3 files changed, 120 insertions, 382 deletions

diff --git a/kernel/Makefile b/kernel/Makefile
index 6c072b6da239..ab1e0386bb2d 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -127,11 +127,19 @@ $(obj)/config_data.h: $(obj)/config_data.gz FORCE
 
 $(obj)/time.o: $(obj)/timeconst.h
 
-quiet_cmd_timeconst  = TIMEC   $@
-      cmd_timeconst  = $(PERL) $< $(CONFIG_HZ) > $@
+quiet_cmd_hzfile = HZFILE  $@
+      cmd_hzfile = echo "hz=$(CONFIG_HZ)" > $@
+
+targets += hz.bc
+$(obj)/hz.bc: $(objtree)/include/config/hz.h FORCE
+        $(call if_changed,hzfile)
+
+quiet_cmd_bc  = BC      $@
+      cmd_bc  = bc -q $(filter-out FORCE,$^) > $@
+
 targets += timeconst.h
-$(obj)/timeconst.h: $(src)/timeconst.pl FORCE
-        $(call if_changed,timeconst)
+$(obj)/timeconst.h: $(obj)/hz.bc $(src)/timeconst.bc FORCE
+        $(call if_changed,bc)
 
 ifeq ($(CONFIG_MODULE_SIG),y)
 #
diff --git a/kernel/timeconst.bc b/kernel/timeconst.bc
new file mode 100644
index 000000000000..511bdf2cafda
--- /dev/null
+++ b/kernel/timeconst.bc
@@ -0,0 +1,108 @@
+scale=0
+
+define gcd(a,b) {
+        auto t;
+        while (b) {
+                t = b;
+                b = a % b;
+                a = t;
+        }
+        return a;
+}
+
+/* Division by reciprocal multiplication. */
+define fmul(b,n,d) {
+       return (2^b*n+d-1)/d;
+}
+
+/* Adjustment factor when a ceiling value is used.  Use as:
+   (imul * n) + (fmulxx * n + fadjxx) >> xx) */
+define fadj(b,n,d) {
+        auto v;
+        d = d/gcd(n,d);
+        v = 2^b*(d-1)/d;
+        return v;
+}
+
+/* Compute the appropriate mul/adj values as well as a shift count,
+   which brings the mul value into the range 2^b-1 <= x < 2^b.  Such
+   a shift value will be correct in the signed integer range and off
+   by at most one in the upper half of the unsigned range. */
+define fmuls(b,n,d) {
+        auto s, m;
+        for (s = 0; 1; s++) {
+                m = fmul(s,n,d);
+                if (m >= 2^(b-1))
+                        return s;
+        }
+        return 0;
+}
+
+define timeconst(hz) {
+        print "/* Automatically generated by kernel/timeconst.bc */\n"
+        print "/* Time conversion constants for HZ == ", hz, " */\n"
+        print "\n"
+
+        print "#ifndef KERNEL_TIMECONST_H\n"
+        print "#define KERNEL_TIMECONST_H\n\n"
+
+        print "#include <linux/param.h>\n"
+        print "#include <linux/types.h>\n\n"
+
+        print "#if HZ != ", hz, "\n"
+        print "#error \qkernel/timeconst.h has the wrong HZ value!\q\n"
+        print "#endif\n\n"
+
+        if (hz < 2) {
+                print "#error Totally bogus HZ value!\n"
+        } else {
+                s=fmuls(32,1000,hz)
+                obase=16
+                print "#define HZ_TO_MSEC_MUL32\tU64_C(0x", fmul(s,1000,hz), ")\n"
+                print "#define HZ_TO_MSEC_ADJ32\tU64_C(0x", fadj(s,1000,hz), ")\n"
+                obase=10
+                print "#define HZ_TO_MSEC_SHR32\t", s, "\n"
+
+                s=fmuls(32,hz,1000)
+                obase=16
+                print "#define MSEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000), ")\n"
+                print "#define MSEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000), ")\n"
+                obase=10
+                print "#define MSEC_TO_HZ_SHR32\t", s, "\n"
+
+                obase=10
+                cd=gcd(hz,1000)
+                print "#define HZ_TO_MSEC_NUM\t\t", 1000/cd, "\n"
+                print "#define HZ_TO_MSEC_DEN\t\t", hz/cd, "\n"
+                print "#define MSEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+                print "#define MSEC_TO_HZ_DEN\t\t", 1000/cd, "\n"
+                print "\n"
+
+                s=fmuls(32,1000000,hz)
+                obase=16
+                print "#define HZ_TO_USEC_MUL32\tU64_C(0x", fmul(s,1000000,hz), ")\n"
+                print "#define HZ_TO_USEC_ADJ32\tU64_C(0x", fadj(s,1000000,hz), ")\n"
+                obase=10
+                print "#define HZ_TO_USEC_SHR32\t", s, "\n"
+
+                s=fmuls(32,hz,1000000)
+                obase=16
+                print "#define USEC_TO_HZ_MUL32\tU64_C(0x", fmul(s,hz,1000000), ")\n"
+                print "#define USEC_TO_HZ_ADJ32\tU64_C(0x", fadj(s,hz,1000000), ")\n"
+                obase=10
+                print "#define USEC_TO_HZ_SHR32\t", s, "\n"
+
+                obase=10
+                cd=gcd(hz,1000000)
+                print "#define HZ_TO_USEC_NUM\t\t", 1000000/cd, "\n"
+                print "#define HZ_TO_USEC_DEN\t\t", hz/cd, "\n"
+                print "#define USEC_TO_HZ_NUM\t\t", hz/cd, "\n"
+                print "#define USEC_TO_HZ_DEN\t\t", 1000000/cd, "\n"
+                print "\n"
+
+                print "#endif /* KERNEL_TIMECONST_H */\n"
+        }
+        halt
+}
+
+timeconst(hz)
diff --git a/kernel/timeconst.pl b/kernel/timeconst.pl
deleted file mode 100644
index eb51d76e058a..000000000000
--- a/kernel/timeconst.pl
+++ /dev/null
@@ -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;