[PATCH] Avoid overflows in kernel/time.c (version 4)

H. Peter Anvin
2007-12-17T23:54:29Z

h8300, m32r, m68k, m68knommu, sh64, sparc, v850, and xtensa.) It does
*not* resolve a weird case in the sh architecture, where HZ !=
CONFIG_HZ if CONFIG_SH_WDT is set. Paul Mundt has been contacted
about that, and has agreed to fix it up.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
Delta from previous version: indentation fixed in timeconst.pl

arch/alpha/Kconfig | 5 +
arch/cris/Kconfig | 4 +
arch/frv/Kconfig | 4 +
arch/h8300/Kconfig | 4 +
arch/m32r/Kconfig | 4 +
arch/m68k/Kconfig | 4 +
arch/m68knommu/Kconfig | 5 +
arch/sh64/Kconfig | 6 +
arch/sparc/Kconfig | 4 +
arch/v850/Kconfig | 7 +
arch/xtensa/Kconfig | 4 +
include/asm-alpha/param.h | 10 +-
include/asm-cris/param.h | 2 +-
include/asm-frv/param.h | 2 +-
include/asm-h8300/param.h | 2 +-
include/asm-m32r/param.h | 2 +-
include/asm-m68k/param.h | 2 +-
include/asm-m68knommu/param.h | 8 +-
include/asm-sh64/param.h | 6 +-
include/asm-sparc/param.h | 2 +-
include/asm-v850/anna.h | 6 -
include/asm-v850/as85ep1.h | 6 -
include/asm-v850/fpga85e2c.h | 6 -
include/asm-v850/param.h | 3 +-
include/asm-v850/rte_cb.h | 6 -
include/asm-v850/sim.h | 5 -
include/asm-v850/sim85e2.h | 6 -
include/asm-xtensa/param.h | 2 +-
kernel/Makefile | 8 +
kernel/time.c | 29 +++-
kernel/timeconst.pl | 340 +++++++++++++++++++++++++++++++++++++++++
31 files changed, 431 insertions(+), 73 deletions(-)
create mode 100644 kernel/timeconst.pl

diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index 4c002ba..442e4e7 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -616,6 +616,11 @@ config VERBOSE_MCHECK_ON

Take the default (1) unless you want more control or more info.

+config HZ
+ int
+ default 1200 if ALPHA_RAWHIDE
+ default 1024
+
source "drivers/pci/Kconfig"
source "drivers/eisa/Kconfig"

diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 222da15..fcc6a9e 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -55,6 +55,10 @@ config CRIS
bool
default y

+config HZ
+ int
+ default 100
+
source "init/Kconfig"

menu "General setup"
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 43153e7..57bdf2d 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -57,6 +57,10 @@ config ARCH_HAS_ILOG2_U64
bool
default y

+config HZ
+ int
+ default 1000
+
mainmenu "Fujitsu FR-V Kernel Configuration"

source "init/Kconfig"
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index ff6a871..8a40a6f 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -79,6 +79,10 @@ config PCI
bool
default n

+config HZ
+ int
+ default 100
+
source "init/Kconfig"

source "arch/h8300/Kconfig.cpu"
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index ab9a264..1547d81 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -34,6 +34,10 @@ config NO_IOPORT
config NO_DMA
def_bool y

+config HZ
+ int
+ default 100
+
source "init/Kconfig"

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 01dee84..06ccc89 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -52,6 +52,10 @@ config NO_IOPORT
config NO_DMA
def_bool SUN3

+config HZ
+ int
+ default 100
+
mainmenu "Linux/68k Kernel Configuration"

source "init/Kconfig"
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index f4b582c..da393c4 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -518,6 +518,11 @@ config 4KSTACKS
running more threads on a system and also reduces the pressure
on the VM subsystem for higher order allocations.

