* [PATCH 0/3] clean out Perl from build system.
@ 2009-12-08 9:17 Rob Landley
2009-12-08 9:19 ` [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh Rob Landley
` (3 more replies)
0 siblings, 4 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-08 9:17 UTC (permalink / raw)
To: linux-kernel
Perl was introduced as a build dependency in 2.6.25. My cross-compile
environment does not use perl, so ever since then I've patched it back out.
With these patches I've personally built kernels for x86, x86_64, arm, mips,
powerpc, sparc, sh4, and m68k.
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-08 9:17 [PATCH 0/3] clean out Perl from build system Rob Landley
@ 2009-12-08 9:19 ` Rob Landley
2009-12-09 15:45 ` Michal Marek
2009-12-08 9:21 ` [PATCH 2/3] Remove perl from make headers_install Rob Landley
` (2 subsequent siblings)
3 siblings, 1 reply; 16+ messages in thread
From: Rob Landley @ 2009-12-08 9:19 UTC (permalink / raw)
To: linux-kernel
From: Rob Landley <rob@landley.net>
Replace kernel/timeconst.pl with kernel/timeconst.sh. The new shell script
is much simpler, about 1/4 the size, and runs on Red Hat 9 from 2003.
Signed-off-by: Rob Landley <rob@landley.net>
--
kernel/Makefile | 4
kernel/timeconst.pl | 378 ------------------------------------------
kernel/timeconst.sh | 91 ++++++++++
3 files changed, 93 insertions(+), 380 deletions(-)
diff -ruN linux-2.6.30/kernel/Makefile linux-2.6.30.new/kernel/Makefile
--- linux-2.6.30/kernel/Makefile 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30.new/kernel/Makefile 2009-06-22 14:29:16.000000000 -0500
@@ -123,7 +123,7 @@
$(obj)/time.o: $(obj)/timeconst.h
quiet_cmd_timeconst = TIMEC $@
- cmd_timeconst = $(PERL) $< $(CONFIG_HZ) > $@
+ cmd_timeconst = $(CONFIG_SHELL) $< $(CONFIG_HZ) $@
targets += timeconst.h
-$(obj)/timeconst.h: $(src)/timeconst.pl FORCE
+$(obj)/timeconst.h: $(src)/timeconst.sh FORCE
$(call if_changed,timeconst)
diff -ruN linux-2.6.30/kernel/timeconst.pl linux-2.6.30.new/kernel/timeconst.pl
--- linux-2.6.30/kernel/timeconst.pl 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30.new/kernel/timeconst.pl 1969-12-31 18:00:00.000000000 -0600
@@ -1,378 +0,0 @@
-#!/usr/bin/perl
-# -----------------------------------------------------------------------
-#
-# Copyright 2007-2008 rPath, Inc. - All Rights Reserved
-#
-# This file is part of the Linux kernel, and is made available under
-# the terms of the GNU General Public License version 2 or (at your
-# option) any later version; incorporated herein by reference.
-#
-# -----------------------------------------------------------------------
-#
-
-#
-# Usage: timeconst.pl HZ > timeconst.h
-#
-
-# Precomputed values for systems without Math::BigInt
-# Generated by:
-# timeconst.pl --can 24 32 48 64 100 122 128 200 250 256 300 512 1000 1024 1200
-%canned_values = (
- 24 => [
- '0xa6aaaaab','0x2aaaaaa',26,
- 125,3,
- '0xc49ba5e4','0x1fbe76c8b4',37,
- 3,125,
- '0xa2c2aaab','0xaaaa',16,
- 125000,3,
- '0xc9539b89','0x7fffbce4217d',47,
- 3,125000,
- ], 32 => [
- '0xfa000000','0x6000000',27,
- 125,4,
- '0x83126e98','0xfdf3b645a',36,
- 4,125,
- '0xf4240000','0x0',17,
- 31250,1,
- '0x8637bd06','0x3fff79c842fa',46,
- 1,31250,
- ], 48 => [
- '0xa6aaaaab','0x6aaaaaa',27,
- 125,6,
- '0xc49ba5e4','0xfdf3b645a',36,
- 6,125,
- '0xa2c2aaab','0x15555',17,
- 62500,3,
- '0xc9539b89','0x3fffbce4217d',46,
- 3,62500,
- ], 64 => [
- '0xfa000000','0xe000000',28,
- 125,8,
- '0x83126e98','0x7ef9db22d',35,
- 8,125,
- '0xf4240000','0x0',18,
- 15625,1,
- '0x8637bd06','0x1fff79c842fa',45,
- 1,15625,
- ], 100 => [
- '0xa0000000','0x0',28,
- 10,1,
- '0xcccccccd','0x733333333',35,
- 1,10,
- '0x9c400000','0x0',18,
- 10000,1,
- '0xd1b71759','0x1fff2e48e8a7',45,
- 1,10000,
- ], 122 => [
- '0x8325c53f','0xfbcda3a',28,
- 500,61,
- '0xf9db22d1','0x7fbe76c8b',35,
- 61,500,
- '0x8012e2a0','0x3ef36',18,
- 500000,61,
- '0xffda4053','0x1ffffbce4217',45,
- 61,500000,
- ], 128 => [
- '0xfa000000','0x1e000000',29,
- 125,16,
- '0x83126e98','0x3f7ced916',34,
- 16,125,
- '0xf4240000','0x40000',19,
- 15625,2,
- '0x8637bd06','0xfffbce4217d',44,
- 2,15625,
- ], 200 => [
- '0xa0000000','0x0',29,
- 5,1,
- '0xcccccccd','0x333333333',34,
- 1,5,
- '0x9c400000','0x0',19,
- 5000,1,
- '0xd1b71759','0xfff2e48e8a7',44,
- 1,5000,
- ], 250 => [
- '0x80000000','0x0',29,
- 4,1,
- '0x80000000','0x180000000',33,
- 1,4,
- '0xfa000000','0x0',20,
- 4000,1,
- '0x83126e98','0x7ff7ced9168',43,
- 1,4000,
- ], 256 => [
- '0xfa000000','0x3e000000',30,
- 125,32,
- '0x83126e98','0x1fbe76c8b',33,
- 32,125,
- '0xf4240000','0xc0000',20,
- 15625,4,
- '0x8637bd06','0x7ffde7210be',43,
- 4,15625,
- ], 300 => [
- '0xd5555556','0x2aaaaaaa',30,
- 10,3,
- '0x9999999a','0x1cccccccc',33,
- 3,10,
- '0xd0555556','0xaaaaa',20,
- 10000,3,
- '0x9d495183','0x7ffcb923a29',43,
- 3,10000,
- ], 512 => [
- '0xfa000000','0x7e000000',31,
- 125,64,
- '0x83126e98','0xfdf3b645',32,
- 64,125,
- '0xf4240000','0x1c0000',21,
- 15625,8,
- '0x8637bd06','0x3ffef39085f',42,
- 8,15625,
- ], 1000 => [
- '0x80000000','0x0',31,
- 1,1,
- '0x80000000','0x0',31,
- 1,1,
- '0xfa000000','0x0',22,
- 1000,1,
- '0x83126e98','0x1ff7ced9168',41,
- 1,1000,
- ], 1024 => [
- '0xfa000000','0xfe000000',32,
- 125,128,
- '0x83126e98','0x7ef9db22',31,
- 128,125,
- '0xf4240000','0x3c0000',22,
- 15625,16,
- '0x8637bd06','0x1fff79c842f',41,
- 16,15625,
- ], 1200 => [
- '0xd5555556','0xd5555555',32,
- 5,6,
- '0x9999999a','0x66666666',31,
- 6,5,
- '0xd0555556','0x2aaaaa',22,
- 2500,3,
- '0x9d495183','0x1ffcb923a29',41,
- 3,2500,
- ]
-);
-
-$has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';
-
-sub bint($)
-{
- my($x) = @_;
- return Math::BigInt->new($x);
-}
-
-#
-# Constants for division by reciprocal multiplication.
-# (bits, numerator, denominator)
-#
-sub fmul($$$)
-{
- my ($b,$n,$d) = @_;
-
- $n = bint($n);
- $d = bint($d);
-
- return scalar (($n << $b)+$d-bint(1))/$d;
-}
-
-sub fadj($$$)
-{
- my($b,$n,$d) = @_;
-
- $n = bint($n);
- $d = bint($d);
-
- $d = $d/bgcd($n, $d);
- return scalar (($d-bint(1)) << $b)/$d;
-}
-
-sub fmuls($$$) {
- my($b,$n,$d) = @_;
- my($s,$m);
- my($thres) = bint(1) << ($b-1);
-
- $n = bint($n);
- $d = bint($d);
-
- for ($s = 0; 1; $s++) {
- $m = fmul($s,$n,$d);
- return $s if ($m >= $thres);
- }
- return 0;
-}
-
-# Generate a hex value if the result fits in 64 bits;
-# otherwise skip.
