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authorH. Peter Anvin <hpa@zytor.com>2008-02-08 07:21:26 -0500
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-08 12:22:39 -0500
commitbdc807871d58285737d50dc6163d0feb72cb0dc2 (patch)
tree1a6d35f3537ed1a7460811549efd045ae97a0e6e
parent7ef3d2fd17c377ef64a2aa19677d17576606c3b4 (diff)
avoid overflows in kernel/time.c
When the conversion factor between jiffies and milli- or microseconds is not a single multiply or divide, as for the case of HZ == 300, we currently do a multiply followed by a divide. The intervening result, however, is subject to overflows, especially since the fraction is not simplified (for HZ == 300, we multiply by 300 and divide by 1000). This is exposed to the user when passing a large timeout to poll(), for example. This patch replaces the multiply-divide with a reciprocal multiplication on 32-bit platforms. When the input is an unsigned long, there is no portable way to do this on 64-bit platforms there is no portable way to do this since it requires a 128-bit intermediate result (which gcc does support on 64-bit platforms but may generate libgcc calls, e.g. on 64-bit s390), but since the output is a 32-bit integer in the cases affected, just simplify the multiply-divide (*3/10 instead of *300/1000). The reciprocal multiply used can have off-by-one errors in the upper half of the valid output range. This could be avoided at the expense of having to deal with a potential 65-bit intermediate result. Since the intent is to avoid overflow problems and most of the other time conversions are only semiexact, the off-by-one errors were considered an acceptable tradeoff. At Ralf Baechle's suggestion, this version uses a Perl script to compute the necessary constants. We already have dependencies on Perl for kernel compiles. This does, however, require the Perl module Math::BigInt, which is included in the standard Perl distribution starting with version 5.8.0. In order to support older versions of Perl, include a table of canned constants in the script itself, and structure the script so that Math::BigInt isn't required if pulling values from said table. Running the script requires that the HZ value is available from the Makefile. Thus, this patch also adds the Kconfig variable CONFIG_HZ to the architectures which didn't already have it (alpha, cris, frv, h8300, m32r, m68k, m68knommu, sparc, v850, and xtensa.) It does *not* touch the sh or sh64 architectures, since Paul Mundt has dealt with those separately in the sh tree. Signed-off-by: H. Peter Anvin <hpa@zytor.com> Cc: Ralf Baechle <ralf@linux-mips.org>, Cc: Sam Ravnborg <sam@ravnborg.org>, Cc: Paul Mundt <lethal@linux-sh.org>, Cc: Richard Henderson <rth@twiddle.net>, Cc: Michael Starvik <starvik@axis.com>, Cc: David Howells <dhowells@redhat.com>, Cc: Yoshinori Sato <ysato@users.sourceforge.jp>, Cc: Hirokazu Takata <takata@linux-m32r.org>, Cc: Geert Uytterhoeven <geert@linux-m68k.org>, Cc: Roman Zippel <zippel@linux-m68k.org>, Cc: William L. Irwin <sparclinux@vger.kernel.org>, Cc: Chris Zankel <chris@zankel.net>, Cc: H. Peter Anvin <hpa@zytor.com>, Cc: Jan Engelhardt <jengelh@computergmbh.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat
-rw-r--r--arch/alpha/Kconfig5
-rw-r--r--arch/cris/Kconfig4
-rw-r--r--arch/frv/Kconfig4
-rw-r--r--arch/h8300/Kconfig4
-rw-r--r--arch/m32r/Kconfig4
-rw-r--r--arch/m68k/Kconfig4
-rw-r--r--arch/m68knommu/Kconfig5
-rw-r--r--arch/sparc/Kconfig4
-rw-r--r--arch/v850/Kconfig7
-rw-r--r--arch/xtensa/Kconfig4
-rw-r--r--include/asm-alpha/param.h10
-rw-r--r--include/asm-cris/param.h2
-rw-r--r--include/asm-frv/param.h2
-rw-r--r--include/asm-h8300/param.h2
-rw-r--r--include/asm-m32r/param.h2
-rw-r--r--include/asm-m68k/param.h2
-rw-r--r--include/asm-m68knommu/param.h8
-rw-r--r--include/asm-sparc/param.h2
-rw-r--r--include/asm-v850/anna.h6
-rw-r--r--include/asm-v850/as85ep1.h6
-rw-r--r--include/asm-v850/fpga85e2c.h6
-rw-r--r--include/asm-v850/param.h3
-rw-r--r--include/asm-v850/rte_cb.h6
-rw-r--r--include/asm-v850/sim.h5
-rw-r--r--include/asm-v850/sim85e2.h6
-rw-r--r--include/asm-xtensa/param.h2
-rw-r--r--kernel/Makefile8
-rw-r--r--kernel/time.c29
-rw-r--r--kernel/timeconst.pl402
29 files changed, 486 insertions, 68 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index d9df913a464d..5b7dcd5a0e75 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -615,6 +615,11 @@ config VERBOSE_MCHECK_ON
615 615
616 Take the default (1) unless you want more control or more info. 616 Take the default (1) unless you want more control or more info.