+config HZ
+ int
+ default 1000 if CLEOPATRA
+ default 100
+
comment "RAM configuration"

config RAMBASE
diff --git a/arch/sh64/Kconfig b/arch/sh64/Kconfig
index 6884d5a..95b76aa 100644
--- a/arch/sh64/Kconfig
+++ b/arch/sh64/Kconfig
@@ -293,3 +293,9 @@ source "security/Kconfig"
source "crypto/Kconfig"

source "lib/Kconfig"
+
+# Higher frequency needed for high-res WOVF
+config HZ
+ int
+ default 1000 if SH_WDT
+ default 100
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 527adc8..e2991f9 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -27,6 +27,10 @@ config ARCH_NO_VIRT_TO_BUS
config OF
def_bool y

+config HZ
+ int
+ default 100
+
source "init/Kconfig"

menu "General machine setup"
diff --git a/arch/v850/Kconfig b/arch/v850/Kconfig
index b6a50b8..b9c8b54 100644
--- a/arch/v850/Kconfig
+++ b/arch/v850/Kconfig
@@ -212,6 +212,13 @@ menu "Processor type and features"
bool
default !V850E_CACHE && !V850E2_CACHE

+ # HZ depends on the platform
+ config HZ
+ int
+ default 24 if V850E_SIM || V850E2_SIM85E2
+ default 122 if V850E2_FPGA85E2C
+ default 100
+
#### Misc config

config ROM_KERNEL
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index d3cb3d6..2a2aff1 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -49,6 +49,10 @@ config ARCH_HAS_ILOG2_U64
config NO_IOPORT
def_bool y

+config HZ
+ int
+ default 100
+
source "init/Kconfig"

menu "Processor type and features"
diff --git a/include/asm-alpha/param.h b/include/asm-alpha/param.h
index 214e799..0982f1d 100644
--- a/include/asm-alpha/param.h
+++ b/include/asm-alpha/param.h
@@ -5,15 +5,7 @@
hardware ignores reprogramming. We also need userland buy-in to the
change in HZ, since this is visible in the wait4 resources etc. */

-
-#ifndef HZ
-# ifndef CONFIG_ALPHA_RAWHIDE
-# define HZ 1024
-# else
-# define HZ 1200
-# endif
-#endif
-
+#define HZ CONFIG_HZ
#define USER_HZ HZ

#define EXEC_PAGESIZE 8192
diff --git a/include/asm-cris/param.h b/include/asm-cris/param.h
index b249726..0e47994 100644
--- a/include/asm-cris/param.h
+++ b/include/asm-cris/param.h
@@ -3,7 +3,7 @@

/* Currently we assume that HZ=100 is good for CRIS. */
#ifdef __KERNEL__
-# define HZ 100 /* Internal kernel timer frequency */
+# define HZ CONFIG_HZ /* Internal kernel timer frequency */
# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
#endif
diff --git a/include/asm-frv/param.h b/include/asm-frv/param.h
index 365653b..6859dd5 100644
--- a/include/asm-frv/param.h
+++ b/include/asm-frv/param.h
@@ -2,7 +2,7 @@
#define _ASM_PARAM_H

#ifdef __KERNEL__
-#define HZ 1000 /* Internal kernel timer frequency */
+#define HZ CONFIG_HZ /* Internal kernel timer frequency */
#define USER_HZ 100 /* .. some user interfaces are in "ticks" */
#define CLOCKS_PER_SEC (USER_HZ) /* like times() */
#endif
diff --git a/include/asm-h8300/param.h b/include/asm-h8300/param.h
index c25806e..04f64f1 100644
--- a/include/asm-h8300/param.h
+++ b/include/asm-h8300/param.h
@@ -3,7 +3,7 @@

#ifndef HZ
-#define HZ 100
+#define HZ CONFIG_HZ
#endif

#ifdef __KERNEL__
diff --git a/include/asm-m32r/param.h b/include/asm-m32r/param.h
index 3e14026..94c7701 100644
--- a/include/asm-m32r/param.h
+++ b/include/asm-m32r/param.h
@@ -2,7 +2,7 @@
#define _ASM_M32R_PARAM_H

#ifdef __KERNEL__
-# define HZ 100 /* Internal kernel timer frequency */
+# define HZ CONFIG_HZ /* Internal kernel timer frequency */
# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
#endif
diff --git a/include/asm-m68k/param.h b/include/asm-m68k/param.h
index 60f409d..536a278 100644
--- a/include/asm-m68k/param.h
+++ b/include/asm-m68k/param.h
@@ -2,7 +2,7 @@
#define _M68K_PARAM_H

