linux/arch/sparc/Kconfig

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# For a description of the syntax of this configuration file,
# see Documentation/kbuild/kconfig-language.txt.
#
mainmenu "Linux/SPARC Kernel Configuration"
config MMU
bool
default y
config HIGHMEM
bool
default y
config ZONE_DMA
bool
default y
config GENERIC_ISA_DMA
bool
default y
config ARCH_NO_VIRT_TO_BUS
def_bool y
config OF
def_bool y
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>
2008-02-08 12:21:26 +00:00
config HZ
int
default 100
source "init/Kconfig"
menu "General machine setup"
config SMP
bool "Symmetric multi-processing support (does not work on sun4/sun4c)"
---help---
This enables support for systems with more than one CPU. If you have
a system with only one CPU, say N. If you have a system with more
than one CPU, say Y.
If you say N here, the kernel will run on single and multiprocessor
machines, but will use only one CPU of a multiprocessor machine. If
you say Y here, the kernel will run on many, but not all,
singleprocessor machines. On a singleprocessor machine, the kernel
will run faster if you say N here.
People using multiprocessor machines who say Y here should also say
Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
Management" code will be disabled if you say Y here.
See also <file:Documentation/nmi_watchdog.txt> and the SMP-HOWTO
available at <http://www.tldp.org/docs.html#howto>.
If you don't know what to do here, say N.
config NR_CPUS
int "Maximum number of CPUs (2-32)"
range 2 32
depends on SMP
default "32"
config SPARC
bool
default y
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_ARCH_KGDB if !SMP
select HAVE_ARCH_TRACEHOOK
# Identify this as a Sparc32 build
config SPARC32
bool
default y
help
SPARC is a family of RISC microprocessors designed and marketed by
Sun Microsystems, incorporated. They are very widely found in Sun
workstations and clones. This port covers the original 32-bit SPARC;
it is old and stable and usually considered one of the "big three"
along with the Intel and Alpha ports. The UltraLinux project
maintains both the SPARC32 and SPARC64 ports; its web page is
available at <http://www.ultralinux.org/>.
# Global things across all Sun machines.
config ISA
bool
help
ISA is found on Espresso only and is not supported currently.
Say N
config EISA
bool
help
EISA is not supported.
Say N
config MCA
bool
help
MCA is not supported.
Say N
config PCMCIA
tristate
---help---
Say Y here if you want to attach PCMCIA- or PC-cards to your Linux
computer. These are credit-card size devices such as network cards,
modems or hard drives often used with laptops computers. There are
actually two varieties of these cards: the older 16 bit PCMCIA cards
and the newer 32 bit CardBus cards. If you want to use CardBus
cards, you need to say Y here and also to "CardBus support" below.
To use your PC-cards, you will need supporting software from David
Hinds' pcmcia-cs package (see the file <file:Documentation/Changes>
for location). Please also read the PCMCIA-HOWTO, available from
<http://www.tldp.org/docs.html#howto>.
To compile this driver as modules, choose M here: the
modules will be called pcmcia_core and ds.
config SBUS
bool
default y
config SBUSCHAR
bool
default y
config SERIAL_CONSOLE
bool
default y
---help---
If you say Y here, it will be possible to use a serial port as the
system console (the system console is the device which receives all
kernel messages and warnings and which allows logins in single user
mode). This could be useful if some terminal or printer is connected
to that serial port.
Even if you say Y here, the currently visible virtual console
(/dev/tty0) will still be used as the system console by default, but
you can alter that using a kernel command line option such as
"console=ttyS1". (Try "man bootparam" or see the documentation of
your boot loader (silo) about how to pass options to the kernel at
boot time.)
If you don't have a graphics card installed and you say Y here, the
kernel will automatically use the first serial line, /dev/ttyS0, as
system console.