617 617
618config HZ
619 int
620 default 1200 if ALPHA_RAWHIDE
621 default 1024
622
618source "drivers/pci/Kconfig" 623source "drivers/pci/Kconfig"
619source "drivers/eisa/Kconfig" 624source "drivers/eisa/Kconfig"
620 625
diff --git a/arch/cris/Kconfig b/arch/cris/Kconfig
index 27b082ac7f11..ff078e60e76d 100644
--- a/arch/cris/Kconfig
+++ b/arch/cris/Kconfig
@@ -55,6 +55,10 @@ config CRIS
55 bool 55 bool
56 default y 56 default y
57 57
58config HZ
59 int
60 default 100
61
58source "init/Kconfig" 62source "init/Kconfig"
59 63
60menu "General setup" 64menu "General setup"
diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 96f7d70f4473..9e561ede0925 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -57,6 +57,10 @@ config ARCH_HAS_ILOG2_U64
57 bool 57 bool
58 default y 58 default y
59 59
60config HZ
61 int
62 default 1000
63
60mainmenu "Fujitsu FR-V Kernel Configuration" 64mainmenu "Fujitsu FR-V Kernel Configuration"
61 65
62source "init/Kconfig" 66source "init/Kconfig"
diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
index b4ba4f8b505c..f69e5ea38558 100644
--- a/arch/h8300/Kconfig
+++ b/arch/h8300/Kconfig
@@ -82,6 +82,10 @@ config PCI
82 bool 82 bool
83 default n 83 default n
84 84
85config HZ
86 int
87 default 100
88
85source "init/Kconfig" 89source "init/Kconfig"
86 90
87source "arch/h8300/Kconfig.cpu" 91source "arch/h8300/Kconfig.cpu"
diff --git a/arch/m32r/Kconfig b/arch/m32r/Kconfig
index fe61e00a604f..d4679ab55b96 100644
--- a/arch/m32r/Kconfig
+++ b/arch/m32r/Kconfig
@@ -38,6 +38,10 @@ config NO_DMA
38config ARCH_SUPPORTS_AOUT 38config ARCH_SUPPORTS_AOUT
39 def_bool y 39 def_bool y
40 40
41config HZ
42 int
43 default 100
44
41source "init/Kconfig" 45source "init/Kconfig"
42 46
43 47
diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index bcbf3e4ee9d4..2b0ed89cd173 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -55,6 +55,10 @@ config NO_DMA
55config ARCH_SUPPORTS_AOUT 55config ARCH_SUPPORTS_AOUT
56 def_bool y 56 def_bool y
57 57
58config HZ
59 int
60 default 100
61
58mainmenu "Linux/68k Kernel Configuration" 62mainmenu "Linux/68k Kernel Configuration"
59 63
60source "init/Kconfig" 64source "init/Kconfig"
diff --git a/arch/m68knommu/Kconfig b/arch/m68knommu/Kconfig
index 24f732342d3e..548a7b321633 100644
--- a/arch/m68knommu/Kconfig
+++ b/arch/m68knommu/Kconfig
@@ -525,6 +525,11 @@ config 4KSTACKS
525 running more threads on a system and also reduces the pressure 525 running more threads on a system and also reduces the pressure
526 on the VM subsystem for higher order allocations. 526 on the VM subsystem for higher order allocations.
527 527
528config HZ
529 int
530 default 1000 if CLEOPATRA
531 default 100
532
528comment "RAM configuration" 533comment "RAM configuration"
529 534
530config RAMBASE 535config RAMBASE
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index 08821b078ecc..7c674a3503b6 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -30,6 +30,10 @@ config OF
30config ARCH_SUPPORTS_AOUT 30config ARCH_SUPPORTS_AOUT
31 def_bool y 31 def_bool y
32 32
33config HZ
34 int
35 default 100
36
33source "init/Kconfig" 37source "init/Kconfig"
34 38
35menu "General machine setup" 39menu "General machine setup"
diff --git a/arch/v850/Kconfig b/arch/v850/Kconfig
index 225f30d7cb32..7b6d3716efca 100644
--- a/arch/v850/Kconfig
+++ b/arch/v850/Kconfig
@@ -215,6 +215,13 @@ menu "Processor type and features"
215 bool 215 bool
216 default !V850E_CACHE && !V850E2_CACHE 216 default !V850E_CACHE && !V850E2_CACHE
217 217
218 # HZ depends on the platform
219 config HZ
220 int
221 default 24 if V850E_SIM || V850E2_SIM85E2
222 default 122 if V850E2_FPGA85E2C
223 default 100
224
218 #### Misc config 225 #### Misc config
219 226
220 config ROM_KERNEL 227 config ROM_KERNEL
diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
index 5d5546ce88fe..fd36764d7fb7 100644
--- a/arch/xtensa/Kconfig
+++ b/arch/xtensa/Kconfig
@@ -49,6 +49,10 @@ config ARCH_HAS_ILOG2_U64
49config NO_IOPORT 49config NO_IOPORT
50 def_bool y 50 def_bool y
51 51
52config HZ
53 int
54 default 100
55
52source "init/Kconfig" 56source "init/Kconfig"
53 57
54menu "Processor type and features" 58menu "Processor type and features"
diff --git a/include/asm-alpha/param.h b/include/asm-alpha/param.h
index 214e7996346f..0982f1d39499 100644
