mirror of
https://github.com/torvalds/linux.git
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7e0fb73c52
Pull string hash improvements from George Spelvin:
"This series does several related things:
- Makes the dcache hash (fs/namei.c) useful for general kernel use.
(Thanks to Bruce for noticing the zero-length corner case)
- Converts the string hashes in <linux/sunrpc/svcauth.h> to use the
above.
- Avoids 64-bit multiplies in hash_64() on 32-bit platforms. Two
32-bit multiplies will do well enough.
- Rids the world of the bad hash multipliers in hash_32.
This finishes the job started in commit 689de1d6ca ("Minimal
fix-up of bad hashing behavior of hash_64()")
The vast majority of Linux architectures have hardware support for
32x32-bit multiply and so derive no benefit from "simplified"
multipliers.
The few processors that do not (68000, h8/300 and some models of
Microblaze) have arch-specific implementations added. Those
patches are last in the series.
- Overhauls the dcache hash mixing.
The patch in commit 0fed3ac866 ("namei: Improve hash mixing if
CONFIG_DCACHE_WORD_ACCESS") was an off-the-cuff suggestion.
Replaced with a much more careful design that's simultaneously
faster and better. (My own invention, as there was noting suitable
in the literature I could find. Comments welcome!)
- Modify the hash_name() loop to skip the initial HASH_MIX(). This
would let us salt the hash if we ever wanted to.
- Sort out partial_name_hash().
The hash function is declared as using a long state, even though
it's truncated to 32 bits at the end and the extra internal state
contributes nothing to the result. And some callers do odd things:
- fs/hfs/string.c only allocates 32 bits of state
- fs/hfsplus/unicode.c uses it to hash 16-bit unicode symbols not bytes
- Modify bytemask_from_count to handle inputs of 1..sizeof(long)
rather than 0..sizeof(long)-1. This would simplify users other
than full_name_hash"
Special thanks to Bruce Fields for testing and finding bugs in v1. (I
learned some humbling lessons about "obviously correct" code.)
On the arch-specific front, the m68k assembly has been tested in a
standalone test harness, I've been in contact with the Microblaze
maintainers who mostly don't care, as the hardware multiplier is never
omitted in real-world applications, and I haven't heard anything from
the H8/300 world"
* 'hash' of git://ftp.sciencehorizons.net/linux:
h8300: Add <asm/hash.h>
microblaze: Add <asm/hash.h>
m68k: Add <asm/hash.h>
<linux/hash.h>: Add support for architecture-specific functions
fs/namei.c: Improve dcache hash function
Eliminate bad hash multipliers from hash_32() and hash_64()
Change hash_64() return value to 32 bits
<linux/sunrpc/svcauth.h>: Define hash_str() in terms of hashlen_string()
fs/namei.c: Add hashlen_string() function
Pull out string hash to <linux/stringhash.h>
299 lines
7.4 KiB
Plaintext
299 lines
7.4 KiB
Plaintext
config MICROBLAZE
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def_bool y
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select ARCH_HAS_GCOV_PROFILE_ALL
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select ARCH_MIGHT_HAVE_PC_PARPORT
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select ARCH_WANT_IPC_PARSE_VERSION
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select ARCH_WANT_OPTIONAL_GPIOLIB
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select BUILDTIME_EXTABLE_SORT
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select CLKSRC_OF
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select CLONE_BACKWARDS3
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select COMMON_CLK
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select GENERIC_ATOMIC64
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select GENERIC_CLOCKEVENTS
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select GENERIC_CPU_DEVICES
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select GENERIC_IDLE_POLL_SETUP
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select GENERIC_IRQ_PROBE
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select GENERIC_IRQ_SHOW
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select GENERIC_PCI_IOMAP
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select GENERIC_SCHED_CLOCK
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select HAVE_ARCH_HASH
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select HAVE_ARCH_KGDB
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select HAVE_DEBUG_KMEMLEAK
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select HAVE_DMA_API_DEBUG
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select HAVE_DYNAMIC_FTRACE
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select HAVE_FTRACE_MCOUNT_RECORD
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select HAVE_FUNCTION_GRAPH_TRACER
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select HAVE_FUNCTION_TRACER
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select HAVE_MEMBLOCK
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select HAVE_MEMBLOCK_NODE_MAP
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select HAVE_OPROFILE
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select IRQ_DOMAIN
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select MODULES_USE_ELF_RELA
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select OF
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select OF_EARLY_FLATTREE
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select TRACING_SUPPORT
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select VIRT_TO_BUS
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select CPU_NO_EFFICIENT_FFS
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config SWAP
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def_bool n
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config RWSEM_GENERIC_SPINLOCK
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def_bool y
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config ZONE_DMA
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def_bool 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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def_bool n
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config ARCH_HAS_ILOG2_U64
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def_bool n
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config GENERIC_HWEIGHT
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def_bool y
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config GENERIC_CALIBRATE_DELAY
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def_bool y
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config GENERIC_CSUM
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def_bool y
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config STACKTRACE_SUPPORT
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def_bool y
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config LOCKDEP_SUPPORT
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def_bool y
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source "init/Kconfig"
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source "kernel/Kconfig.freezer"
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source "arch/microblaze/Kconfig.platform"
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menu "Processor type and features"
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source "kernel/Kconfig.preempt"
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source "kernel/Kconfig.hz"
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config MMU
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bool "MMU support"
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default n
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comment "Boot options"
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config CMDLINE_BOOL
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bool "Default bootloader kernel arguments"
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config CMDLINE
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string "Default kernel command string"
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depends on CMDLINE_BOOL
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default "console=ttyUL0,115200"
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help
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On some architectures there is currently no way for the boot loader
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to pass arguments to the kernel. For these architectures, you should
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supply some command-line options at build time by entering them
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here.
