Patchwork [1/9] ftrace: align __mcount_loc sections

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Submitter Steven Rostedt
Date Nov. 19, 2008, 9:22 p.m.
Message ID <20081119212333.052756846@goodmis.org>
Download mbox | patch
Permalink /patch/9641/
State Superseded
Headers show

Comments

Steven Rostedt - Nov. 19, 2008, 9:22 p.m.
Impact: add alignment option for recordmcount.pl script

Align the __mcount_loc sections so that architectures with strict
alignment requirements need not worry about performing unaligned
accesses.

This fixes an issue where I was seeing unaligned accesses, which are not
supported on our architecture (the results of an unaligned access are
undefined).

Signed-off-by: Matt Fleming <matthew.fleming@imgtec.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 scripts/recordmcount.pl |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
Steven Rostedt - Nov. 19, 2008, 9:32 p.m.
I need to change my scripts to parse out the first line of all patches, so 
quilt can send out the proper owner. This patch has the following header:

From 626f82959cd00ca804b12543cad86714e74264da Mon Sep 17 00:00:00 2001
From: Matt Fleming <matthew.fleming@imgtec.com>
Date: Fri, 7 Nov 2008 13:26:25 +0000
Subject: [PATCH] ftrace: align __mcount_loc sections


If you pull from my repo, it will all work out. But still, I do not want 
to take credit for someone else's work.

-- Steve

Patch

diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index 6b9fe3e..eeac71c 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -134,6 +134,7 @@  my $section_regex;	# Find the start of a section
 my $function_regex;	# Find the name of a function
 			#    (return offset and func name)
 my $mcount_regex;	# Find the call site to mcount (return offset)
+my $alignment;         # The .align value to use for $mcount_section
 
 if ($arch eq "x86") {
     if ($bits == 64) {
@@ -148,6 +149,7 @@  if ($arch eq "x86_64") {
     $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount([+-]0x[0-9a-zA-Z]+)?\$";
     $type = ".quad";
+    $alignment = 8;
 
     # force flags for this arch
     $ld .= " -m elf_x86_64";
@@ -160,6 +162,7 @@  if ($arch eq "x86_64") {
     $function_regex = "^([0-9a-fA-F]+)\\s+<(.*?)>:";
     $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\smcount\$";
     $type = ".long";
+    $alignment = 4;
 
     # force flags for this arch
     $ld .= " -m elf_i386";
@@ -288,6 +291,7 @@  sub update_funcs
 	    open(FILE, ">$mcount_s") || die "can't create $mcount_s\n";
 	    $opened = 1;
 	    print FILE "\t.section $mcount_section,\"a\",\@progbits\n";
+	    print FILE "\t.align $alignment\n";
 	}
 	printf FILE "\t%s %s + %d\n", $type, $ref_func, $offsets[$i] - $offset;
     }