--- a/include/asm-alpha/param.h
+++ b/include/asm-alpha/param.h
@@ -5,15 +5,7 @@
5 hardware ignores reprogramming. We also need userland buy-in to the 5 hardware ignores reprogramming. We also need userland buy-in to the
6 change in HZ, since this is visible in the wait4 resources etc. */ 6 change in HZ, since this is visible in the wait4 resources etc. */
7 7
8 8#define HZ CONFIG_HZ
9#ifndef HZ
10# ifndef CONFIG_ALPHA_RAWHIDE
11# define HZ 1024
12# else
13# define HZ 1200
14# endif
15#endif
16
17#define USER_HZ HZ 9#define USER_HZ HZ
18 10
19#define EXEC_PAGESIZE 8192 11#define EXEC_PAGESIZE 8192
diff --git a/include/asm-cris/param.h b/include/asm-cris/param.h
index b24972639832..0e47994e40be 100644
--- a/include/asm-cris/param.h
+++ b/include/asm-cris/param.h
@@ -3,7 +3,7 @@
3 3
4/* Currently we assume that HZ=100 is good for CRIS. */ 4/* Currently we assume that HZ=100 is good for CRIS. */
5#ifdef __KERNEL__ 5#ifdef __KERNEL__
6# define HZ 100 /* Internal kernel timer frequency */ 6# define HZ CONFIG_HZ /* Internal kernel timer frequency */
7# define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 7# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
8# define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 8# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
9#endif 9#endif
diff --git a/include/asm-frv/param.h b/include/asm-frv/param.h
index 365653b1726c..6859dd503ed3 100644
--- a/include/asm-frv/param.h
+++ b/include/asm-frv/param.h
@@ -2,7 +2,7 @@
2#define _ASM_PARAM_H 2#define _ASM_PARAM_H
3 3
4#ifdef __KERNEL__ 4#ifdef __KERNEL__
5#define HZ 1000 /* Internal kernel timer frequency */ 5#define HZ CONFIG_HZ /* Internal kernel timer frequency */
6#define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 6#define USER_HZ 100 /* .. some user interfaces are in "ticks" */
7#define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 7#define CLOCKS_PER_SEC (USER_HZ) /* like times() */
8#endif 8#endif
diff --git a/include/asm-h8300/param.h b/include/asm-h8300/param.h
index c25806ed1fb3..04f64f100379 100644
--- a/include/asm-h8300/param.h
+++ b/include/asm-h8300/param.h
@@ -3,7 +3,7 @@
3 3
4 4
5#ifndef HZ 5#ifndef HZ
6#define HZ 100 6#define HZ CONFIG_HZ
7#endif 7#endif
8 8
9#ifdef __KERNEL__ 9#ifdef __KERNEL__
diff --git a/include/asm-m32r/param.h b/include/asm-m32r/param.h
index 3e14026e39cd..94c770196048 100644
--- a/include/asm-m32r/param.h
+++ b/include/asm-m32r/param.h
@@ -2,7 +2,7 @@
2#define _ASM_M32R_PARAM_H 2#define _ASM_M32R_PARAM_H
3 3
4#ifdef __KERNEL__ 4#ifdef __KERNEL__
5# define HZ 100 /* Internal kernel timer frequency */ 5# define HZ CONFIG_HZ /* Internal kernel timer frequency */
6# define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 6# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
7# define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 7# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
8#endif 8#endif
diff --git a/include/asm-m68k/param.h b/include/asm-m68k/param.h
index 60f409d81658..536a27888358 100644
--- a/include/asm-m68k/param.h
+++ b/include/asm-m68k/param.h
@@ -2,7 +2,7 @@
2#define _M68K_PARAM_H 2#define _M68K_PARAM_H
3 3
4#ifdef __KERNEL__ 4#ifdef __KERNEL__
5# define HZ 100 /* Internal kernel timer frequency */ 5# define HZ CONFIG_HZ /* Internal kernel timer frequency */
6# define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 6# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
7# define CLOCKS_PER_SEC (USER_HZ) /* like times() */ 7# define CLOCKS_PER_SEC (USER_HZ) /* like times() */
8#endif 8#endif
diff --git a/include/asm-m68knommu/param.h b/include/asm-m68knommu/param.h
index 4c9904d6512e..96c451018324 100644
--- a/include/asm-m68knommu/param.h
+++ b/include/asm-m68knommu/param.h
@@ -1,13 +1,7 @@
1#ifndef _M68KNOMMU_PARAM_H 1#ifndef _M68KNOMMU_PARAM_H
2#define _M68KNOMMU_PARAM_H 2#define _M68KNOMMU_PARAM_H
3 3
4 4#define HZ CONFIG_HZ
5#if defined(CONFIG_CLEOPATRA)
6#define HZ 1000
7#endif
8#ifndef HZ
9#define HZ 100
10#endif
11 5
12#ifdef __KERNEL__ 6#ifdef __KERNEL__
13#define USER_HZ HZ 7#define USER_HZ HZ
diff --git a/include/asm-sparc/param.h b/include/asm-sparc/param.h
index beaf02d364f2..86ba59af9d2c 100644
--- a/include/asm-sparc/param.h
+++ b/include/asm-sparc/param.h
@@ -3,7 +3,7 @@