-sub bignum_hex($) {
- my($x) = @_;
- my $s = $x->as_hex();
-
- return (length($s) > 18) ? undef : $s;
-}
-
-# Provides mul, adj, and shr factors for a specific
-# (bit, time, hz) combination
-sub muladj($$$) {
- my($b, $t, $hz) = @_;
- my $s = fmuls($b, $t, $hz);
- my $m = fmul($s, $t, $hz);
- my $a = fadj($s, $t, $hz);
- return (bignum_hex($m), bignum_hex($a), $s);
-}
-
-# Provides numerator, denominator values
-sub numden($$) {
- my($n, $d) = @_;
- my $g = bgcd($n, $d);
- return ($n/$g, $d/$g);
-}
-
-# All values for a specific (time, hz) combo
-sub conversions($$) {
- my ($t, $hz) = @_;
- my @val = ();
-
- # HZ_TO_xx
- push(@val, muladj(32, $t, $hz));
- push(@val, numden($t, $hz));
-
- # xx_TO_HZ
- push(@val, muladj(32, $hz, $t));
- push(@val, numden($hz, $t));
-
- return @val;
-}
-
-sub compute_values($) {
- my($hz) = @_;
- my @val = ();
- my $s, $m, $a, $g;
-
- if (!$has_bigint) {
- die "$0: HZ == $hz not canned and ".
- "Math::BigInt not available\n";
- }
-
- # MSEC conversions
- push(@val, conversions(1000, $hz));
-
- # USEC conversions
- push(@val, conversions(1000000, $hz));
-
- return @val;
-}
-
-sub outputval($$)
-{
- my($name, $val) = @_;
- my $csuf;
-
- if (defined($val)) {
- if ($name !~ /SHR/) {
- $val = "U64_C($val)";
- }
- printf "#define %-23s %s\n", $name.$csuf, $val.$csuf;
- }
-}
-
-sub output($@)
-{
- my($hz, @val) = @_;
- my $pfx, $bit, $suf, $s, $m, $a;
-
- print "/* Automatically generated by kernel/timeconst.pl */\n";
- print "/* Conversion constants for HZ == $hz */\n";
- print "\n";
- print "#ifndef KERNEL_TIMECONST_H\n";
- print "#define KERNEL_TIMECONST_H\n";
- print "\n";
-
- print "#include <linux/param.h>\n";
- print "#include <linux/types.h>\n";
-
- print "\n";
- print "#if HZ != $hz\n";
- print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n";
- print "#endif\n";
- print "\n";
-
- foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ',
- 'HZ_TO_USEC','USEC_TO_HZ') {
- foreach $bit (32) {
- foreach $suf ('MUL', 'ADJ', 'SHR') {
- outputval("${pfx}_$suf$bit", shift(@val));
- }
- }
- foreach $suf ('NUM', 'DEN') {
- outputval("${pfx}_$suf", shift(@val));
- }
- }
-
- print "\n";
- print "#endif /* KERNEL_TIMECONST_H */\n";
-}
-
-# Pretty-print Perl values
-sub perlvals(@) {
- my $v;
- my @l = ();
-
- foreach $v (@_) {
- if (!defined($v)) {
- push(@l, 'undef');
- } elsif ($v =~ /^0x/) {
- push(@l, "\'".$v."\'");
- } else {
- push(@l, $v.'');
- }
- }
- return join(',', @l);
-}
-
-($hz) = @ARGV;
-
-# Use this to generate the %canned_values structure
-if ($hz eq '--can') {
- shift(@ARGV);
- @hzlist = sort {$a <=> $b} (@ARGV);
-
- print "# Precomputed values for systems without Math::BigInt\n";
- print "# Generated by:\n";
- print "# timeconst.pl --can ", join(' ', @hzlist), "\n";
- print "\%canned_values = (\n";
- my $pf = "\t";
- foreach $hz (@hzlist) {
- my @values = compute_values($hz);
- print "$pf$hz => [\n";
- while (scalar(@values)) {
- my $bit;
- foreach $bit (32) {
- my $m = shift(@values);
- my $a = shift(@values);
- my $s = shift(@values);
- print "\t\t", perlvals($m,$a,$s), ",\n";
- }
- my $n = shift(@values);
- my $d = shift(@values);
- print "\t\t", perlvals($n,$d), ",\n";
- }
- print "\t]";
- $pf = ', ';
- }
- print "\n);\n";
-} else {
- $hz += 0; # Force to number
- if ($hz < 1) {
- die "Usage: $0 HZ\n";
- }
-
- @val = @{$canned_values{$hz}};
- if (!defined(@val)) {
- @val = compute_values($hz);
- }
- output($hz, @val);
-}
-exit 0;
diff -ruN linux-2.6.30/kernel/timeconst.sh linux-2.6.30.new/kernel/timeconst.sh
--- linux-2.6.30/kernel/timeconst.sh 1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.30.new/kernel/timeconst.sh 2009-06-22 14:29:16.000000000 -0500
@@ -0,0 +1,148 @@
+#!/bin/sh
+
+if [ $# -ne 2 ]
+then
+ echo "Usage: timeconst.sh HZ FILENAME"
+ echo
+ echo "Generate a header file with constants for coverting between"
+ echo "decimal HZ timer ticks and milisecond or microsecond delays."
+ echo
+ exit 1
+fi
+
+HZ=$1
+shift
+FILENAME=$1
+
+# Sanity test: even the shell in Red Hat 9 (circa 2003) supported 64 bit math.
+
+if [ $((1 << 32)) -lt 0 ]
+then
+ echo "timeconst.sh needs a shell with 64 bit math, such as bash,"
+ echo "busybox ash, or dash running on a 64 bit host."
+ exit 1
+fi
+
+# If this script exits for any reason before this trap is removed,
+# delete the output file so a partial file won't confuse the build.
+
+trap "rm $FILENAME" EXIT
+
+# Output start of header file
+
+cat > $FILENAME << EOF || exit 1
+/* Automatically generated by kernel/timeconst.sh */
+/* Conversion constants for HZ == $HZ */
+
+#ifndef __KERNEL_TIMECONST_H
+#define __KERNEL_TIMECONST_H
+
+#include <linux/param.h>
+#include <linux/types.h>
+
+#if HZ != $HZ
+#error "kernel/timeconst.h has the wrong HZ value!"
+#endif
+
+EOF
+
+# For both Milliseconds and Microseconds
+
+cat << EOF |
+MSEC 1000
+USEC 1000000
+EOF
+while read NAME PERIOD
+do
+ # Find greatest common denominator (using Euclid's algorithm)
+
+ A=$HZ
+ B=$PERIOD
+
+ while [ $B -ne 0 ]
+ do
+ C=$(( $A % $B ))
+ A=$B
+ B=$C
+ done
+
+ GCD=$A
+
+ # Do this for each direction (HZ_TO_PERIOD and PERIOD_TO_HZ)
+
+ for DIRECTION in 0 1
+ do
+ if [ $DIRECTION -eq 0 ]
+ then
+ CONVERT="HZ_TO_${NAME}"
+ FROM=$HZ
+ TO=$PERIOD
+ else
+ CONVERT="${NAME}_TO_HZ"
+ FROM=$PERIOD
+ TO=$HZ
+ fi
+
+ # Calculate 32 significant bits of MUL32 data.
+
+ SHIFT=0
+ while true
+ do
+ # This can't overflow 64 bit math. Pathological case
+ # (TO=1, FROM=1000000) uses around 32+20=52 bits.
+
+ MUL32=$(( ( ( $TO << $SHIFT ) + $FROM - 1 ) / $FROM ))
+
+ # Keep increasing $SHIFT until we've got 32 bits.
+
+ [ $MUL32 -gt $(( 1 << 31 )) ] && break
+ SHIFT=$(( $SHIFT + 1 ))
+ done
+ MUL32=$( printf %x $MUL32 )
+
+ # ADJ32 is just (((FROM/GCD)-1)<<SHIFT)/(FROM/GCD) but this
+ # can overflow 64 bit math (examples, HZ=24 or HZ=122).
+ # Pathological case could use 32+20+20=72 bits. (And this is
+ # the pathological case because a larger $HZ results in a
+ # smaller $SHIFT, so even insane HZ>USEC cases should be ok.)
+
+ # To get around this, we chop the bottom 32 bits off the
+ # calculation and then reassemble it to avoid overflow:
+ # 32+64=96, which is > 72.