#ifdef __KERNEL__
-# define HZ 100 /* Internal kernel timer frequency */
+# define HZ CONFIG_HZ /* Internal kernel timer frequency */
# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
#endif
diff --git a/include/asm-m68knommu/param.h b/include/asm-m68knommu/param.h
index 4c9904d..96c4510 100644
--- a/include/asm-m68knommu/param.h
+++ b/include/asm-m68knommu/param.h
@@ -1,13 +1,7 @@
#ifndef _M68KNOMMU_PARAM_H
#define _M68KNOMMU_PARAM_H

-
-#if defined(CONFIG_CLEOPATRA)
-#define HZ 1000
-#endif
-#ifndef HZ
-#define HZ 100
-#endif
+#define HZ CONFIG_HZ

#ifdef __KERNEL__
#define USER_HZ HZ
diff --git a/include/asm-sh64/param.h b/include/asm-sh64/param.h
index f409adb..4665154 100644
--- a/include/asm-sh64/param.h
+++ b/include/asm-sh64/param.h
@@ -14,11 +14,7 @@

#ifdef __KERNEL__
-# ifdef CONFIG_SH_WDT
-# define HZ 1000 /* Needed for high-res WOVF */
-# else
-# define HZ 100
-# endif
+# define HZ CONFIG_HZ
# define USER_HZ 100 /* User interfaces are in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ) /* frequency at which times() counts */
#endif
diff --git a/include/asm-sparc/param.h b/include/asm-sparc/param.h
index beaf02d..86ba59a 100644
--- a/include/asm-sparc/param.h
+++ b/include/asm-sparc/param.h
@@ -3,7 +3,7 @@
#define _ASMSPARC_PARAM_H

#ifdef __KERNEL__
-# define HZ 100 /* Internal kernel timer frequency */
+# define HZ CONFIG_HZ /* Internal kernel timer frequency */
# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ)
#endif
diff --git a/include/asm-v850/anna.h b/include/asm-v850/anna.h
index 3be77d5..cd5eaee 100644
--- a/include/asm-v850/anna.h
+++ b/include/asm-v850/anna.h
@@ -134,10 +134,4 @@ extern void anna_uart_pre_configure (unsigned chan,
#define V850E_TIMER_D_TMCD_CS_MIN 1 /* min 2^1 divider */

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 100
-#endif
-
-
#endif /* __V850_ANNA_H__ */
diff --git a/include/asm-v850/as85ep1.h b/include/asm-v850/as85ep1.h
index 659bc91..5a5ca90 100644
--- a/include/asm-v850/as85ep1.h
+++ b/include/asm-v850/as85ep1.h
@@ -149,10 +149,4 @@ extern void as85ep1_uart_pre_configure (unsigned chan,
#define V850E_TIMER_D_TMCD_CS_MIN 2 /* min 2^2 divider */

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 100
-#endif
-
-
#endif /* __V850_AS85EP1_H__ */
diff --git a/include/asm-v850/fpga85e2c.h b/include/asm-v850/fpga85e2c.h
index d32f045..23aae66 100644
--- a/include/asm-v850/fpga85e2c.h
+++ b/include/asm-v850/fpga85e2c.h
@@ -79,10 +79,4 @@ extern char _r0_ram;
#endif

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 122 /* actually, 8.192ms ticks =~ 122.07 */
-#endif
-
-
#endif /* __V850_FPGA85E2C_H__ */
diff --git a/include/asm-v850/param.h b/include/asm-v850/param.h
index 3c65bd5..2818326 100644
--- a/include/asm-v850/param.h
+++ b/include/asm-v850/param.h
@@ -23,8 +23,7 @@
#define MAXHOSTNAMELEN 64 /* max length of hostname */

#ifdef __KERNEL__
-#include <asm/machdep.h> /* For HZ */
-
+# define HZ CONFIG_HZ
# define USER_HZ 100
# define CLOCKS_PER_SEC USER_HZ
#endif
diff --git a/include/asm-v850/rte_cb.h b/include/asm-v850/rte_cb.h
index e85d261..db9879f 100644
--- a/include/asm-v850/rte_cb.h
+++ b/include/asm-v850/rte_cb.h
@@ -69,12 +69,6 @@
#endif /* CONFIG_RTE_MB_A_PCI */