3#define _ASMSPARC_PARAM_H 3#define _ASMSPARC_PARAM_H
4 4
5#ifdef __KERNEL__ 5#ifdef __KERNEL__
6# define HZ 100 /* Internal kernel timer frequency */ 6# define HZ CONFIG_HZ /* Internal kernel timer frequency */
7# define USER_HZ 100 /* .. some user interfaces are in "ticks" */ 7# define USER_HZ 100 /* .. some user interfaces are in "ticks" */
8# define CLOCKS_PER_SEC (USER_HZ) 8# define CLOCKS_PER_SEC (USER_HZ)
9#endif 9#endif
diff --git a/include/asm-v850/anna.h b/include/asm-v850/anna.h
index 3be77d5ecfce..cd5eaee103b0 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,
134#define V850E_TIMER_D_TMCD_CS_MIN 1 /* min 2^1 divider */ 134#define V850E_TIMER_D_TMCD_CS_MIN 1 /* min 2^1 divider */
135 135
136 136
137/* For <asm/param.h> */
138#ifndef HZ
139#define HZ 100
140#endif
141
142
143#endif /* __V850_ANNA_H__ */ 137#endif /* __V850_ANNA_H__ */
diff --git a/include/asm-v850/as85ep1.h b/include/asm-v850/as85ep1.h
index 659bc910ffd7..5a5ca9073d09 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,
149#define V850E_TIMER_D_TMCD_CS_MIN 2 /* min 2^2 divider */ 149#define V850E_TIMER_D_TMCD_CS_MIN 2 /* min 2^2 divider */
150 150
151 151
152/* For <asm/param.h> */
153#ifndef HZ
154#define HZ 100
155#endif
156
157
158#endif /* __V850_AS85EP1_H__ */ 152#endif /* __V850_AS85EP1_H__ */
diff --git a/include/asm-v850/fpga85e2c.h b/include/asm-v850/fpga85e2c.h
index d32f04504b13..23aae666c718 100644
--- a/include/asm-v850/fpga85e2c.h
+++ b/include/asm-v850/fpga85e2c.h
@@ -79,10 +79,4 @@ extern char _r0_ram;
79#endif 79#endif
80 80
81 81
82/* For <asm/param.h> */
83#ifndef HZ
84#define HZ 122 /* actually, 8.192ms ticks =~ 122.07 */
85#endif
86
87
88#endif /* __V850_FPGA85E2C_H__ */ 82#endif /* __V850_FPGA85E2C_H__ */
diff --git a/include/asm-v850/param.h b/include/asm-v850/param.h
index 3c65bd573782..281832690290 100644
--- a/include/asm-v850/param.h
+++ b/include/asm-v850/param.h
@@ -23,8 +23,7 @@
23#define MAXHOSTNAMELEN 64 /* max length of hostname */ 23#define MAXHOSTNAMELEN 64 /* max length of hostname */
24 24
25#ifdef __KERNEL__ 25#ifdef __KERNEL__
26#include <asm/machdep.h> /* For HZ */ 26# define HZ CONFIG_HZ
27
28# define USER_HZ 100 27# define USER_HZ 100
29# define CLOCKS_PER_SEC USER_HZ 28# define CLOCKS_PER_SEC USER_HZ
30#endif 29#endif
diff --git a/include/asm-v850/rte_cb.h b/include/asm-v850/rte_cb.h
index e85d261b79bf..db9879f00aa7 100644
--- a/include/asm-v850/rte_cb.h
+++ b/include/asm-v850/rte_cb.h
@@ -69,12 +69,6 @@
69#endif /* CONFIG_RTE_MB_A_PCI */ 69#endif /* CONFIG_RTE_MB_A_PCI */
70 70
71 71
72/* For <asm/param.h> */
73#ifndef HZ
74#define HZ 100
75#endif
76
77
78#ifndef __ASSEMBLY__ 72#ifndef __ASSEMBLY__
79extern void rte_cb_early_init (void); 73extern void rte_cb_early_init (void);
80extern void rte_cb_init_irqs (void); 74extern void rte_cb_init_irqs (void);
diff --git a/include/asm-v850/sim.h b/include/asm-v850/sim.h
index 10236abbe9be..026932d476cd 100644
--- a/include/asm-v850/sim.h
+++ b/include/asm-v850/sim.h
@@ -40,11 +40,6 @@
40#define R0_RAM_ADDR 0xFFFFF000 40#define R0_RAM_ADDR 0xFFFFF000
41 41
42 42
43/* For <asm/param.h> */
44#ifndef HZ
45#define HZ 24 /* Minimum supported frequency. */
46#endif
47
48/* For <asm/irq.h> */ 43/* For <asm/irq.h> */
49#define NUM_CPU_IRQS 6 44#define NUM_CPU_IRQS 6
50 45
diff --git a/include/asm-v850/sim85e2.h b/include/asm-v850/sim85e2.h
index 17dd4fa318e6..8b4d6974066c 100644
--- a/include/asm-v850/sim85e2.h
+++ b/include/asm-v850/sim85e2.h
@@ -66,10 +66,4 @@
66#define R0_RAM_ADDR 0xFFFFE000 66#define R0_RAM_ADDR 0xFFFFE000
67 67
68 68
69/* For <asm/param.h> */
70#ifndef HZ
71#define HZ 24 /* Minimum supported frequency. */
72#endif
73
74
75#endif /* __V850_SIM85E2_H__ */ 69#endif /* __V850_SIM85E2_H__ */
diff --git a/include/asm-xtensa/param.h b/include/asm-xtensa/param.h
index ce3a336cad07..82ad34d92d35 100644
--- a/include/asm-xtensa/param.h
+++ b/include/asm-xtensa/param.h
@@ -12,7 +12,7 @@
12#define _XTENSA_PARAM_H 12#define _XTENSA_PARAM_H
13 13
14#ifdef __KERNEL__ 14#ifdef __KERNEL__
15# define HZ 100 /* internal timer frequency */ 15# define HZ CONFIG_HZ /* internal timer frequency */
16# define USER_HZ 100 /* for user interfaces in "ticks" */ 16# define USER_HZ 100 /* for user interfaces in "ticks" */