+
+ ADJ32=$(( $FROM / $GCD ))
+ if [ $SHIFT -gt 32 ]
+ then
+ UPPER=$(( ( $ADJ32 - 1 ) << ( $SHIFT - 32 ) ))
+ LOWER=$(( ( $UPPER % $ADJ32 ) << 32 ))
+ ADJ32=$(( ( ( $UPPER / $ADJ32 ) << 32 ) + ( $LOWER / $ADJ32 )))
+ else
+ ADJ32=$(( ( ( $ADJ32 - 1 ) << $SHIFT) / $ADJ32 ))
+ fi
+ ADJ32=$( printf %x $ADJ32 )
+
+ NUM=$(( $TO / $GCD ))
+ DEN=$(( $FROM / $GCD ))
+
+ # Output next chunk of header data to file
+
+ (
+ echo "#define ${CONVERT}_MUL32 U64_C(0x$MUL32)" &&
+ echo "#define ${CONVERT}_ADJ32 U64_C(0x$ADJ32)" &&
+ echo "#define ${CONVERT}_SHR32 $SHIFT" &&
+ echo "#define ${CONVERT}_NUM U64_C($NUM)" &&
+ echo "#define ${CONVERT}_DEN U64_C($DEN)"
+ ) >> $FILENAME || exit 1
+ done
+done
+
+(
+ echo
+ echo "#endif /* __KERNEL_TIMECHONST_H */"
+) >> $FILENAME || exit 1
+
+# Don't rm $FILENAME on exit anymore.
+
+trap "" EXIT
+
+exit 0
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 2/3] Remove perl from make headers_install
2009-12-08 9:17 [PATCH 0/3] clean out Perl from build system Rob Landley
2009-12-08 9:19 ` [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh Rob Landley
@ 2009-12-08 9:21 ` Rob Landley
2009-12-08 9:22 ` [PATCH 3/3] Convert kernel/cpu/mkcapflags.pl to kernel/cpu/mkcapflags.sh Rob Landley
2009-12-08 10:23 ` [PATCH 0/3] clean out Perl from build system Michal Marek
3 siblings, 0 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-08 9:21 UTC (permalink / raw)
To: linux-kernel
From: Rob Landley <rob@landley.net>
Remove perl from make headers_install by replacing a perl script (doing
a simple regex search and replace) with a smaller and faster shell script
implementation. The new shell script is a single for loop calling sed and
piping its output through unifdef to produce the target file.
Signed-off-by: Rob Landley <rob@landley.net>
---
scripts/Makefile.headersinst | 6 ++--
scripts/headers_install.pl | 49 ---------------------------------
scripts/headers_install.sh | 39 ++++++++++++++++++++++++++
3 files changed, 42 insertions(+), 52 deletions(-)
diff -ruN linux-2.6.30.old/scripts/headers_install.pl linux-2.6.30/scripts/headers_install.pl
--- linux-2.6.30.old/scripts/headers_install.pl 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30/scripts/headers_install.pl 1969-12-31 18:00:00.000000000 -0600
@@ -1,49 +0,0 @@
-#!/usr/bin/perl -w
-#
-# headers_install prepare the listed header files for use in
-# user space and copy the files to their destination.
-#
-# Usage: headers_install.pl readdir installdir arch [files...]
-# readdir: dir to open files
-# installdir: dir to install the files
-# arch: current architecture
-# arch is used to force a reinstallation when the arch
-# changes because kbuild then detect a command line change.
-# files: list of files to check
-#
-# Step in preparation for users space:
-# 1) Drop all use of compiler.h definitions
-# 2) Drop include of compiler.h
-# 3) Drop all sections defined out by __KERNEL__ (using unifdef)
-
-use strict;
-
-my ($readdir, $installdir, $arch, @files) = @ARGV;
-
-my $unifdef = "scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__";
-
-foreach my $file (@files) {
- local *INFILE;
- local *OUTFILE;
- my $tmpfile = "$installdir/$file.tmp";
- open(INFILE, "<$readdir/$file")
- or die "$readdir/$file: $!\n";
- open(OUTFILE, ">$tmpfile") or die "$tmpfile: $!\n";
- while (my $line = <INFILE>) {
- $line =~ s/([\s(])__user\s/$1/g;
- $line =~ s/([\s(])__force\s/$1/g;
- $line =~ s/([\s(])__iomem\s/$1/g;
- $line =~ s/\s__attribute_const__\s/ /g;
- $line =~ s/\s__attribute_const__$//g;
- $line =~ s/^#include <linux\/compiler.h>//;
- $line =~ s/(^|\s)(inline)\b/$1__$2__/g;
- $line =~ s/(^|\s)(asm)\b(\s|[(]|$)/$1__$2__$3/g;
- $line =~ s/(^|\s|[(])(volatile)\b(\s|[(]|$)/$1__$2__$3/g;
- printf OUTFILE "%s", $line;
- }
- close OUTFILE;
- close INFILE;
- system $unifdef . " $tmpfile > $installdir/$file";
- unlink $tmpfile;
-}
-exit 0;
diff -ruN linux-2.6.30.old/scripts/headers_install.sh linux-2.6.30/scripts/headers_install.sh
--- linux-2.6.30.old/scripts/headers_install.sh 1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.30/scripts/headers_install.sh 2009-06-22 16:21:23.000000000 -0500
@@ -0,0 +1,39 @@
+#!/bin/sh
+
+if [ $# -lt 2 ]
+then
+ echo "Usage: headers_install.sh INDIR OUTDIR [FILES...]
+ echo
+ echo "Prepares kernel header files for use by user space, by removing"
+ echo "all compiler.h definitions and #includes, removing any"
+ echo "#ifdef __KERNEL__ sections, and putting __underscores__ around"
+ echo "asm/inline/volatile keywords."
+ echo
+ echo "INDIR: directory to read each kernel header FILE from."
+ echo "OUTDIR: directory to write each userspace header FILE to."
+ echo "FILES: list of header files to operate on."
+
+ exit 1
+fi
+
+# Grab arguments
+
+INDIR="$1"
+shift
+OUTDIR="$1"
+shift
+
+# Iterate through files listed on command line
+
+for i in "$@"
+do
+ sed -r \
+ -e 's/([ \t(])(__user|__force|__iomem)[ \t]/\1/g' \
+ -e 's/__attribute_const__([ \t]|$)/\1/g' \
+ -e 's@^#include <linux/compiler.h>@@' \
+ -e 's/(^|[ \t])(inline|asm|volatile)([ \t(]|$)/\1__\2__\3/g' \
+ "$INDIR/$i" |
+ scripts/unifdef -U__KERNEL__ -D__EXPORTED_HEADERS__ - > "$OUTDIR/$i"
+done
+
+exit 0
diff -ruN linux-2.6.30.old/scripts/Makefile.headersinst linux-2.6.30/scripts/Makefile.headersinst
--- linux-2.6.30.old/scripts/Makefile.headersinst 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30/scripts/Makefile.headersinst 2009-06-22 16:21:23.000000000 -0500
@@ -46,8 +46,8 @@
quiet_cmd_install = INSTALL $(printdir) ($(words $(all-files))\
file$(if $(word 2, $(all-files)),s))
cmd_install = \
- $(PERL) $< $(srctree)/$(obj) $(install) $(SRCARCH) $(header-y); \
- $(PERL) $< $(objtree)/$(obj) $(install) $(SRCARCH) $(objhdr-y); \
+ $(CONFIG_SHELL) $< $(srctree)/$(obj) $(install) $(header-y); \
+ $(CONFIG_SHELL) $< $(objtree)/$(obj) $(install) $(objhdr-y); \
touch $@
quiet_cmd_remove = REMOVE $(unwanted)
@@ -70,7 +70,7 @@
@:
targets += $(install-file)
-$(install-file): scripts/headers_install.pl $(input-files) FORCE
+$(install-file): scripts/headers_install.sh $(input-files) FORCE
$(if $(unwanted),$(call cmd,remove),)
$(if $(wildcard $(dir $@)),,$(shell mkdir -p $(dir $@)))
$(call if_changed,install)
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 3/3] Convert kernel/cpu/mkcapflags.pl to kernel/cpu/mkcapflags.sh
2009-12-08 9:17 [PATCH 0/3] clean out Perl from build system Rob Landley
2009-12-08 9:19 ` [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh Rob Landley
2009-12-08 9:21 ` [PATCH 2/3] Remove perl from make headers_install Rob Landley
@ 2009-12-08 9:22 ` Rob Landley
2009-12-08 10:23 ` [PATCH 0/3] clean out Perl from build system Michal Marek
3 siblings, 0 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-08 9:22 UTC (permalink / raw)
To: linux-kernel
From: Rob Landley <rob@landley.net>
Convert kernel/cpu/mkcapflags.pl to kernel/cpu/mkcapflags.sh.