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 100
-#endif
-
-
#ifndef __ASSEMBLY__
extern void rte_cb_early_init (void);
extern void rte_cb_init_irqs (void);
diff --git a/include/asm-v850/sim.h b/include/asm-v850/sim.h
index 10236ab..026932d 100644
--- a/include/asm-v850/sim.h
+++ b/include/asm-v850/sim.h
@@ -40,11 +40,6 @@
#define R0_RAM_ADDR 0xFFFFF000

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 24 /* Minimum supported frequency. */
-#endif
-
/* For <asm/irq.h> */
#define NUM_CPU_IRQS 6

diff --git a/include/asm-v850/sim85e2.h b/include/asm-v850/sim85e2.h
index 17dd4fa..8b4d697 100644
--- a/include/asm-v850/sim85e2.h
+++ b/include/asm-v850/sim85e2.h
@@ -66,10 +66,4 @@
#define R0_RAM_ADDR 0xFFFFE000

-/* For <asm/param.h> */
-#ifndef HZ
-#define HZ 24 /* Minimum supported frequency. */
-#endif
-
-
#endif /* __V850_SIM85E2_H__ */
diff --git a/include/asm-xtensa/param.h b/include/asm-xtensa/param.h
index ce3a336..82ad34d 100644
--- a/include/asm-xtensa/param.h
+++ b/include/asm-xtensa/param.h
@@ -12,7 +12,7 @@
#define _XTENSA_PARAM_H

#ifdef __KERNEL__
-# define HZ 100 /* internal timer frequency */
+# define HZ CONFIG_HZ /* internal timer frequency */
# define USER_HZ 100 /* for user interfaces in "ticks" */
# define CLOCKS_PER_SEC (USER_HZ) /* frequnzy at which times() counts */
#endif
diff --git a/kernel/Makefile b/kernel/Makefile
index dfa9695..749825a 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -80,3 +80,11 @@ quiet_cmd_ikconfiggz = IKCFG $@
targets += config_data.h
$(obj)/config_data.h: $(obj)/config_data.gz FORCE
$(call if_changed,ikconfiggz)
+
+$(obj)/time.o: $(obj)/timeconst.h
+
+quiet_cmd_timeconst = TIMEC $@
+ cmd_timeconst = $(PERL) $< $(CONFIG_HZ) > $@
+targets += timeconst.h
+$(obj)/timeconst.h: $(src)/timeconst.pl $(wildcard include/config/hz.h) FORCE
+ $(call if_changed,timeconst)
diff --git a/kernel/time.c b/kernel/time.c
index 09d3c45..8e790b5 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -39,6 +39,8 @@
#include <asm/uaccess.h>
#include <asm/unistd.h>

+#include "timeconst.h"
+
/*
* The timezone where the local system is located. Used as a default by some
* programs who obtain this value by using gettimeofday.
@@ -93,7 +95,8 @@ asmlinkage long sys_stime(time_t __user *tptr)

#endif /* __ARCH_WANT_SYS_TIME */

-asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz)
+asmlinkage long sys_gettimeofday(struct timeval __user *tv,
+ struct timezone __user *tz)
{
if (likely(tv != NULL)) {
struct timeval ktv;
@@ -118,7 +121,7 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __us
* hard to make the program warp the clock precisely n hours) or
* compile in the timezone information into the kernel. Bad, bad....
*
- * - TYT, 1992-01-01
+ * - TYT, 1992-01-01
*
* The best thing to do is to keep the CMOS clock in universal time (UTC)
* as real UNIX machines always do it. This avoids all headaches about
@@ -239,7 +242,11 @@ unsigned int inline jiffies_to_msecs(const unsigned long j)
#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
#else
- return (j * MSEC_PER_SEC) / HZ;
+# if BITS_PER_LONG == 32
+ return ((u64)HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
+# else
+ return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
+# endif
#endif
}
EXPORT_SYMBOL(jiffies_to_msecs);
@@ -251,7 +258,11 @@ unsigned int inline jiffies_to_usecs(const unsigned long j)
#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
#else
- return (j * USEC_PER_SEC) / HZ;
+# if BITS_PER_LONG == 32
+ return ((u64)HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
+# else
+ return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
+# endif
#endif
}
EXPORT_SYMBOL(jiffies_to_usecs);
@@ -351,7 +362,7 @@ EXPORT_SYMBOL(mktime);
* normalize to the timespec storage format
*
* Note: The tv_nsec part is always in the range of
- * 0 <= tv_nsec < NSEC_PER_SEC
+ * 0 <= tv_nsec < NSEC_PER_SEC
* For negative values only the tv_sec field is negative !
*/
void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
@@ -452,12 +463,13 @@ unsigned long msecs_to_jiffies(const unsigned int m)
/*
* Generic case - multiply, round and divide. But first
* check that if we are doing a net multiplication, that
- * we wouldnt overflow:
+ * we wouldn't overflow:
*/
if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
return MAX_JIFFY_OFFSET;