17# define CLOCKS_PER_SEC (USER_HZ) /* frequnzy at which times() counts */ 17# define CLOCKS_PER_SEC (USER_HZ) /* frequnzy at which times() counts */
18#endif 18#endif
diff --git a/kernel/Makefile b/kernel/Makefile
index 60cd39c84e6d..6c584c55a6e9 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -91,3 +91,11 @@ quiet_cmd_ikconfiggz = IKCFG $@
91targets += config_data.h 91targets += config_data.h
92$(obj)/config_data.h: $(obj)/config_data.gz FORCE 92$(obj)/config_data.h: $(obj)/config_data.gz FORCE
93 $(call if_changed,ikconfiggz) 93 $(call if_changed,ikconfiggz)
94
95$(obj)/time.o: $(obj)/timeconst.h
96
97quiet_cmd_timeconst = TIMEC $@
98 cmd_timeconst = $(PERL) $< $(CONFIG_HZ) > $@
99targets += timeconst.h
100$(obj)/timeconst.h: $(src)/timeconst.pl FORCE
101 $(call if_changed,timeconst)
diff --git a/kernel/time.c b/kernel/time.c
index 3b705ecc3fb7..a5ec013b6c80 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -39,6 +39,8 @@
39#include <asm/uaccess.h> 39#include <asm/uaccess.h>
40#include <asm/unistd.h> 40#include <asm/unistd.h>
41 41
42#include "timeconst.h"
43
42/* 44/*
43 * The timezone where the local system is located. Used as a default by some 45 * The timezone where the local system is located. Used as a default by some
44 * programs who obtain this value by using gettimeofday. 46 * programs who obtain this value by using gettimeofday.
@@ -93,7 +95,8 @@ asmlinkage long sys_stime(time_t __user *tptr)
93 95
94#endif /* __ARCH_WANT_SYS_TIME */ 96#endif /* __ARCH_WANT_SYS_TIME */
95 97
96asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) 98asmlinkage long sys_gettimeofday(struct timeval __user *tv,
99 struct timezone __user *tz)
97{ 100{
98 if (likely(tv != NULL)) { 101 if (likely(tv != NULL)) {
99 struct timeval ktv; 102 struct timeval ktv;
@@ -118,7 +121,7 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __us
118 * hard to make the program warp the clock precisely n hours) or 121 * hard to make the program warp the clock precisely n hours) or
119 * compile in the timezone information into the kernel. Bad, bad.... 122 * compile in the timezone information into the kernel. Bad, bad....
120 * 123 *
121 * - TYT, 1992-01-01 124 * - TYT, 1992-01-01
122 * 125 *
123 * The best thing to do is to keep the CMOS clock in universal time (UTC) 126 * The best thing to do is to keep the CMOS clock in universal time (UTC)
124 * as real UNIX machines always do it. This avoids all headaches about 127 * as real UNIX machines always do it. This avoids all headaches about
@@ -240,7 +243,11 @@ unsigned int inline jiffies_to_msecs(const unsigned long j)
240#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) 243#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
241 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); 244 return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
242#else 245#else
243 return (j * MSEC_PER_SEC) / HZ; 246# if BITS_PER_LONG == 32
247 return ((u64)HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
248# else
249 return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
250# endif
244#endif 251#endif
245} 252}
246EXPORT_SYMBOL(jiffies_to_msecs); 253EXPORT_SYMBOL(jiffies_to_msecs);
@@ -252,7 +259,11 @@ unsigned int inline jiffies_to_usecs(const unsigned long j)
252#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) 259#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
253 return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC); 260 return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC);
254#else 261#else
255 return (j * USEC_PER_SEC) / HZ; 262# if BITS_PER_LONG == 32
263 return ((u64)HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
264# else
265 return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
266# endif
256#endif 267#endif
257} 268}
258EXPORT_SYMBOL(jiffies_to_usecs); 269EXPORT_SYMBOL(jiffies_to_usecs);
@@ -352,7 +363,7 @@ EXPORT_SYMBOL(mktime);
352 * normalize to the timespec storage format 363 * normalize to the timespec storage format
353 * 364 *
354 * Note: The tv_nsec part is always in the range of 365 * Note: The tv_nsec part is always in the range of
355 * 0 <= tv_nsec < NSEC_PER_SEC 366 * 0 <= tv_nsec < NSEC_PER_SEC
356 * For negative values only the tv_sec field is negative ! 367 * For negative values only the tv_sec field is negative !