This script generates kernel/cpu/capflags.c from include/asm/cpufeature.h.
Signed-off-by: Rob Landley <rob@landley.net>
---
arch/x86/kernel/cpu/Makefile | 4 +--
arch/x86/kernel/cpu/mkcapflags.pl | 32 ----------------------------
arch/x86/kernel/cpu/mkcapflags.sh | 28 ++++++++++++++++++++++++
3 files changed, 30 insertions(+), 34 deletions(-)
diff -ruN linux-2.6.30.old/arch/x86/kernel/cpu/Makefile linux-2.6.30/arch/x86/kernel/cpu/Makefile
--- linux-2.6.30.old/arch/x86/kernel/cpu/Makefile 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30/arch/x86/kernel/cpu/Makefile 2009-06-22 16:39:06.000000000 -0500
@@ -36,10 +36,10 @@
obj-$(CONFIG_X86_LOCAL_APIC) += perfctr-watchdog.o
quiet_cmd_mkcapflags = MKCAP $@
- cmd_mkcapflags = $(PERL) $(srctree)/$(src)/mkcapflags.pl $< $@
+ cmd_mkcapflags = $(CONFIG_SHELL) $(srctree)/$(src)/mkcapflags.sh $< $@
cpufeature = $(src)/../../include/asm/cpufeature.h
targets += capflags.c
-$(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.pl FORCE
+$(obj)/capflags.c: $(cpufeature) $(src)/mkcapflags.sh FORCE
$(call if_changed,mkcapflags)
diff -ruN linux-2.6.30.old/arch/x86/kernel/cpu/mkcapflags.pl
linux-2.6.30/arch/x86/kernel/cpu/mkcapflags.pl
--- linux-2.6.30.old/arch/x86/kernel/cpu/mkcapflags.pl 2009-06-09 22:05:27.000000000 -0500
+++ linux-2.6.30/arch/x86/kernel/cpu/mkcapflags.pl 1969-12-31 18:00:00.000000000 -0600
@@ -1,32 +0,0 @@
-#!/usr/bin/perl
-#
-# Generate the x86_cap_flags[] array from include/asm-x86/cpufeature.h
-#
-
-($in, $out) = @ARGV;
-
-open(IN, "< $in\0") or die "$0: cannot open: $in: $!\n";
-open(OUT, "> $out\0") or die "$0: cannot create: $out: $!\n";
-
-print OUT "#include <asm/cpufeature.h>\n\n";
-print OUT "const char * const x86_cap_flags[NCAPINTS*32] = {\n";
-
-while (defined($line = <IN>)) {
- if ($line =~ /^\s*\#\s*define\s+(X86_FEATURE_(\S+))\s+(.*)$/) {
- $macro = $1;
- $feature = $2;
- $tail = $3;
- if ($tail =~ /\/\*\s*\"([^"]*)\".*\*\//) {
- $feature = $1;
- }
-
- if ($feature ne '') {
- printf OUT "\t%-32s = \"%s\",\n",
- "[$macro]", "\L$feature";
- }
- }
-}
-print OUT "};\n";
-
-close(IN);
-close(OUT);
diff -ruN linux-2.6.30.old/arch/x86/kernel/cpu/mkcapflags.sh
linux-2.6.30/arch/x86/kernel/cpu/mkcapflags.sh
--- linux-2.6.30.old/arch/x86/kernel/cpu/mkcapflags.sh 1969-12-31 18:00:00.000000000 -0600
+++ linux-2.6.30/arch/x86/kernel/cpu/mkcapflags.sh 2009-06-22 16:39:06.000000000 -0500
@@ -0,0 +1,28 @@
+#!/bin/sh
+#
+# Generate the x86_cap_flags[] array from include/asm/cpufeature.h
+#
+
+IN=$1
+OUT=$2
+
+(
+ echo "#include <asm/cpufeature.h>"
+ echo ""
+ echo "const char * const x86_cap_flags[NCAPINTS*32] = {"
+
+ # Iterate through any input lines starting with #define X86_FEATURE_
+ sed -n -e 's/\t/ /g' -e 's/^ *# *define *X86_FEATURE_//p' $IN |
+ while read i
+ do
+ # Name is everything up to the first whitespace
+ NAME="$(echo "$i" | sed 's/ .*//')"
+
+ # If the /* comment */ starts with a quote string, grab that.
+ VALUE="$(echo "$i" | sed -n 's@.*/\* *\("[^"]*"\).*\*/@\1@p')"
+ [ -z "$VALUE" ] && VALUE="\"$(echo "$NAME" | tr A-Z a-z)\""
+
+ [ "$VALUE" != '""' ] && echo " [X86_FEATURE_$NAME] = $VALUE,"
+ done
+ echo "};"
+) > $OUT
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 0/3] clean out Perl from build system.
2009-12-08 9:17 [PATCH 0/3] clean out Perl from build system Rob Landley
` (2 preceding siblings ...)
2009-12-08 9:22 ` [PATCH 3/3] Convert kernel/cpu/mkcapflags.pl to kernel/cpu/mkcapflags.sh Rob Landley
@ 2009-12-08 10:23 ` Michal Marek
2009-12-08 15:08 ` Rob Landley
3 siblings, 1 reply; 16+ messages in thread
From: Michal Marek @ 2009-12-08 10:23 UTC (permalink / raw)
To: Rob Landley; +Cc: linux-kernel, linux-kbuild
On 8.12.2009 10:17, Rob Landley wrote:
> Perl was introduced as a build dependency in 2.6.25. My cross-compile
> environment does not use perl, so ever since then I've patched it back out.
>
> With these patches I've personally built kernels for x86, x86_64, arm, mips,
> powerpc, sparc, sh4, and m68k.
Hi Rob,
you should CC linux-kbuild@ on patches like this (added now, the whole
series is at http://lkml.org/lkml/2009/12/8/93).
Michal
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 0/3] clean out Perl from build system.
2009-12-08 10:23 ` [PATCH 0/3] clean out Perl from build system Michal Marek
@ 2009-12-08 15:08 ` Rob Landley
0 siblings, 0 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-08 15:08 UTC (permalink / raw)
To: Michal Marek; +Cc: linux-kernel, linux-kbuild
On Tuesday 08 December 2009 04:23:06 Michal Marek wrote:
> On 8.12.2009 10:17, Rob Landley wrote:
> > Perl was introduced as a build dependency in 2.6.25. My cross-compile
> > environment does not use perl, so ever since then I've patched it back
> > out.
> >
> > With these patches I've personally built kernels for x86, x86_64, arm,
> > mips, powerpc, sparc, sh4, and m68k.
>
> Hi Rob,
>
> you should CC linux-kbuild@ on patches like this (added now, the whole
> series is at http://lkml.org/lkml/2009/12/8/93).
>
> Michal
Thanks. LWN said Sam Ravnborg was stepping down, and I haven't kept up with
who's in charge now.
Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-08 9:19 ` [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh Rob Landley
@ 2009-12-09 15:45 ` Michal Marek
2009-12-09 23:40 ` Rob Landley
0 siblings, 1 reply; 16+ messages in thread
From: Michal Marek @ 2009-12-09 15:45 UTC (permalink / raw)
To: Rob Landley; +Cc: linux-kernel, H. Peter Anvin, linux-kbuild
[CC hpa who wrote the timeconst.pl script]
On 8.12.2009 10:19, Rob Landley wrote:
> From: Rob Landley <rob@landley.net>
>
> Replace kernel/timeconst.pl with kernel/timeconst.sh. The new shell script
> is much simpler, about 1/4 the size, and runs on Red Hat 9 from 2003.
I tried the shell script with the precomputed values in timeconst.pl and
it gave me different results than the perl version for 250 and 1000:
with HZ=250:
--- perl
+++ bash
@@ -8,14 +8,14 @@
#error "kernel/timeconst.h has the wrong HZ value!"
