[PATCH] Add `make checkstack' target

Jorn Engel <joern@wohnheim.fh-wedel.de>

Adds a `make checkstack' target.  This disassembles and parses vmlinux and
*.ko, generating a sorted list of stack hogs, eg:

0xc0100663 huft_build:                                  1456
0xc01022d3 huft_build:                                  1456
0xc0103127 inflate_dynamic:                             1328
0xc0101487 inflate_dynamic:                             1324
0xc010131f inflate_fixed:                               1168
0xc0102fb7 inflate_fixed:                               1168
0x00000003 sha512_transform:                            984
0xc024aee3 Vpd:                                         952
0x00000003 twofish_setkey:                              804
0x000060c3 isd200_action:                               792
0x0000e6cb nfsd4_proc_compound:                         760
0xc0249087 SkPnmiGetStruct:                             712
....


Supported architectures are alleged to be arm, x86, ia64, mips, mips64, ppc,
ppc64 and s390x.
Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Makefile

@@ -1065,6 +1065,11 @@ buildcheck:
 endif #ifeq ($(config-targets),1)
 endif #ifeq ($(mixed-targets),1)
 
+.PHONY: checkstack
+checkstack:
+	$(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
+	$(PERL) scripts/checkstack.pl $(ARCH)
+
 # FIXME Should go into a make.lib or something 
 # ===========================================================================
 

scripts/checkstack.pl

+#!/usr/bin/perl
+
+#	Check the stack usage of functions
+#
+#	Copyright Joern Engel <joern@wh.fh-wedel.de>
+#	Inspired by Linus Torvalds
+#	Original idea maybe from Keith Owens
+#	s390 port and big speedup by Arnd Bergmann <arnd@bergmann-dalldorf.de>
+#	Mips port by Juan Quintela <quintela@mandrakesoft.com>
+#	IA64 port via Andreas Dilger
+#	Arm port by Holger Schurig
+#	Random bits by Matt Mackall <mpm@selenic.com>
+#
+#	Usage:
+#	objdump -d vmlinux | stackcheck_ppc.pl [arch]
+#
+#	TODO :	Port to all architectures (one regex per arch)
+
+# check for arch
+#
+# $re is used for two matches:
+# $& (whole re) matches the complete objdump line with the stack growth
+# $1 (first bracket) matches the size of the stack growth
+#
+# use anything else and feel the pain ;)
+{
+	my $arch = shift;
+	if ($arch eq "") {
+		$arch = `uname -m`;
+	}
+
+	$x	= "[0-9a-f]";	# hex character
+	$xs	= "[0-9a-f ]";	# hex character or space
+	if ($arch =~ /^arm$/) {
+		#c0008ffc:	e24dd064	sub	sp, sp, #100	; 0x64
+		$re = qr/.*sub.*sp, sp, #(([0-9]{2}|[3-9])[0-9]{2})/o;
+	} elsif ($arch =~ /^i[3456]86$/) {
+		#c0105234:       81 ec ac 05 00 00       sub    $0x5ac,%esp
+		$re = qr/^.*sub    \$(0x$x{3,5}),\%esp$/o;
+	} elsif ($arch =~ /^ia64$/) {
+		#e0000000044011fc:       01 0f fc 8c     adds r12=-384,r12
+		$re = qr/.*adds.*r12=-(([0-9]{2}|[3-9])[0-9]{2}),r12/o;
+	} elsif ($arch =~ /^mips64$/) {
+		#8800402c:       67bdfff0        daddiu  sp,sp,-16
+		$re = qr/.*daddiu.*sp,sp,-(([0-9]{2}|[3-9])[0-9]{2})/o;
+	} elsif ($arch =~ /^mips$/) {
+		#88003254:       27bdffe0        addiu   sp,sp,-32
+		$re = qr/.*addiu.*sp,sp,-(([0-9]{2}|[3-9])[0-9]{2})/o;
+	} elsif ($arch =~ /^ppc$/) {
+		#c00029f4:       94 21 ff 30     stwu    r1,-208(r1)
+		$re = qr/.*stwu.*r1,-($x{3,5})\(r1\)/o;
+	} elsif ($arch =~ /^ppc64$/) {
+		#XXX
+		$re = qr/.*stdu.*r1,-($x{3,5})\(r1\)/o;
+	} elsif ($arch =~ /^s390x?$/) {
+		#   11160:       a7 fb ff 60             aghi   %r15,-160
+		$re = qr/.*ag?hi.*\%r15,-(([0-9]{2}|[3-9])[0-9]{2})/o;
+	} else {
+		print("wrong or unknown architecture\n");
+		exit
+	}
+}
+
+sub bysize($) {
+	($asize = $a) =~ s/.*	+(.*)$/$1/;
+	($bsize = $b) =~ s/.*	+(.*)$/$1/;
+	$bsize <=> $asize
+}
+
+#
+# main()
+#
+$funcre = qr/^$x* \<(.*)\>:$/;
+while ($line = <STDIN>) {
+	if ($line =~ m/$funcre/) {
+		$func = $1;
+	}
+	if ($line =~ m/$re/) {
+		my $size = $1;
+		$size = hex($size) if ($size =~ /^0x/);
+
+		$line =~ m/^($xs*).*/;
+		my $addr = $1;
+		$addr =~ s/ /0/g;
+		$addr = "0x$addr";
+
+		my $intro = "$addr $func:";
+		my $padlen = 56 - length($intro);
+		while ($padlen > 0) {
+			$intro .= '	';
+			$padlen -= 8;
+		}
+		$stack[@stack] = "$intro$size\n";
+	}
+}
+
+@sortedstack = sort bysize @stack;
+
+foreach $i (@sortedstack) {
+	print("$i");
+}