arch/sparc/Kconfig v5.13-rc1

64BIT

64-bit kernel" if "$(ARCH)" = "sparc

SPARC is a family of RISC microprocessors designed and marketed by
Sun Microsystems, incorporated.  They are very widely found in Sun
workstations and clones.

Say yes to build a 64-bit kernel - formerly known as sparc64
Say no to build a 32-bit kernel - formerly known as sparc


Menu: Processor type and features

SMP

Symmetric multi-processing support

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 uni- 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,
uniprocessor machines. On a uniprocessor 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/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO
available at <https://www.tldp.org/docs.html#howto>.

If you don't know what to do here, say N.

kernel/Kconfig.hz

EMULATED_CMPXCHG

Sparc32 does not have a CAS instruction like sparc64. cmpxchg()
is emulated, and therefore it is not completely atomic.

EARLYFB

Support for early boot text console

Say Y here to enable a faster early framebuffer boot console.

HOTPLUG_CPU

Support for hot-pluggable CPUs

Say Y here to experiment with turning CPUs off and on.  CPUs
can be controlled through /sys/devices/system/cpu/cpu#.
Say N if you want to disable CPU hotplug.

drivers/cpufreq/Kconfig

US3_MC

UltraSPARC-III Memory Controller driver

This adds a driver for the UltraSPARC-III memory controller.
Loading this driver allows exact mnemonic strings to be
printed in the event of a memory error, so that the faulty DIMM
on the motherboard can be matched to the error.

If in doubt, say Y, as this information can be very useful.

NODES_SHIFT

Maximum NUMA Nodes (as a power of 2)

Specify the maximum number of NUMA Nodes available on the target
system.  Increases memory reserved to accommodate various tables.

FORCE_MAX_ZONEORDER

Maximum zone order

The kernel memory allocator divides physically contiguous memory
blocks into "zones", where each zone is a power of two number of
pages.  This option selects the largest power of two that the kernel
keeps in the memory allocator.  If you need to allocate very large
blocks of physically contiguous memory, then you may need to
increase this value.

This config option is actually maximum order plus one. For example,
a value of 13 means that the largest free memory block is 2^12 pages.

kernel/power/Kconfig

SCHED_SMT

SMT (Hyperthreading) scheduler support

SMT scheduler support improves the CPU scheduler's decision making
when dealing with SPARC cpus at a cost of slightly increased overhead
in some places. If unsure say N here.

SCHED_MC

Multi-core scheduler support

Multi-core scheduler support improves the CPU scheduler's decision
making when dealing with multi-core CPU chips at a cost of slightly
increased overhead in some places. If unsure say N here.

CMDLINE

Initial kernel command string

Say Y here if you want to be able to pass default arguments to
the kernel. This will be overridden by the bootloader, if you
use one (such as SILO). This is most useful if you want to boot
a kernel from TFTP, and want default options to be available
with having them passed on the command line.

NOTE: This option WILL override the PROM bootargs setting!

SUN_PM

Enable power management and CPU standby features on supported
SPARC platforms.

SPARC_LED

Sun4m LED driver

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

SERIAL_CONSOLE

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.

SPARC_LEON

Sparc Leon processor family

If you say Y here if you are running on a SPARC-LEON processor.
The LEON processor is a synthesizable VHDL model of the
SPARC-v8 standard. LEON is  part of the GRLIB collection of
IP cores that are distributed under GPL. GRLIB can be downloaded
from www.gaisler.com. You can download a sparc-linux cross-compilation
toolchain at www.gaisler.com.


Menu: U-Boot options

UBOOT_LOAD_ADDR

uImage Load Address

U-Boot kernel load address, the address in physical address space
where u-boot will place the Linux kernel before booting it.
This address is normally the base address of main memory + 0x4000.

UBOOT_FLASH_ADDR

uImage.o Load Address

Optional setting only affecting the uImage.o ELF-image used to
download the uImage file to the target using a ELF-loader other than
U-Boot. It may for example be used to download an uImage to FLASH with
the GRMON utility before even starting u-boot.

UBOOT_ENTRY_ADDR

uImage Entry Address

Do not change this unless you know what you're doing. This is
hardcoded by the SPARC32 and LEON port.

This is the virtual address u-boot jumps to when booting the Linux
Kernel.




Menu: Bus options (PCI etc.)

SUN_LDOMS

Sun Logical Domains support

Say Y here is you want to support virtual devices via
Logical Domains.

SPARC_GRPCI1

GRPCI Host Bridge Support

Say Y here to include the GRPCI Host Bridge Driver. The GRPCI
PCI host controller is typically found in GRLIB SPARC32/LEON
systems. The driver has one property (all_pci_errors) controlled
from the bootloader that makes the GRPCI to generate interrupts
on detected PCI Parity and System errors.

SPARC_GRPCI2

GRPCI2 Host Bridge Support

Say Y here to include the GRPCI2 Host Bridge Driver.

SUN_OPENPROMFS

Openprom tree appears in /proc/openprom

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.


drivers/sbus/char/Kconfig