#endif
-#define HZ_TO_MSEC_MUL32 U64_C(0x80000000)
+#define HZ_TO_MSEC_MUL32 U64_C(0x100000000)
#define HZ_TO_MSEC_ADJ32 U64_C(0x0)
-#define HZ_TO_MSEC_SHR32 29
+#define HZ_TO_MSEC_SHR32 30
#define HZ_TO_MSEC_NUM U64_C(4)
#define HZ_TO_MSEC_DEN U64_C(1)
-#define MSEC_TO_HZ_MUL32 U64_C(0x80000000)
-#define MSEC_TO_HZ_ADJ32 U64_C(0x180000000)
-#define MSEC_TO_HZ_SHR32 33
+#define MSEC_TO_HZ_MUL32 U64_C(0x100000000)
+#define MSEC_TO_HZ_ADJ32 U64_C(0x300000000)
+#define MSEC_TO_HZ_SHR32 34
#define MSEC_TO_HZ_NUM U64_C(1)
#define MSEC_TO_HZ_DEN U64_C(4)
#define HZ_TO_USEC_MUL32 U64_C(0xfa000000)
and with HZ=1000:
--- perl
+++ bash
@@ -8,14 +8,14 @@
#error "kernel/timeconst.h has the wrong HZ value!"
#endif
-#define HZ_TO_MSEC_MUL32 U64_C(0x80000000)
+#define HZ_TO_MSEC_MUL32 U64_C(0x100000000)
#define HZ_TO_MSEC_ADJ32 U64_C(0x0)
-#define HZ_TO_MSEC_SHR32 31
+#define HZ_TO_MSEC_SHR32 32
#define HZ_TO_MSEC_NUM U64_C(1)
#define HZ_TO_MSEC_DEN U64_C(1)
-#define MSEC_TO_HZ_MUL32 U64_C(0x80000000)
+#define MSEC_TO_HZ_MUL32 U64_C(0x100000000)
#define MSEC_TO_HZ_ADJ32 U64_C(0x0)
-#define MSEC_TO_HZ_SHR32 31
+#define MSEC_TO_HZ_SHR32 32
#define MSEC_TO_HZ_NUM U64_C(1)
#define MSEC_TO_HZ_DEN U64_C(1)
#define HZ_TO_USEC_MUL32 U64_C(0xfa000000)
$ bash --version
GNU bash, version 4.0.33(1)-release (x86_64-suse-linux-gnu)
...
You're trying to avoid the build dependency on Perl. What about adding a
timeconst.h_shipped with the precomputed values from timeconst.pl:
#if HZ == 24
#define ...
...
#endif
#if HZ == 32
...
#endif
...
#ifndef HZ_TO_MSEC_MUL32
# error "Unknown HZ value, please update kernel/timeconst.h using
kernel/timeconst.pl"
#endif
plus some makefile automagic to run the script iff the HZ value isn't
precomputed. Then you would only need Perl for exotic HZ configurations.
>
> Signed-off-by: Rob Landley <rob@landley.net>
> --
>
> kernel/Makefile | 4
> kernel/timeconst.pl | 378 ------------------------------------------
> kernel/timeconst.sh | 91 ++++++++++
> 3 files changed, 93 insertions(+), 380 deletions(-)
>
> diff -ruN linux-2.6.30/kernel/Makefile linux-2.6.30.new/kernel/Makefile
> --- linux-2.6.30/kernel/Makefile 2009-06-09 22:05:27.000000000 -0500
> +++ linux-2.6.30.new/kernel/Makefile 2009-06-22 14:29:16.000000000 -0500
> @@ -123,7 +123,7 @@
> $(obj)/time.o: $(obj)/timeconst.h
>
> quiet_cmd_timeconst = TIMEC $@
> - cmd_timeconst = $(PERL) $< $(CONFIG_HZ) > $@
> + cmd_timeconst = $(CONFIG_SHELL) $< $(CONFIG_HZ) $@
> targets += timeconst.h
> -$(obj)/timeconst.h: $(src)/timeconst.pl FORCE
> +$(obj)/timeconst.h: $(src)/timeconst.sh FORCE
> $(call if_changed,timeconst)
> diff -ruN linux-2.6.30/kernel/timeconst.pl linux-2.6.30.new/kernel/timeconst.pl
> --- linux-2.6.30/kernel/timeconst.pl 2009-06-09 22:05:27.000000000 -0500
> +++ linux-2.6.30.new/kernel/timeconst.pl 1969-12-31 18:00:00.000000000 -0600
> @@ -1,378 +0,0 @@
> -#!/usr/bin/perl
> -# -----------------------------------------------------------------------
> -#
> -# Copyright 2007-2008 rPath, Inc. - All Rights Reserved
> -#
> -# This file is part of the Linux kernel, and is made available under
> -# the terms of the GNU General Public License version 2 or (at your
> -# option) any later version; incorporated herein by reference.
> -#
> -# -----------------------------------------------------------------------
> -#
> -
> -#
> -# Usage: timeconst.pl HZ > timeconst.h
[snip]
> diff -ruN linux-2.6.30/kernel/timeconst.sh linux-2.6.30.new/kernel/timeconst.sh
> --- linux-2.6.30/kernel/timeconst.sh 1969-12-31 18:00:00.000000000 -0600
> +++ linux-2.6.30.new/kernel/timeconst.sh 2009-06-22 14:29:16.000000000 -0500
> @@ -0,0 +1,148 @@
> +#!/bin/sh
> +
> +if [ $# -ne 2 ]
> +then
> + echo "Usage: timeconst.sh HZ FILENAME"
> + echo
> + echo "Generate a header file with constants for coverting between"
> + echo "decimal HZ timer ticks and milisecond or microsecond delays."
> + echo
> + exit 1
> +fi
> +
> +HZ=$1
> +shift
> +FILENAME=$1
> +
> +# Sanity test: even the shell in Red Hat 9 (circa 2003) supported 64 bit math.
> +
> +if [ $((1 << 32)) -lt 0 ]
> +then
> + echo "timeconst.sh needs a shell with 64 bit math, such as bash,"
> + echo "busybox ash, or dash running on a 64 bit host."
> + exit 1
> +fi
> +
> +# If this script exits for any reason before this trap is removed,
> +# delete the output file so a partial file won't confuse the build.
> +
> +trap "rm $FILENAME" EXIT
> +
> +# Output start of header file
> +
> +cat > $FILENAME << EOF || exit 1
> +/* Automatically generated by kernel/timeconst.sh */
> +/* Conversion constants for HZ == $HZ */
> +
> +#ifndef __KERNEL_TIMECONST_H
> +#define __KERNEL_TIMECONST_H
> +
> +#include <linux/param.h>
> +#include <linux/types.h>
> +
> +#if HZ != $HZ
> +#error "kernel/timeconst.h has the wrong HZ value!"
> +#endif
> +
> +EOF
> +
> +# For both Milliseconds and Microseconds
> +
> +cat << EOF |
> +MSEC 1000
> +USEC 1000000
> +EOF
> +while read NAME PERIOD
> +do
> + # Find greatest common denominator (using Euclid's algorithm)
> +
> + A=$HZ
> + B=$PERIOD
> +
> + while [ $B -ne 0 ]
> + do
> + C=$(( $A % $B ))
> + A=$B
> + B=$C
> + done
> +
> + GCD=$A
> +
> + # Do this for each direction (HZ_TO_PERIOD and PERIOD_TO_HZ)
> +
> + for DIRECTION in 0 1
> + do
> + if [ $DIRECTION -eq 0 ]
> + then
> + CONVERT="HZ_TO_${NAME}"
> + FROM=$HZ
> + TO=$PERIOD
> + else
> + CONVERT="${NAME}_TO_HZ"
> + FROM=$PERIOD
> + TO=$HZ
> + fi
> +
> + # Calculate 32 significant bits of MUL32 data.
> +
> + SHIFT=0
> + while true
> + do
> + # This can't overflow 64 bit math. Pathological case
> + # (TO=1, FROM=1000000) uses around 32+20=52 bits.
> +
> + MUL32=$(( ( ( $TO << $SHIFT ) + $FROM - 1 ) / $FROM ))
> +
> + # Keep increasing $SHIFT until we've got 32 bits.
> +
> + [ $MUL32 -gt $(( 1 << 31 )) ] && break
> + SHIFT=$(( $SHIFT + 1 ))
> + done
> + MUL32=$( printf %x $MUL32 )
> +
> + # ADJ32 is just (((FROM/GCD)-1)<<SHIFT)/(FROM/GCD) but this
> + # can overflow 64 bit math (examples, HZ=24 or HZ=122).
> + # Pathological case could use 32+20+20=72 bits. (And this is
> + # the pathological case because a larger $HZ results in a
> + # smaller $SHIFT, so even insane HZ>USEC cases should be ok.)
> +
> + # To get around this, we chop the bottom 32 bits off the
> + # calculation and then reassemble it to avoid overflow:
> + # 32+64=96, which is > 72.