- return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC;
+ return ((u64)MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
+ >> MSEC_TO_HZ_SHR32;
#endif
}
EXPORT_SYMBOL(msecs_to_jiffies);
@@ -471,7 +483,8 @@ unsigned long usecs_to_jiffies(const unsigned int u)
#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
return u * (HZ / USEC_PER_SEC);
#else
- return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC;
+ return ((u64)USEC_TO_HZ_MUL32 * m + USEC_TO_HZ_ADJ32)
+ >> USEC_TO_HZ_SHR32;
#endif
}
EXPORT_SYMBOL(usecs_to_jiffies);
diff --git a/kernel/timeconst.pl b/kernel/timeconst.pl
new file mode 100644
index 0000000..42572e3
--- /dev/null
+++ b/kernel/timeconst.pl
@@ -0,0 +1,340 @@
+#!/usr/bin/perl
+# -----------------------------------------------------------------------
+#
+# Copyright 2007 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,
+ '0xa6aaaaaaaaaaaaab','0x2aaaaaaaaaaaaaa',58,
+ '0xc49ba5e4','0x1fbe76c8b4',37,
+ '0xc49ba5e353f7ceda','0x1fbe76c8b439581062',69,
+ '0xa2c2aaab','0xaaaa',16,
+ '0xa2c2aaaaaaaaaaab','0xaaaaaaaaaaaa',48,
+ '0xc9539b89','0x7fffbce4217d',47,
+ '0xc9539b8887229e91','0x7fffbce4217d2849cb25',79,
+ ], 32 => [
+ '0xfa000000','0x6000000',27,
+ '0xfa00000000000000','0x600000000000000',59,
+ '0x83126e98','0xfdf3b645a',36,
+ '0x83126e978d4fdf3c','0xfdf3b645a1cac0831',68,
+ '0xf4240000','0x0',17,
+ '0xf424000000000000','0x0',49,
+ '0x8637bd06','0x3fff79c842fa',46,
+ '0x8637bd05af6c69b6','0x3fff79c842fa5093964a',78,
+ ], 48 => [
+ '0xa6aaaaab','0x6aaaaaa',27,
+ '0xa6aaaaaaaaaaaaab','0x6aaaaaaaaaaaaaa',59,
+ '0xc49ba5e4','0xfdf3b645a',36,
+ '0xc49ba5e353f7ceda','0xfdf3b645a1cac0831',68,
+ '0xa2c2aaab','0x15555',17,
+ '0xa2c2aaaaaaaaaaab','0x1555555555555',49,
+ '0xc9539b89','0x3fffbce4217d',46,
+ '0xc9539b8887229e91','0x3fffbce4217d2849cb25',78,
+ ], 64 => [
+ '0xfa000000','0xe000000',28,
+ '0xfa00000000000000','0xe00000000000000',60,
+ '0x83126e98','0x7ef9db22d',35,
+ '0x83126e978d4fdf3c','0x7ef9db22d0e560418',67,
+ '0xf4240000','0x0',18,
+ '0xf424000000000000','0x0',50,
+ '0x8637bd06','0x1fff79c842fa',45,
+ '0x8637bd05af6c69b6','0x1fff79c842fa5093964a',77,
+ ], 100 => [
+ '0xa0000000','0x0',28,
+ '0xa000000000000000','0x0',60,
+ '0xcccccccd','0x733333333',35,
+ '0xcccccccccccccccd','0x73333333333333333',67,
+ '0x9c400000','0x0',18,
+ '0x9c40000000000000','0x0',50,
+ '0xd1b71759','0x1fff2e48e8a7',45,
+ '0xd1b71758e219652c','0x1fff2e48e8a71de69ad4',77,
+ ], 122 => [
+ '0x8325c53f','0xfbcda3a',28,
+ '0x8325c53ef368eb05','0xfbcda3ac10c9714',60,
+ '0xf9db22d1','0x7fbe76c8b',35,
+ '0xf9db22d0e560418a','0x7fbe76c8b43958106',67,
+ '0x8012e2a0','0x3ef36',18,