If unsure, say N.
config SUN_AUXIO
bool
default y
config SUN_IO
bool
default y
config RWSEM_GENERIC_SPINLOCK
bool
default y
config RWSEM_XCHGADD_ALGORITHM
bool
config GENERIC_FIND_NEXT_BIT
bool
default y
config GENERIC_HWEIGHT
bool
default y
config GENERIC_CALIBRATE_DELAY
bool
default y
config ARCH_MAY_HAVE_PC_FDC
bool
default y
config ARCH_HAS_ILOG2_U32
bool
default n
config ARCH_HAS_ILOG2_U64
bool
default n
config EMULATED_CMPXCHG
bool
default y
help
Sparc32 does not have a CAS instruction like sparc64. cmpxchg()
is emulated, and therefore it is not completely atomic.
config SUN_PM
bool
default y
help
Enable power management and CPU standby features on supported
SPARC platforms.
config SUN4
bool "Support for SUN4 machines (disables SUN4[CDM] support)"
depends on !SMP
default n
help
Say Y here if, and only if, your machine is a sun4. Note that
a kernel compiled with this option will run only on sun4.
(And the current version will probably work only on sun4/330.)
if !SUN4
config PCI
bool "Support for PCI and PS/2 keyboard/mouse"
help
CONFIG_PCI is needed for all JavaStation's (including MrCoffee),
CP-1200, JavaEngine-1, Corona, Red October, and Serengeti SGSC.
All of these platforms are extremely obscure, so say N if unsure.
config PCI_SYSCALL
def_bool PCI
source "drivers/pci/Kconfig"
endif
config NO_DMA
def_bool !PCI
config SUN_OPENPROMFS
tristate "Openprom tree appears in /proc/openprom"
help
If you say Y, the OpenPROM device tree will be available as a
virtual file system, which you can mount to /proc/openprom by "mount
-t openpromfs none /proc/openprom".
To compile the /proc/openprom support as a module, choose M here: the
module will be called openpromfs.
Only choose N if you know in advance that you will not need to modify
OpenPROM settings on the running system.
config SPARC_LED
tristate "Sun4m LED driver"
help
This driver toggles the front-panel LED on sun4m systems
in a user-specifiable manner. Its state can be probed
by reading /proc/led and its blinking mode can be changed
via writes to /proc/led
source "fs/Kconfig.binfmt"
source "mm/Kconfig"
endmenu
source "net/Kconfig"
source "drivers/Kconfig"
if !SUN4
source "drivers/sbus/char/Kconfig"
endif
# This one must be before the filesystem configs. -DaveM
menu "Unix98 PTY support"
config UNIX98_PTYS
bool "Unix98 PTY support"
---help---
A pseudo terminal (PTY) is a software device consisting of two
halves: a master and a slave. The slave device behaves identical to
a physical terminal; the master device is used by a process to
read data from and write data to the slave, thereby emulating a
terminal. Typical programs for the master side are telnet servers
and xterms.
Linux has traditionally used the BSD-like names /dev/ptyxx for
masters and /dev/ttyxx for slaves of pseudo terminals. This scheme
has a number of problems. The GNU C library glibc 2.1 and later,
however, supports the Unix98 naming standard: in order to acquire a
pseudo terminal, a process opens /dev/ptmx; the number of the pseudo
terminal is then made available to the process and the pseudo
terminal slave can be accessed as /dev/pts/<number>. What was
traditionally /dev/ttyp2 will then be /dev/pts/2, for example.
The entries in /dev/pts/ are created on the fly by a virtual
file system; therefore, if you say Y here you should say Y to
"/dev/pts file system for Unix98 PTYs" as well.
If you want to say Y here, you need to have the C library glibc 2.1
or later (equal to libc-6.1, check with "ls -l /lib/libc.so.*").
Read the instructions in <file:Documentation/Changes> pertaining to
pseudo terminals. It's safe to say N.
endmenu
source "fs/Kconfig"
source "arch/sparc/Kconfig.debug"
source "security/Kconfig"
source "crypto/Kconfig"
source "lib/Kconfig"