> +
> + ADJ32=$(( $FROM / $GCD ))
> + if [ $SHIFT -gt 32 ]
> + then
> + UPPER=$(( ( $ADJ32 - 1 ) << ( $SHIFT - 32 ) ))
> + LOWER=$(( ( $UPPER % $ADJ32 ) << 32 ))
> + ADJ32=$(( ( ( $UPPER / $ADJ32 ) << 32 ) + ( $LOWER / $ADJ32 )))
> + else
> + ADJ32=$(( ( ( $ADJ32 - 1 ) << $SHIFT) / $ADJ32 ))
> + fi
> + ADJ32=$( printf %x $ADJ32 )
> +
> + NUM=$(( $TO / $GCD ))
> + DEN=$(( $FROM / $GCD ))
> +
> + # Output next chunk of header data to file
> +
> + (
> + echo "#define ${CONVERT}_MUL32 U64_C(0x$MUL32)" &&
> + echo "#define ${CONVERT}_ADJ32 U64_C(0x$ADJ32)" &&
> + echo "#define ${CONVERT}_SHR32 $SHIFT" &&
> + echo "#define ${CONVERT}_NUM U64_C($NUM)" &&
> + echo "#define ${CONVERT}_DEN U64_C($DEN)"
> + ) >> $FILENAME || exit 1
> + done
> +done
> +
> +(
> + echo
> + echo "#endif /* __KERNEL_TIMECHONST_H */"
^
Should be "__KERNEL_TIMECONST_H".
> +) >> $FILENAME || exit 1
> +
> +# Don't rm $FILENAME on exit anymore.
> +
> +trap "" EXIT
> +
> +exit 0
>
Michal
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-09 15:45 ` Michal Marek
@ 2009-12-09 23:40 ` Rob Landley
2009-12-09 23:45 ` H. Peter Anvin
2009-12-10 13:52 ` Michal Marek
0 siblings, 2 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-09 23:40 UTC (permalink / raw)
To: Michal Marek; +Cc: linux-kernel, H. Peter Anvin, linux-kbuild
On Wednesday 09 December 2009 09:45:37 Michal Marek wrote:
> [CC hpa who wrote the timeconst.pl script]
>
> On 8.12.2009 10:19, Rob Landley wrote:
> > From: Rob Landley <rob@landley.net>
> >
> > Replace kernel/timeconst.pl with kernel/timeconst.sh. The new shell
> > script is much simpler, about 1/4 the size, and runs on Red Hat 9 from
> > 2003.
>
> I tried the shell script with the precomputed values in timeconst.pl and
> it gave me different results than the perl version for 250 and 1000:
You're right.
They're functionally equivalent (due to the relationship between MUL32 and
SHR32), which is why this code has worked for me and other people for a year
now. The difference is the possibility of an integer overflow if you try to
convert a time period of "0xffffffff".
Trivial fix:
--- a/sources/patches/linux-2.6.25-rc1-noperl.patch Tue Dec 08 20:22:53 2009
-0600
+++ b/sources/patches/linux-2.6.25-rc1-noperl.patch Wed Dec 09 17:28:26 2009
-0600
@@ -507,7 +507,7 @@
+
+ # Keep increasing $SHIFT until we've got 32 bits.
+
-+ [ $MUL32 -gt $(( 1 << 31 )) ] && break
++ [ $MUL32 -ge $(( 1 << 31 )) ] && break
+ SHIFT=$(( $SHIFT + 1 ))
+ done
+ MUL32=$( printf %x $MUL32 )
As long as MUL32 fits in 32 bits than you can multiply it by another 32 bit
number without overflow, and that's probably all the kernel's enforcing.
> #define HZ_TO_MSEC_NUM U64_C(4)
> #define HZ_TO_MSEC_DEN U64_C(1)
> -#define MSEC_TO_HZ_MUL32 U64_C(0x80000000)
> -#define MSEC_TO_HZ_ADJ32 U64_C(0x180000000)
> -#define MSEC_TO_HZ_SHR32 33
> +#define MSEC_TO_HZ_MUL32 U64_C(0x100000000)
> +#define MSEC_TO_HZ_ADJ32 U64_C(0x300000000)
> +#define MSEC_TO_HZ_SHR32 34
> #define MSEC_TO_HZ_NUM U64_C(1)
> #define MSEC_TO_HZ_DEN U64_C(4)
> #define HZ_TO_USEC_MUL32 U64_C(0xfa000000)
The same.
> and with HZ=1000:
> --- perl
> +++ bash
> @@ -8,14 +8,14 @@
> #error "kernel/timeconst.h has the wrong HZ value!"
> #endif
>
> -#define HZ_TO_MSEC_MUL32 U64_C(0x80000000)
> +#define HZ_TO_MSEC_MUL32 U64_C(0x100000000)
> #define HZ_TO_MSEC_ADJ32 U64_C(0x0)
> -#define HZ_TO_MSEC_SHR32 31
> +#define HZ_TO_MSEC_SHR32 32
And again.
> #define HZ_TO_MSEC_NUM U64_C(1)
> #define HZ_TO_MSEC_DEN U64_C(1)
> -#define MSEC_TO_HZ_MUL32 U64_C(0x80000000)
> +#define MSEC_TO_HZ_MUL32 U64_C(0x100000000)
> #define MSEC_TO_HZ_ADJ32 U64_C(0x0)
> -#define MSEC_TO_HZ_SHR32 31
> +#define MSEC_TO_HZ_SHR32 32
Same thing.
> You're trying to avoid the build dependency on Perl. What about adding a
> timeconst.h_shipped with the precomputed values from timeconst.pl:
Been there, done that. My first patch (way back for 2.6.25) took that
approach:
http://landley.net/hg/hgwebdir.cgi/firmware/file/a791ca629d9c/sources/patches/linux-2.6.25-
rc1-noperl.patch
But it turns out various non-x86 targets (such as ARM OMAP) allow HZ to be
specified by an entry field in the config file, into which the user can type a
range of numbers. See this post from last year for details:
http://lists.impactlinux.com/pipermail/firmware-impactlinux.com/2008-
December/000022.html
This is why reducing the perl version to just the precomputed constants
wouldn't work either. (They're there so that you only need to install a
random cpan library when surprised by a build break on non-x86 machines.)
> > + echo
> > + echo "#endif /* __KERNEL_TIMECHONST_H */"
>
> ^
>
> Should be "__KERNEL_TIMECONST_H".
Yeah, Joe Perches pointed that out to me off-list. It's just a comment so I
didn't resubmit the patch for that, but I've fixed my local version already.
Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-09 23:40 ` Rob Landley
@ 2009-12-09 23:45 ` H. Peter Anvin
2009-12-10 1:50 ` Rob Landley
2009-12-10 13:52 ` Michal Marek
1 sibling, 1 reply; 16+ messages in thread
From: H. Peter Anvin @ 2009-12-09 23:45 UTC (permalink / raw)
To: Rob Landley; +Cc: Michal Marek, linux-kernel, linux-kbuild
On 12/09/2009 03:40 PM, Rob Landley wrote:
>
> This is why reducing the perl version to just the precomputed constants
> wouldn't work either. (They're there so that you only need to install a
> random cpan library when surprised by a build break on non-x86 machines.)
>
It's not "a random CPAN library" - it's a core module.
-hpa
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-09 23:45 ` H. Peter Anvin
@ 2009-12-10 1:50 ` Rob Landley
2009-12-10 1:53 ` H. Peter Anvin
0 siblings, 1 reply; 16+ messages in thread
From: Rob Landley @ 2009-12-10 1:50 UTC (permalink / raw)
To: H. Peter Anvin; +Cc: Michal Marek, linux-kernel, linux-kbuild
On Wednesday 09 December 2009 17:45:21 H. Peter Anvin wrote:
> On 12/09/2009 03:40 PM, Rob Landley wrote:
> > This is why reducing the perl version to just the precomputed constants
> > wouldn't work either. (They're there so that you only need to install a
> > random cpan library when surprised by a build break on non-x86 machines.)
>
> It's not "a random CPAN library" - it's a core module.
Then why cache large quantities of its output and test for its existence?
Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-10 1:50 ` Rob Landley
@ 2009-12-10 1:53 ` H. Peter Anvin
0 siblings, 0 replies; 16+ messages in thread
From: H. Peter Anvin @ 2009-12-10 1:53 UTC (permalink / raw)
To: Rob Landley; +Cc: Michal Marek, linux-kernel, linux-kbuild
On 12/09/2009 05:50 PM, Rob Landley wrote:
> On Wednesday 09 December 2009 17:45:21 H. Peter Anvin wrote:
>> On 12/09/2009 03:40 PM, Rob Landley wrote:
>>> This is why reducing the perl version to just the precomputed constants
>>> wouldn't work either. (They're there so that you only need to install a
>>> random cpan library when surprised by a build break on non-x86 machines.)
>>
>> It's not "a random CPAN library" - it's a core module.
