7 @@ if ($arch eq "x86") {
}
if ($arch eq "x86_64") {
$section_regex = "Disassembly of section";
$section_regex = "Disassembly of section\\s+(\\S+):";
$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
$type = ".quad";
@ -151,7 +156,7 @@ if ($arch eq "x86_64") {
$cc .= " -m64";
} elsif ($arch eq "i386") {
$section_regex = "Disassembly of section";
$section_regex = "Disassembly of section\\s+(\\S+):";
$function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
$mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
$type = ".long";
@ -298,7 +303,13 @@ my $text;
while (<IN>) {
# is it a section?
if (/$section_regex/) {
$read_function = 1;
# Only record text sections that we know are safe
if (defined($text_sections{$1})) {
$read_function = 1;
} else {
$read_function = 0;
}
# print out any recorded offsets
update_funcs() if ($text_found);