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config CMDLINE_FORCE
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bool "Force default kernel command string"
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depends on CMDLINE_BOOL
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default n
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help
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Set this to have arguments from the default kernel command string
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override those passed by the boot loader.
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config SECCOMP
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bool "Enable seccomp to safely compute untrusted bytecode"
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depends on PROC_FS
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default y
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help
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This kernel feature is useful for number crunching applications
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that may need to compute untrusted bytecode during their
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execution. By using pipes or other transports made available to
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the process as file descriptors supporting the read/write
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syscalls, it's possible to isolate those applications in
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their own address space using seccomp. Once seccomp is
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enabled via /proc/<pid>/seccomp, it cannot be disabled
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and the task is only allowed to execute a few safe syscalls
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defined by each seccomp mode.
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If unsure, say Y. Only embedded should say N here.
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endmenu
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menu "Kernel features"
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config NR_CPUS
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int
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default "1"
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config ADVANCED_OPTIONS
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bool "Prompt for advanced kernel configuration options"
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help
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This option will enable prompting for a variety of advanced kernel
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configuration options. These options can cause the kernel to not
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work if they are set incorrectly, but can be used to optimize certain
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aspects of kernel memory management.
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Unless you know what you are doing, say N here.
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comment "Default settings for advanced configuration options are used"
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depends on !ADVANCED_OPTIONS
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config XILINX_UNCACHED_SHADOW
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bool "Are you using uncached shadow for RAM ?"
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depends on ADVANCED_OPTIONS && !MMU
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default n
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help
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This is needed to be able to allocate uncachable memory regions.
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The feature requires the design to define the RAM memory controller
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window to be twice as large as the actual physical memory.
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config HIGHMEM
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bool "High memory support"
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depends on MMU
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help
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The address space of Microblaze processors is only 4 Gigabytes large
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and it has to accommodate user address space, kernel address
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space as well as some memory mapped IO. That means that, if you
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have a large amount of physical memory and/or IO, not all of the
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memory can be "permanently mapped" by the kernel. The physical
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memory that is not permanently mapped is called "high memory".
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If unsure, say n.
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config LOWMEM_SIZE_BOOL
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bool "Set maximum low memory"
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depends on ADVANCED_OPTIONS && MMU
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help
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This option allows you to set the maximum amount of memory which
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will be used as "low memory", that is, memory which the kernel can
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access directly, without having to set up a kernel virtual mapping.
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This can be useful in optimizing the layout of kernel virtual
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memory.
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Say N here unless you know what you are doing.
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config LOWMEM_SIZE
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hex "Maximum low memory size (in bytes)" if LOWMEM_SIZE_BOOL
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default "0x30000000"
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config MANUAL_RESET_VECTOR
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hex "Microblaze reset vector address setup"
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default "0x0"
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help
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Set this option to have the kernel override the CPU Reset vector.
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If zero, no change will be made to the MicroBlaze reset vector at
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address 0x0.
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If non-zero, a jump instruction to this address, will be written
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to the reset vector at address 0x0.
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If you are unsure, set it to default value 0x0.
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config KERNEL_START_BOOL
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bool "Set custom kernel base address"
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depends on ADVANCED_OPTIONS
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help
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This option allows you to set the kernel virtual address at which
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the kernel will map low memory (the kernel image will be linked at
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this address). This can be useful in optimizing the virtual memory
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layout of the system.
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Say N here unless you know what you are doing.
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config KERNEL_START
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hex "Virtual address of kernel base" if KERNEL_START_BOOL
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default "0xc0000000" if MMU
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default KERNEL_BASE_ADDR if !MMU
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config TASK_SIZE_BOOL
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bool "Set custom user task size"
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depends on ADVANCED_OPTIONS && MMU
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help
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This option allows you to set the amount of virtual address space
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allocated to user tasks. This can be useful in optimizing the
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virtual memory layout of the system.
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Say N here unless you know what you are doing.
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config TASK_SIZE
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hex "Size of user task space" if TASK_SIZE_BOOL
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default "0x80000000"
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choice
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prompt "Page size"
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default MICROBLAZE_4K_PAGES
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depends on ADVANCED_OPTIONS && !MMU
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help
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Select the kernel logical page size. Increasing the page size
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will reduce software overhead at each page boundary, allow
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hardware prefetch mechanisms to be more effective, and allow
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larger dma transfers increasing IO efficiency and reducing
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overhead. However the utilization of memory will increase.
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For example, each cached file will using a multiple of the
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page size to hold its contents and the difference between the
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end of file and the end of page is wasted.
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If unsure, choose 4K_PAGES.
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config MICROBLAZE_4K_PAGES
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bool "4k page size"
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config MICROBLAZE_16K_PAGES
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bool "16k page size"
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config MICROBLAZE_64K_PAGES
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bool "64k page size"
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endchoice
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source "mm/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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menu "Bus Options"
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config PCI
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bool "PCI support"
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config PCI_DOMAINS
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def_bool PCI
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config PCI_DOMAINS_GENERIC
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def_bool PCI_DOMAINS
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config PCI_SYSCALL
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def_bool PCI
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config PCI_XILINX
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bool "Xilinx PCI host bridge support"
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depends on PCI
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source "drivers/pci/Kconfig"
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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/microblaze/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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