>
> Then why cache large quantities of its output and test for its existence?
>
To support archaic Perl versions and Perl binaries without libraries.
-hpa
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-09 23:40 ` Rob Landley
2009-12-09 23:45 ` H. Peter Anvin
@ 2009-12-10 13:52 ` Michal Marek
2009-12-10 23:16 ` Rob Landley
1 sibling, 1 reply; 16+ messages in thread
From: Michal Marek @ 2009-12-10 13:52 UTC (permalink / raw)
To: Rob Landley; +Cc: linux-kernel, H. Peter Anvin, linux-kbuild
On 10.12.2009 00:40, Rob Landley wrote:
> On Wednesday 09 December 2009 09:45:37 Michal Marek wrote:
>> You're trying to avoid the build dependency on Perl. What about adding a
>> timeconst.h_shipped with the precomputed values from timeconst.pl:
>
> Been there, done that. My first patch (way back for 2.6.25) took that
> approach:
>
> http://landley.net/hg/hgwebdir.cgi/firmware/file/a791ca629d9c/sources/patches/linux-2.6.25-
> rc1-noperl.patch
>
> But it turns out various non-x86 targets (such as ARM OMAP) allow HZ to be
> specified by an entry field in the config file, into which the user can type a
> range of numbers. See this post from last year for details:
>
> http://lists.impactlinux.com/pipermail/firmware-impactlinux.com/2008-
> December/000022.html
>
> This is why reducing the perl version to just the precomputed constants
> wouldn't work either. (They're there so that you only need to install a
> random cpan library when surprised by a build break on non-x86 machines.)
That's why I wrote
>> plus some makefile automagic to run the script iff the HZ value isn't
>> precomputed. Then you would only need Perl for exotic HZ configurations.
E.g. make it
...
#elif HZ == 1200
...
#else
#include "timeconst_custom.h"
#endif
and the makefile would run timeconst.pl to generate timeconst_custom.h
iff HZ is set to something arbitrary. I don't have a patch for that, but
I don't see a fundamental problem with such approach.
Michal
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-10 13:52 ` Michal Marek
@ 2009-12-10 23:16 ` Rob Landley
2009-12-11 15:31 ` Michal Marek
0 siblings, 1 reply; 16+ messages in thread
From: Rob Landley @ 2009-12-10 23:16 UTC (permalink / raw)
To: Michal Marek; +Cc: linux-kernel, H. Peter Anvin, linux-kbuild
On Thursday 10 December 2009 07:52:44 Michal Marek wrote:
> On 10.12.2009 00:40, Rob Landley wrote:
> > On Wednesday 09 December 2009 09:45:37 Michal Marek wrote:
> >> You're trying to avoid the build dependency on Perl. What about adding a
> >> timeconst.h_shipped with the precomputed values from timeconst.pl:
> >
> > Been there, done that. My first patch (way back for 2.6.25) took that
> > approach:
> >
> > http://landley.net/hg/hgwebdir.cgi/firmware/file/a791ca629d9c/sources/pat
> >ches/linux-2.6.25- rc1-noperl.patch
> >
> > But it turns out various non-x86 targets (such as ARM OMAP) allow HZ to
> > be specified by an entry field in the config file, into which the user
> > can type a range of numbers. See this post from last year for details:
> >
> > http://lists.impactlinux.com/pipermail/firmware-impactlinux.com/2008-
> > December/000022.html
> >
> > This is why reducing the perl version to just the precomputed constants
> > wouldn't work either. (They're there so that you only need to install a
> > random cpan library when surprised by a build break on non-x86 machines.)
>
> That's why I wrote
>
> >> plus some makefile automagic to run the script iff the HZ value isn't
> >> precomputed. Then you would only need Perl for exotic HZ configurations.
>
> E.g. make it
> ...
> #elif HZ == 1200
> ...
> #else
> #include "timeconst_custom.h"
> #endif
>
> and the makefile would run timeconst.pl to generate timeconst_custom.h
> iff HZ is set to something arbitrary. I don't have a patch for that, but
> I don't see a fundamental problem with such approach.
I looked at that when I was attempting to update (rather than replace) my
original patch. There's a reason I didn't go there. You're suggesting there
be two code paths, one maintained by hand and the other just about never
tested against bit-rot. You want to add logic to the makefile so it knows when
to run the perl script and when not to, meaning the makefile needs its own list
of the cached HZ values, which needs to be kept in sync with the header of
cached values, and thus the same information has to live in two places.
Meanwhile the shell script exists, works, and takes a fraction of a second to
run. Using it every build provides a single consistent code path which works
the same for everybody. I'm not seeing any advantage in cacheing values that
are easy to calculate at compile time. It's just as easy to completely
eliminate the perl dependency as to merely mitigate it.
> Michal
Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-10 23:16 ` Rob Landley
@ 2009-12-11 15:31 ` Michal Marek
2009-12-11 19:13 ` H. Peter Anvin
0 siblings, 1 reply; 16+ messages in thread
From: Michal Marek @ 2009-12-11 15:31 UTC (permalink / raw)
To: Rob Landley; +Cc: linux-kernel, H. Peter Anvin, linux-kbuild
Rob Landley wrote:
> On Thursday 10 December 2009 07:52:44 Michal Marek wrote:
>> and the makefile would run timeconst.pl to generate timeconst_custom.h
>> iff HZ is set to something arbitrary. I don't have a patch for that, but
>> I don't see a fundamental problem with such approach.
>
> I looked at that when I was attempting to update (rather than replace) my
> original patch. There's a reason I didn't go there. You're suggesting there
> be two code paths, one maintained by hand and the other just about never
> tested against bit-rot.
OK, that's valid point, indeed. Peter, would you ack Rob's patch with
the oneline fix added (http://lkml.org/lkml/2009/12/8/94 plus
http://lkml.org/lkml/2009/12/9/435)?
Michal
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-11 15:31 ` Michal Marek
@ 2009-12-11 19:13 ` H. Peter Anvin
2009-12-12 0:49 ` Rob Landley
0 siblings, 1 reply; 16+ messages in thread
From: H. Peter Anvin @ 2009-12-11 19:13 UTC (permalink / raw)
To: Michal Marek; +Cc: Rob Landley, linux-kernel, linux-kbuild
On 12/11/2009 07:31 AM, Michal Marek wrote:
>
> OK, that's valid point, indeed. Peter, would you ack Rob's patch with
> the oneline fix added (http://lkml.org/lkml/2009/12/8/94 plus
> http://lkml.org/lkml/2009/12/9/435)?
>
I strongly dislike his patch, as he open-codes specific multiprecision
arithmetic. This makes it hard for other people to maintain, and makes
it prone to errors -- as evidenced by the fact that it didn't even
replicate the known-good results.
I have made my position clear on this and other patches several times
before: I consider it a fool's errand, and a result of a completely
pointless crusade to make a particular science fair-type project a wee
bit easier. We have already seen real damage caused by it, since people
have used awk instead, and have gotten bitten by incompatibilities
between awk implementations.
As such, no, I will not ack this patch, and will consider myself
released of any obligation to maintain the code if this goes in anyway.
I would consider acking a C program which does proper multiprecision
arithmetic, but I'm also not going to spend my time on it.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh
2009-12-11 19:13 ` H. Peter Anvin
@ 2009-12-12 0:49 ` Rob Landley
0 siblings, 0 replies; 16+ messages in thread
From: Rob Landley @ 2009-12-12 0:49 UTC (permalink / raw)
To: H. Peter Anvin; +Cc: Michal Marek, linux-kernel, linux-kbuild
On Friday 11 December 2009 13:13:39 H. Peter Anvin wrote:
> On 12/11/2009 07:31 AM, Michal Marek wrote:
> > OK, that's valid point, indeed. Peter, would you ack Rob's patch with
> > the oneline fix added (http://lkml.org/lkml/2009/12/8/94 plus
> > http://lkml.org/lkml/2009/12/9/435)?
>
> I strongly dislike his patch, as he open-codes specific multiprecision
> arithmetic. This makes it hard for other people to maintain, and makes
> it prone to errors
It's always easier to understand code that you wrote, doubly so with perl.
The perl code this is replacing has comments, function names like fmul() and
fmuls() with no way to distinguish what they do except by reading their
implementation, and half of it is devoting to cacheing the output of the other
half for reasons which are never explained in the code.
The few comments the perl code does have are sometimes actually misleading.
For example, bignum_hex() has the comment "generate a hex value if the result
fits in 64 bits; otherwise skip". What would skpping mean in this context?
Would it silently emit a broken header, or would it break the build? (My first
guess is that "undef" without an expr would be a build break, but maybe this
is perl's way of saying "None"? I do know that whatever happened the result
wouldn't be a usable kernel, so "skip" is disingenous.)