357 */ 368 */
358void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec) 369void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec)
@@ -453,12 +464,13 @@ unsigned long msecs_to_jiffies(const unsigned int m)
453 /* 464 /*
454 * Generic case - multiply, round and divide. But first 465 * Generic case - multiply, round and divide. But first
455 * check that if we are doing a net multiplication, that 466 * check that if we are doing a net multiplication, that
456 * we wouldnt overflow: 467 * we wouldn't overflow:
457 */ 468 */
458 if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) 469 if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
459 return MAX_JIFFY_OFFSET; 470 return MAX_JIFFY_OFFSET;
460 471
461 return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC; 472 return ((u64)MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32)
473 >> MSEC_TO_HZ_SHR32;
462#endif 474#endif
463} 475}
464EXPORT_SYMBOL(msecs_to_jiffies); 476EXPORT_SYMBOL(msecs_to_jiffies);
@@ -472,7 +484,8 @@ unsigned long usecs_to_jiffies(const unsigned int u)
472#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) 484#elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC)
473 return u * (HZ / USEC_PER_SEC); 485 return u * (HZ / USEC_PER_SEC);
474#else 486#else
475 return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC; 487 return ((u64)USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32)
488 >> USEC_TO_HZ_SHR32;
476#endif 489#endif
477} 490}
478EXPORT_SYMBOL(usecs_to_jiffies); 491EXPORT_SYMBOL(usecs_to_jiffies);
diff --git a/kernel/timeconst.pl b/kernel/timeconst.pl
new file mode 100644
index 000000000000..62b1287932ed
--- /dev/null
+++ b/kernel/timeconst.pl
@@ -0,0 +1,402 @@
1#!/usr/bin/perl
2# -----------------------------------------------------------------------
3#
4# Copyright 2007 rPath, Inc. - All Rights Reserved
5#
6# This file is part of the Linux kernel, and is made available under
7# the terms of the GNU General Public License version 2 or (at your
8# option) any later version; incorporated herein by reference.
9#
10# -----------------------------------------------------------------------
11#
12
13#
14# Usage: timeconst.pl HZ > timeconst.h
15#
16
17# Precomputed values for systems without Math::BigInt
18# Generated by:
19# timeconst.pl --can 24 32 48 64 100 122 128 200 250 256 300 512 1000 1024 1200
20%canned_values = (
21 24 => [
22 '0xa6aaaaab','0x2aaaaaa',26,
23 '0xa6aaaaaaaaaaaaab','0x2aaaaaaaaaaaaaa',58,
24 125,3,
25 '0xc49ba5e4','0x1fbe76c8b4',37,
26 '0xc49ba5e353f7ceda','0x1fbe76c8b439581062',69,
27 3,125,
28 '0xa2c2aaab','0xaaaa',16,
29 '0xa2c2aaaaaaaaaaab','0xaaaaaaaaaaaa',48,
30 125000,3,
31 '0xc9539b89','0x7fffbce4217d',47,
32 '0xc9539b8887229e91','0x7fffbce4217d2849cb25',79,
33 3,125000,
34 ], 32 => [
35 '0xfa000000','0x6000000',27,
36 '0xfa00000000000000','0x600000000000000',59,
37 125,4,
38 '0x83126e98','0xfdf3b645a',36,
39 '0x83126e978d4fdf3c','0xfdf3b645a1cac0831',68,
40 4,125,
41 '0xf4240000','0x0',17,
42 '0xf424000000000000','0x0',49,
43 31250,1,
44 '0x8637bd06','0x3fff79c842fa',46,
45 '0x8637bd05af6c69b6','0x3fff79c842fa5093964a',78,
46 1,31250,
47 ], 48 => [
48 '0xa6aaaaab','0x6aaaaaa',27,
49 '0xa6aaaaaaaaaaaaab','0x6aaaaaaaaaaaaaa',59,
50 125,6,
51 '0xc49ba5e4','0xfdf3b645a',36,
52 '0xc49ba5e353f7ceda','0xfdf3b645a1cac0831',68,
53 6,125,
54 '0xa2c2aaab','0x15555',17,
55 '0xa2c2aaaaaaaaaaab','0x1555555555555',49,
56 62500,3,
57 '0xc9539b89','0x3fffbce4217d',46,
58 '0xc9539b8887229e91','0x3fffbce4217d2849cb25',78,
59 3,62500,
60 ], 64 => [
61 '0xfa000000','0xe000000',28,
62 '0xfa00000000000000','0xe00000000000000',60,
63 125,8,
64 '0x83126e98','0x7ef9db22d',35,
65 '0x83126e978d4fdf3c','0x7ef9db22d0e560418',67,
66 8,125,
67 '0xf4240000','0x0',18,
68 '0xf424000000000000','0x0',50,
69 15625,1,
70 '0x8637bd06','0x1fff79c842fa',45,
71 '0x8637bd05af6c69b6','0x1fff79c842fa5093964a',77,
72 1,15625,
73 ], 100 => [
74 '0xa0000000','0x0',28,
75 '0xa000000000000000','0x0',60,
76 10,1,
77 '0xcccccccd','0x733333333',35,
78 '0xcccccccccccccccd','0x73333333333333333',67,
79 1,10,
80 '0x9c400000','0x0',18,
81 '0x9c40000000000000','0x0',50,
82 10000,1,