+ '0x8012e29f79b47583','0x3ef368eb04325',50,
+ '0xffda4053','0x1ffffbce4217',45,
+ '0xffda4052d666a983','0x1ffffbce4217d2849cb2',77,
+ ], 128 => [
+ '0xfa000000','0x1e000000',29,
+ '0xfa00000000000000','0x1e00000000000000',61,
+ '0x83126e98','0x3f7ced916',34,
+ '0x83126e978d4fdf3c','0x3f7ced916872b020c',66,
+ '0xf4240000','0x40000',19,
+ '0xf424000000000000','0x4000000000000',51,
+ '0x8637bd06','0xfffbce4217d',44,
+ '0x8637bd05af6c69b6','0xfffbce4217d2849cb25',76,
+ ], 200 => [
+ '0xa0000000','0x0',29,
+ '0xa000000000000000','0x0',61,
+ '0xcccccccd','0x333333333',34,
+ '0xcccccccccccccccd','0x33333333333333333',66,
+ '0x9c400000','0x0',19,
+ '0x9c40000000000000','0x0',51,
+ '0xd1b71759','0xfff2e48e8a7',44,
+ '0xd1b71758e219652c','0xfff2e48e8a71de69ad4',76,
+ ], 250 => [
+ '0x80000000','0x0',29,
+ '0x8000000000000000','0x0',61,
+ '0x80000000','0x180000000',33,
+ '0x8000000000000000','0x18000000000000000',65,
+ '0xfa000000','0x0',20,
+ '0xfa00000000000000','0x0',52,
+ '0x83126e98','0x7ff7ced9168',43,
+ '0x83126e978d4fdf3c','0x7ff7ced916872b020c4',75,
+ ], 256 => [
+ '0xfa000000','0x3e000000',30,
+ '0xfa00000000000000','0x3e00000000000000',62,
+ '0x83126e98','0x1fbe76c8b',33,
+ '0x83126e978d4fdf3c','0x1fbe76c8b43958106',65,
+ '0xf4240000','0xc0000',20,
+ '0xf424000000000000','0xc000000000000',52,
+ '0x8637bd06','0x7ffde7210be',43,
+ '0x8637bd05af6c69b6','0x7ffde7210be9424e592',75,
+ ], 300 => [
+ '0xd5555556','0x2aaaaaaa',30,
+ '0xd555555555555556','0x2aaaaaaaaaaaaaaa',62,
+ '0x9999999a','0x1cccccccc',33,
+ '0x999999999999999a','0x1cccccccccccccccc',65,
+ '0xd0555556','0xaaaaa',20,
+ '0xd055555555555556','0xaaaaaaaaaaaaa',52,
+ '0x9d495183','0x7ffcb923a29',43,
+ '0x9d495182a9930be1','0x7ffcb923a29c779a6b5',75,
+ ], 512 => [
+ '0xfa000000','0x7e000000',31,
+ '0xfa00000000000000','0x7e00000000000000',63,
+ '0x83126e98','0xfdf3b645',32,
+ '0x83126e978d4fdf3c','0xfdf3b645a1cac083',64,
+ '0xf4240000','0x1c0000',21,
+ '0xf424000000000000','0x1c000000000000',53,
+ '0x8637bd06','0x3ffef39085f',42,
+ '0x8637bd05af6c69b6','0x3ffef39085f4a1272c9',74,
+ ], 1000 => [
+ '0x80000000','0x0',31,
+ '0x8000000000000000','0x0',63,
+ '0x80000000','0x0',31,
+ '0x8000000000000000','0x0',63,
+ '0xfa000000','0x0',22,
+ '0xfa00000000000000','0x0',54,
+ '0x83126e98','0x1ff7ced9168',41,
+ '0x83126e978d4fdf3c','0x1ff7ced916872b020c4',73,
+ ], 1024 => [
+ '0xfa000000','0xfe000000',32,
+ '0xfa00000000000000','0xfe00000000000000',64,
+ '0x83126e98','0x7ef9db22',31,
+ '0x83126e978d4fdf3c','0x7ef9db22d0e56041',63,
+ '0xf4240000','0x3c0000',22,
+ '0xf424000000000000','0x3c000000000000',54,
+ '0x8637bd06','0x1fff79c842f',41,
+ '0x8637bd05af6c69b6','0x1fff79c842fa5093964',73,