That said, I read through and managed to understand the perl code. But it
took me more than a day, and I was motivated by the desire to replace it.
> -- as evidenced by the fact that it didn't even
> replicate the known-good results.
Actually I had noticed the difference back at the time I wrote the script, but
the value plus shift were functionally equivalent, and at the time (a year
ago) I vaguely recall working through the math (and looking at the kernel code
using the output) convinced me that that integer overflow couldn't actually
happen for real inputs. But I don't remember why (perhaps the value to be
converted is range checked somewhere so ffffffff couldn't actually make it to this
code, I don't remember) and thus my version would give more precision to the
result (which seemed to be the whole point of the exercise).
No point in trying to reconstruct my reasoning from a year ago when it's a one
line change to make it non-controversial, and the "value always fits in 32 bits
so you can safely multiply by an unsigned int due to LP64" is easier to
explain/document anyway. (On the other end of things, I do remember that the
admittedly insane HZ of ffffffff would have a GCD of 5 with 1000 and thus not be
saved as that. That came up because I was worried an ffffffff value times ffffffff
might _round_ up to overflow when adj32 was added. I did attempt to document
some of the edge cases in the shell script comments...)
> I have made my position clear on this and other patches several times
> before: I consider it a fool's errand,
I.E. your fundamental objection is to removing perl form the build.
You are the one who added this perl to the build system. You're also the one
who added perl to all the other projects you maintain (klibc and syslinux I
noticed) at approximately the same time, after years of those not requiring
perl. I don't know why you suddenly decided perl needed to be everywhere, but
the Linux kernel is not the only project you simultaneously applied this
philosophy to.
I strongly suspect the other objections you've raised in the past two years
are a proxy for the objection to removing perl. However, your central
objection to removing perl hasn't convinced people like Alan Cox, who called
Perl "a bad candidate for our toolchain dependencies" here:
http://lkml.indiana.edu/hypermail/linux/kernel/0901.1/02108.html
Thus you raise other issues, which seem to be proxies for that fundamental
objection. I've tried to address the ones that look like they were actually
intended to be addressed, but I note that your current objection is to the
something like the seventh submission of this patch, and I believe this is the
first time you've raised this particular issue. I believe I first submitted an
ancestor of this patch on February 15, 2008. Just this year I've submitted
previous versions of this patch (more or less in its current form) on January
2, 2009 (with a resubmit on January 3 in response to feedback), on June 22,
and on September 18. And again now. The patch hasn't changed much, your
objections to it have.
I don't even remember you previously complaining about the output differing.
(At a guess, you never actually tried my patch?) But it has been a while, I
could easily be forgetting details by now.
I'm posting these here because they're useful to other people, not because I
expect you to ever stop objecting to them no matter what changes I make.
You've made it clear you object to the _goal_ of the patch. The
implementation seems to be a side issue.
> and a result of a completely
> pointless crusade to make a particular science fair-type project a wee
> bit easier.
Embedded developers' desire to restrict their build environment to something
controllable seems to strike you as weird, yes. Would it help to explain that
it's the same general theory behind Linux From Scratch making a temporary
system, chrooting into it, and then building in there in Chapter 5?
Leaking random crap from the host is bad, often in subtle ways you don't
immediately catch. Some programs (perl, libtool, syscfg) are champions at
leaking context, and to be avoided if at all possible. (I suppose you could
always suggest setting up a different build environment for the kernel as for
userspace, the way Red Hat used to do with kgcc. Doesn't strike me as a good
idea, though.)
> We have already seen real damage caused by it, since people
> have used awk instead, and have gotten bitten by incompatibilities
> between awk implementations.
I'm not using AWK, and I'm sticking with POSIX shell constructs that were
there in susv3, let alone susv4.
Since I wasn't the one proposing any patches extensively using awk (I need the
man page open to make awk do anything more complicated than '{print $2}'), and
this patch isn't using awk at all, I guess you're once again objecting to the
removal of perl in general, not to the patch in front of you. And in doing
so, you're providing evidence that I'm not the only one motivated to submit
perl removal patches, which might undermine your "particular science fair
project" argument a bit.
I am motivated to follow up on this. I've been maintaining perl removal
patches for a couple years now because I personally need them, but I'm not the
only one using these patches, and I've been thanked for tackling this problem
by a dozen embedded developers. I wasn't the one who first noticed the perl
dependency when it went in back in .25, David Anders notified me of the issue
before I'd tested the -rc that introduced it. The most recent guy to say, and
I quote, "Thanks for eliminating the perl dependency." to me in private email
was Joe Perches (on Tuesday).
Embedded developers tend to do stuff off-list. This is because every new kernel
breaks random stuff on non-x86 targets. For example, I finally got powerpc's
pmac_zilog fixed a few days ago (allowing me to use the serial console on
qemu's mac99 target), after a thread stretching back two months (it broke
after 2.6.28). The "works for me" fix is here:
http://lists.ozlabs.org/pipermail/linuxppc-dev/2009-December/078700.html
The most recent arm breakage turned out to be simple (a new CONFIG_MMU symbol
showed up between 2.6.31 and 2.6.32 and needed to be switched on), but
diagnosing "it doesn't boot, no console messages" is always a pain.
The most recent mips breakage was fixed by commit
d71789b6fa37c21ce5eb588d279f57904a62e7e2 which I asked to be backported to
2.6.31 in the stable series and Greg KH acknowledged on November 5th. (I'd
link to my submission to stable@kernel.org but there's no entry for that in
vger lists and googling doesn't seem to come up with a public archive.)
That's just in the past month or so. Trying to git bisect each of those
problems found huge ranges of "it doesn't even compile" in the repository,
because that's the _norm_ for non-x86 targets during development.
Most embedded developers don't want to deal with this, so they stay a year or
three behind the bleeding edge and only upgrade after crazy people like me
have gotten it working. Since even the ones who _don't_ start their messages
by apologizing about their English know they'll be flamed or ignored if they
raise an issue about an 18 month old kernel here, they develop a fear of
posting on linux-kernel at all because it's an "unfriendly" place. (I try to
talk them out of it, but it's a cultural thing at this point. The new kernel
embedded list hasn't really helped more than 10% of this problem.)
I regularly tackle these issues anyway, am generally friendly to newbies on
the lists I follow, and apparently have no shame, so people sometimes forward
issues to me and hope I'll push them upstream so they don't have to. (And
then go away again once they've managed to upgrade to whatever snapshot
they'll be using for the next 3 years, leaving me to follow up.)
*shrug* I'm used to it. You feed stray issues patches and they wind up
adopting you...
> As such, no, I will not ack this patch, and will consider myself
> released of any obligation to maintain the code if this goes in anyway.
I've been maintaining this patch series for 2 years already. I would be happy
to maintain my changed version in future if it gets in. I expected that.
> I would consider acking a C program which does proper multiprecision
> arithmetic, but I'm also not going to spend my time on it.
Hmmm, "would consider acking" (not "would ack", not even "could ack"), with
the additional caveat that the multiprecision arithmetic must be an unspecified
"proper", whatever that means. The "proxy objections" thesis stated above
would label this an obvious delaying tactic, but if I promise to call your
bluff, then the current patch gets dropped on the floor for another development
cycle...
Well played, sir. I must plead the 5th for now.
> -hpa
Rob
--
Latency is more important than throughput. It's that simple. - Linus Torvalds
^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2009-12-12 0:49 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2009-12-08 9:17 [PATCH 0/3] clean out Perl from build system Rob Landley
2009-12-08 9:19 ` [PATCH 1/3] Replace kernel/timeconst.pl with kernel/timeconst.sh Rob Landley
2009-12-09 15:45 ` Michal Marek
2009-12-09 23:40 ` Rob Landley
2009-12-09 23:45 ` H. Peter Anvin
2009-12-10 1:50 ` Rob Landley
2009-12-10 1:53 ` H. Peter Anvin
2009-12-10 13:52 ` Michal Marek
2009-12-10 23:16 ` Rob Landley
2009-12-11 15:31 ` Michal Marek
2009-12-11 19:13 ` H. Peter Anvin
2009-12-12 0:49 ` Rob Landley
2009-12-08 9:21 ` [PATCH 2/3] Remove perl from make headers_install Rob Landley
2009-12-08 9:22 ` [PATCH 3/3] Convert kernel/cpu/mkcapflags.pl to kernel/cpu/mkcapflags.sh Rob Landley
2009-12-08 10:23 ` [PATCH 0/3] clean out Perl from build system Michal Marek
2009-12-08 15:08 ` Rob Landley
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