83 '0xd1b71759','0x1fff2e48e8a7',45,
84 '0xd1b71758e219652c','0x1fff2e48e8a71de69ad4',77,
85 1,10000,
86 ], 122 => [
87 '0x8325c53f','0xfbcda3a',28,
88 '0x8325c53ef368eb05','0xfbcda3ac10c9714',60,
89 500,61,
90 '0xf9db22d1','0x7fbe76c8b',35,
91 '0xf9db22d0e560418a','0x7fbe76c8b43958106',67,
92 61,500,
93 '0x8012e2a0','0x3ef36',18,
94 '0x8012e29f79b47583','0x3ef368eb04325',50,
95 500000,61,
96 '0xffda4053','0x1ffffbce4217',45,
97 '0xffda4052d666a983','0x1ffffbce4217d2849cb2',77,
98 61,500000,
99 ], 128 => [
100 '0xfa000000','0x1e000000',29,
101 '0xfa00000000000000','0x1e00000000000000',61,
102 125,16,
103 '0x83126e98','0x3f7ced916',34,
104 '0x83126e978d4fdf3c','0x3f7ced916872b020c',66,
105 16,125,
106 '0xf4240000','0x40000',19,
107 '0xf424000000000000','0x4000000000000',51,
108 15625,2,
109 '0x8637bd06','0xfffbce4217d',44,
110 '0x8637bd05af6c69b6','0xfffbce4217d2849cb25',76,
111 2,15625,
112 ], 200 => [
113 '0xa0000000','0x0',29,
114 '0xa000000000000000','0x0',61,
115 5,1,
116 '0xcccccccd','0x333333333',34,
117 '0xcccccccccccccccd','0x33333333333333333',66,
118 1,5,
119 '0x9c400000','0x0',19,
120 '0x9c40000000000000','0x0',51,
121 5000,1,
122 '0xd1b71759','0xfff2e48e8a7',44,
123 '0xd1b71758e219652c','0xfff2e48e8a71de69ad4',76,
124 1,5000,
125 ], 250 => [
126 '0x80000000','0x0',29,
127 '0x8000000000000000','0x0',61,
128 4,1,
129 '0x80000000','0x180000000',33,
130 '0x8000000000000000','0x18000000000000000',65,
131 1,4,
132 '0xfa000000','0x0',20,
133 '0xfa00000000000000','0x0',52,
134 4000,1,
135 '0x83126e98','0x7ff7ced9168',43,
136 '0x83126e978d4fdf3c','0x7ff7ced916872b020c4',75,
137 1,4000,
138 ], 256 => [
139 '0xfa000000','0x3e000000',30,
140 '0xfa00000000000000','0x3e00000000000000',62,
141 125,32,
142 '0x83126e98','0x1fbe76c8b',33,
143 '0x83126e978d4fdf3c','0x1fbe76c8b43958106',65,
144 32,125,
145 '0xf4240000','0xc0000',20,
146 '0xf424000000000000','0xc000000000000',52,
147 15625,4,
148 '0x8637bd06','0x7ffde7210be',43,
149 '0x8637bd05af6c69b6','0x7ffde7210be9424e592',75,
150 4,15625,
151 ], 300 => [
152 '0xd5555556','0x2aaaaaaa',30,
153 '0xd555555555555556','0x2aaaaaaaaaaaaaaa',62,
154 10,3,
155 '0x9999999a','0x1cccccccc',33,
156 '0x999999999999999a','0x1cccccccccccccccc',65,
157 3,10,
158 '0xd0555556','0xaaaaa',20,
159 '0xd055555555555556','0xaaaaaaaaaaaaa',52,
160 10000,3,
161 '0x9d495183','0x7ffcb923a29',43,
162 '0x9d495182a9930be1','0x7ffcb923a29c779a6b5',75,
163 3,10000,
164 ], 512 => [
165 '0xfa000000','0x7e000000',31,
166 '0xfa00000000000000','0x7e00000000000000',63,
167 125,64,
168 '0x83126e98','0xfdf3b645',32,
169 '0x83126e978d4fdf3c','0xfdf3b645a1cac083',64,
170 64,125,
171 '0xf4240000','0x1c0000',21,
172 '0xf424000000000000','0x1c000000000000',53,
173 15625,8,
174 '0x8637bd06','0x3ffef39085f',42,
175 '0x8637bd05af6c69b6','0x3ffef39085f4a1272c9',74,
176 8,15625,
177 ], 1000 => [
178 '0x80000000','0x0',31,
179 '0x8000000000000000','0x0',63,
180 1,1,
181 '0x80000000','0x0',31,
182 '0x8000000000000000','0x0',63,
183 1,1,
184 '0xfa000000','0x0',22,
185 '0xfa00000000000000','0x0',54,
186 1000,1,
187 '0x83126e98','0x1ff7ced9168',41,
188 '0x83126e978d4fdf3c','0x1ff7ced916872b020c4',73,
189 1,1000,
190 ], 1024 => [
191 '0xfa000000','0xfe000000',32,
192 '0xfa00000000000000','0xfe00000000000000',64,
193 125,128,
194 '0x83126e98','0x7ef9db22',31,
195 '0x83126e978d4fdf3c','0x7ef9db22d0e56041',63,
196 128,125,
197 '0xf4240000','0x3c0000',22,
198 '0xf424000000000000','0x3c000000000000',54,
199 15625,16,
200 '0x8637bd06','0x1fff79c842f',41,
201 '0x8637bd05af6c69b6','0x1fff79c842fa5093964',73,
202 16,15625,
203 ], 1200 => [
204 '0xd5555556','0xd5555555',32,
205 '0xd555555555555556','0xd555555555555555',64,
206 5,6,
207 '0x9999999a','0x66666666',31,
208 '0x999999999999999a','0x6666666666666666',63,
209 6,5,
210 '0xd0555556','0x2aaaaa',22,
211 '0xd055555555555556','0x2aaaaaaaaaaaaa',54,
212 2500,3,
213 '0x9d495183','0x1ffcb923a29',41,
214 '0x9d495182a9930be1','0x1ffcb923a29c779a6b5',73,
215 3,2500,
216 ]
217);
218
219$has_bigint = eval 'use Math::BigInt qw(bgcd); 1;';
220
221sub bint($)
222{
223 my($x) = @_;
224 return Math::BigInt->new($x);
225}
226
227#
228# Constants for division by reciprocal multiplication.
