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f0d1b0b30d
This facility provides three entry points:
ilog2() Log base 2 of unsigned long
ilog2_u32() Log base 2 of u32
ilog2_u64() Log base 2 of u64
These facilities can either be used inside functions on dynamic data:
int do_something(long q)
{
...;
y = ilog2(x)
...;
}
Or can be used to statically initialise global variables with constant values:
unsigned n = ilog2(27);
When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant. They treat negative numbers as
unsigned.
When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.
[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
205 lines
3.3 KiB
Plaintext
205 lines
3.3 KiB
Plaintext
#
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# For a description of the syntax of this configuration file,
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# see Documentation/kbuild/kconfig-language.txt.
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#
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mainmenu "Linux Kernel Configuration"
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config AVR32
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bool
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default y
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# With EMBEDDED=n, we get lots of stuff automatically selected
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# that we usually don't need on AVR32.
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select EMBEDDED
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help
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AVR32 is a high-performance 32-bit RISC microprocessor core,
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designed for cost-sensitive embedded applications, with particular
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emphasis on low power consumption and high code density.
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There is an AVR32 Linux project with a web page at
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http://avr32linux.org/.
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config UID16
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bool
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config GENERIC_HARDIRQS
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bool
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default y
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config HARDIRQS_SW_RESEND
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bool
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default y
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config GENERIC_IRQ_PROBE
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bool
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default y
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config RWSEM_GENERIC_SPINLOCK
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bool
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default y
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config GENERIC_TIME
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bool
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default y
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config RWSEM_XCHGADD_ALGORITHM
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bool
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config ARCH_HAS_ILOG2_U32
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bool
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default n
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config ARCH_HAS_ILOG2_U64
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bool
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default n
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config GENERIC_BUST_SPINLOCK
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bool
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config GENERIC_HWEIGHT
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bool
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default y
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config GENERIC_CALIBRATE_DELAY
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bool
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default y
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source "init/Kconfig"
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menu "System Type and features"
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config SUBARCH_AVR32B
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bool
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config MMU
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bool
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config PERFORMANCE_COUNTERS
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bool
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config PLATFORM_AT32AP
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bool
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select SUBARCH_AVR32B
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select MMU
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select PERFORMANCE_COUNTERS
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choice
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prompt "AVR32 CPU type"
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default CPU_AT32AP7000
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config CPU_AT32AP7000
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bool "AT32AP7000"
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select PLATFORM_AT32AP
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endchoice
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#
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# CPU Daughterboards for ATSTK1000
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config BOARD_ATSTK1002
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bool
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choice
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prompt "AVR32 board type"
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default BOARD_ATSTK1000
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config BOARD_ATSTK1000
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bool "ATSTK1000 evaluation board"
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select BOARD_ATSTK1002 if CPU_AT32AP7000
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endchoice
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choice
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prompt "Boot loader type"
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default LOADER_U_BOOT
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config LOADER_U_BOOT
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bool "U-Boot (or similar) bootloader"
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endchoice
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config LOAD_ADDRESS
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hex
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default 0x10000000 if LOADER_U_BOOT=y && CPU_AT32AP7000=y
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config ENTRY_ADDRESS
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hex
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default 0x90000000 if LOADER_U_BOOT=y && CPU_AT32AP7000=y
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config PHYS_OFFSET
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hex
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default 0x10000000 if CPU_AT32AP7000=y
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source "kernel/Kconfig.preempt"
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config HAVE_ARCH_BOOTMEM_NODE
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bool
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default n
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config ARCH_HAVE_MEMORY_PRESENT
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bool
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default n
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config NEED_NODE_MEMMAP_SIZE
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bool
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default n
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config ARCH_FLATMEM_ENABLE
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bool
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default y
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config ARCH_DISCONTIGMEM_ENABLE
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bool
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default n
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config ARCH_SPARSEMEM_ENABLE
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bool
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default n
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source "mm/Kconfig"
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config OWNERSHIP_TRACE
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bool "Ownership trace support"
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default y
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help
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Say Y to generate an Ownership Trace message on every context switch,
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enabling Nexus-compliant debuggers to keep track of the PID of the
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currently executing task.
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# FPU emulation goes here
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source "kernel/Kconfig.hz"
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config CMDLINE
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string "Default kernel command line"
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default ""
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help
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If you don't have a boot loader capable of passing a command line string
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to the kernel, you may specify one here. As a minimum, you should specify
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the memory size and the root device (e.g., mem=8M, root=/dev/nfs).
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endmenu
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menu "Bus options"
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config PCI
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bool
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source "drivers/pci/Kconfig"
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source "drivers/pcmcia/Kconfig"
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endmenu
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menu "Executable file formats"
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source "fs/Kconfig.binfmt"
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endmenu
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source "net/Kconfig"
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source "drivers/Kconfig"
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source "fs/Kconfig"
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source "arch/avr32/Kconfig.debug"
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source "security/Kconfig"
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source "crypto/Kconfig"
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source "lib/Kconfig"
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