+ ], 1200 => [
+ '0xd5555556','0xd5555555',32,
+ '0xd555555555555556','0xd555555555555555',64,
+ '0x9999999a','0x66666666',31,
+ '0x999999999999999a','0x6666666666666666',63,
+ '0xd0555556','0x2aaaaa',22,
+ '0xd055555555555556','0x2aaaaaaaaaaaaa',54,
+ '0x9d495183','0x1ffcb923a29',41,
+ '0x9d495182a9930be1','0x1ffcb923a29c779a6b5',73,
+ ]
+);
+
+$has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';
+
+sub bint($)
+{
+ 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 >= $thres);
+ }
+ return 0;
+}
+
+sub compute_values($) {
+ my($hz) = @_;
+ my @val = ();
+ my $s, $m, $a;
+
+ if (!$has_bigint) {
+ die "$0: HZ == $hz not canned and ".
+ "Math::BigInt not available\n";
+ }
+
+ # HZ_TO_MSEC_*32
+ $s = fmuls(32, 1000, $hz);
+ $m = fmul($s, 1000, $hz);
+ $a = fadj($s, 1000, $hz);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # HZ_TO_MSEC_*64
+ $s = fmuls(64, 1000, $hz);
+ $m = fmul($s, 1000, $hz);
+ $a = fadj($s, 1000, $hz);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # MSEC_TO_HZ_*32
+ $s = fmuls(32, $hz, 1000);
+ $m = fmul($s, $hz, 1000);
+ $a = fadj($s, $hz, 1000);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # MSEC_TO_HZ_*64
+ $s = fmuls(64, $hz, 1000);
+ $m = fmul($s, $hz, 1000);
+ $a = fadj($s, $hz, 1000);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # HZ_TO_USEC_*32
+ $s = fmuls(32, 1000000, $hz);
+ $m = fmul($s, 1000000, $hz);
+ $a = fadj($s, 1000000, $hz);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # HZ_TO_USEC_*64
+ $s = fmuls(64, 1000000, $hz);
+ $m = fmul($s, 1000000, $hz);
+ $a = fadj($s, 1000000, $hz);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # USEC_TO_HZ_*32
+ $s = fmuls(32, $hz, 1000000);
+ $m = fmul($s, $hz, 1000000);
+ $a = fadj($s, $hz, 1000000);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ # USEC_TO_HZ_*64
+ $s = fmuls(64, $hz, 1000000);
+ $m = fmul($s, $hz, 1000000);
+ $a = fadj($s, $hz, 1000000);
+ push(@val, $m->as_hex(), $a->as_hex(), $s);
+
+ return @val;
+}
+
+sub output($@)
+{
+ 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 "\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',
+ 'USEC_TO_HZ','HZ_TO_USEC') {
+ foreach $bit (32, 64) {
+ foreach $suf ('MUL', 'ADJ', 'SHR') {
+ printf "#define %-23s %s\n",
+ "${pfx}_$suf$bit", shift(@val);
+ }
+ }
+ }
+
+ print "\n";
+ print "#endif /* KERNEL_TIMECONST_H */\n";
+}
+
+($hz) = @ARGV;
+
+# Use this to generate the %canned_values structure
+if ($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 $m = shift(@values);
+ my $a = shift(@values);
+ my $s = shift(@values);
+ print "\t\t\'",$m,"\',\'",$a,"\',",$s,",\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;
--
1.5.3.4