229# (bits, numerator, denominator)
230#
231sub fmul($$$)
232{
233 my ($b,$n,$d) = @_;
234
235 $n = bint($n);
236 $d = bint($d);
237
238 return scalar (($n << $b)+$d-bint(1))/$d;
239}
240
241sub fadj($$$)
242{
243 my($b,$n,$d) = @_;
244
245 $n = bint($n);
246 $d = bint($d);
247
248 $d = $d/bgcd($n, $d);
249 return scalar (($d-bint(1)) << $b)/$d;
250}
251
252sub fmuls($$$) {
253 my($b,$n,$d) = @_;
254 my($s,$m);
255 my($thres) = bint(1) << ($b-1);
256
257 $n = bint($n);
258 $d = bint($d);
259
260 for ($s = 0; 1; $s++) {
261 $m = fmul($s,$n,$d);
262 return $s if ($m >= $thres);
263 }
264 return 0;
265}
266
267# Provides mul, adj, and shr factors for a specific
268# (bit, time, hz) combination
269sub muladj($$$) {
270 my($b, $t, $hz) = @_;
271 my $s = fmuls($b, $t, $hz);
272 my $m = fmul($s, $t, $hz);
273 my $a = fadj($s, $t, $hz);
274 return ($m->as_hex(), $a->as_hex(), $s);
275}
276
277# Provides numerator, denominator values
278sub numden($$) {
279 my($n, $d) = @_;
280 my $g = bgcd($n, $d);
281 return ($n/$g, $d/$g);
282}
283
284# All values for a specific (time, hz) combo
285sub conversions($$) {
286 my ($t, $hz) = @_;
287 my @val = ();
288
289 # HZ_TO_xx
290 push(@val, muladj(32, $t, $hz));
291 push(@val, muladj(64, $t, $hz));
292 push(@val, numden($t, $hz));
293
294 # xx_TO_HZ
295 push(@val, muladj(32, $hz, $t));
296 push(@val, muladj(64, $hz, $t));
297 push(@val, numden($hz, $t));
298
299 return @val;
300}
301
302sub compute_values($) {
303 my($hz) = @_;
304 my @val = ();
305 my $s, $m, $a, $g;
306
307 if (!$has_bigint) {
308 die "$0: HZ == $hz not canned and ".
309 "Math::BigInt not available\n";
310 }
311
312 # MSEC conversions
313 push(@val, conversions(1000, $hz));
314
315 # USEC conversions
316 push(@val, conversions(1000000, $hz));
317
318 return @val;
319}
320
321sub output($@)
322{
323 my($hz, @val) = @_;
324 my $pfx, $bit, $suf, $s, $m, $a;
325
326 print "/* Automatically generated by kernel/timeconst.pl */\n";
327 print "/* Conversion constants for HZ == $hz */\n";
328 print "\n";
329 print "#ifndef KERNEL_TIMECONST_H\n";
330 print "#define KERNEL_TIMECONST_H\n";
331 print "\n";
332
333 print "#include <linux/param.h>\n";
334
335 print "\n";
336 print "#if HZ != $hz\n";
337 print "#error \"kernel/timeconst.h has the wrong HZ value!\"\n";
338 print "#endif\n";
339 print "\n";
340
341 foreach $pfx ('HZ_TO_MSEC','MSEC_TO_HZ',
342 'USEC_TO_HZ','HZ_TO_USEC') {
343 foreach $bit (32, 64) {
344 foreach $suf ('MUL', 'ADJ', 'SHR') {
345 printf "#define %-23s %s\n",
346 "${pfx}_$suf$bit", shift(@val);
347 }
348 }
349 foreach $suf ('NUM', 'DEN') {
350 printf "#define %-23s %s\n",
351 "${pfx}_$suf", shift(@val);
352 }
353 }
354
355 print "\n";
356 print "#endif /* KERNEL_TIMECONST_H */\n";
357}
358
359($hz) = @ARGV;
360
361# Use this to generate the %canned_values structure
362if ($hz eq '--can') {
363 shift(@ARGV);
364 @hzlist = sort {$a <=> $b} (@ARGV);
365
366 print "# Precomputed values for systems without Math::BigInt\n";
367 print "# Generated by:\n";
368 print "# timeconst.pl --can ", join(' ', @hzlist), "\n";
369 print "\%canned_values = (\n";
370 my $pf = "\t";
371 foreach $hz (@hzlist) {
372 my @values = compute_values($hz);
373 print "$pf$hz => [\n";
374 while (scalar(@values)) {
375 my $bit;
376 foreach $bit (32, 64) {
377 my $m = shift(@values);
378 my $a = shift(@values);
379 my $s = shift(@values);
380 print "\t\t\'",$m,"\',\'",$a,"\',",$s,",\n";
381 }
382 my $n = shift(@values);
383 my $d = shift(@values);
384 print "\t\t",$n,',',$d,",\n";
385 }
386 print "\t]";
387 $pf = ', ';
388 }
389 print "\n);\n";
390} else {
391 $hz += 0; # Force to number
392 if ($hz < 1) {
393 die "Usage: $0 HZ\n";
394 }
395
396 @val = @{$canned_values{$hz}};
397 if (!defined(@val)) {
398 @val = compute_values($hz);
399 }
400 output($hz, @val);
401}
402exit 0;
generated by cgit v1.2.2 (git 2.25.0) at 2024-09-30 19:44:03 -0400