* [PATCH 1/3] kconfig: consolidate arch-specific seccomp options
2014-01-31 17:24 [PATCH 0/3] General Kconfig reorganization Dave Hansen
@ 2014-01-31 17:24 ` Dave Hansen
2014-01-31 17:24 ` [PATCH 2/3] Kconfig: collapse initrd in to own menu Dave Hansen
` (2 subsequent siblings)
3 siblings, 0 replies; 7+ messages in thread
From: Dave Hansen @ 2014-01-31 17:24 UTC (permalink / raw)
To: linux-kernel
Cc: torvalds, Dave Hansen, dave.hansen, mingo, benh,
linux-security-module, linux-arch, sfr, zohar, linux, monstr,
ralf, paulus, schwidefsky, heiko.carstens, lethal, x86,
james.l.morris
From: Dave Hansen <dave.hansen@linux.intel.com>
There are 7 architecures with "config SECCOMP". They all have
virtually the same help text except for those referencing the
/proc interface. The /proc interface was removed in 2007.
There is *NOTHING* architecture-specific about SECCOMP except
that the syscalls have per-architecture definitions, like every
other syscall. It is absurd to have the option in the
arch-specific menus.
Move it to the security menu, consolidate the 7 down to one, and
remove the embarassingly-ancient help text references and
dependencies on /proc.
Note that this changes the generic help text in the new,
consolidated config option. We want to emphasize that this
feature is about all untrusted machine code, not just bytecode.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linux-security-module@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: x86@kernel.org
Cc: James Morris <james.l.morris@oracle.com>
---
b/arch/arm/Kconfig | 15 +--------------
b/arch/microblaze/Kconfig | 18 +-----------------
b/arch/mips/Kconfig | 18 +-----------------
b/arch/powerpc/Kconfig | 18 +-----------------
b/arch/s390/Kconfig | 18 +-----------------
b/arch/sh/Kconfig | 17 +----------------
b/arch/sparc/Kconfig | 18 +-----------------
b/arch/x86/Kconfig | 17 +----------------
b/security/Kconfig | 20 +++++++++++++++++++-
9 files changed, 27 insertions(+), 132 deletions(-)
diff -puN arch/arm/Kconfig~consolidate-seccomp-options arch/arm/Kconfig
--- a/arch/arm/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.703436011 -0800
+++ b/arch/arm/Kconfig 2014-01-31 09:24:16.720436778 -0800
@@ -27,6 +27,7 @@ config ARM
select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
select HAVE_ARCH_KGDB
select HAVE_ARCH_SECCOMP_FILTER if (AEABI && !OABI_COMPAT)
+ select HAVE_ARCH_SECCOMP
select HAVE_ARCH_TRACEHOOK
select HAVE_BPF_JIT
select HAVE_CONTEXT_TRACKING
@@ -1874,20 +1875,6 @@ config UACCESS_WITH_MEMCPY
However, if the CPU data cache is using a write-allocate mode,
this option is unlikely to provide any performance gain.
-config SECCOMP
- bool
- prompt "Enable seccomp to safely compute untrusted bytecode"
- ---help---
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
config SWIOTLB
def_bool y
diff -puN arch/microblaze/Kconfig~consolidate-seccomp-options arch/microblaze/Kconfig
--- a/arch/microblaze/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.705436103 -0800
+++ b/arch/microblaze/Kconfig 2014-01-31 09:24:16.721436823 -0800
@@ -11,6 +11,7 @@ config MICROBLAZE
select ARCH_WANT_OPTIONAL_GPIOLIB
select HAVE_OPROFILE
select HAVE_ARCH_KGDB
+ select HAVE_ARCH_SECCOMP
select HAVE_DMA_ATTRS
select HAVE_DMA_API_DEBUG
select TRACING_SUPPORT
@@ -109,23 +110,6 @@ config CMDLINE_FORCE
Set this to have arguments from the default kernel command string
override those passed by the boot loader.
-config SECCOMP
- bool "Enable seccomp to safely compute untrusted bytecode"
- depends on PROC_FS
- default y
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via /proc/<pid>/seccomp, it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y. Only embedded should say N here.
-
endmenu
menu "Advanced setup"
diff -puN arch/mips/Kconfig~consolidate-seccomp-options arch/mips/Kconfig
--- a/arch/mips/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.707436192 -0800
+++ b/arch/mips/Kconfig 2014-01-31 09:24:16.722436868 -0800
@@ -11,6 +11,7 @@ config MIPS
select PERF_USE_VMALLOC
select HAVE_ARCH_KGDB
select HAVE_ARCH_TRACEHOOK
+ select HAVE_ARCH_SECCOMP
select ARCH_HAVE_CUSTOM_GPIO_H
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_TRACE_MCOUNT_TEST
@@ -2307,23 +2308,6 @@ config PHYSICAL_START
specified in the "crashkernel=YM@XM" command line boot parameter
passed to the panic-ed kernel).
-config SECCOMP
- bool "Enable seccomp to safely compute untrusted bytecode"
- depends on PROC_FS
- default y
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via /proc/<pid>/seccomp, it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y. Only embedded should say N here.
-
config USE_OF
bool
select OF
diff -puN arch/powerpc/Kconfig~consolidate-seccomp-options arch/powerpc/Kconfig
--- a/arch/powerpc/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.708436236 -0800
+++ b/arch/powerpc/Kconfig 2014-01-31 09:24:16.722436868 -0800
@@ -102,6 +102,7 @@ config PPC
select HAVE_EFFICIENT_UNALIGNED_ACCESS if !CPU_LITTLE_ENDIAN
select HAVE_KPROBES
select HAVE_ARCH_KGDB
+ select HAVE_ARCH_SECCOMP
select HAVE_KRETPROBES
select HAVE_ARCH_TRACEHOOK
select HAVE_MEMBLOCK
@@ -634,23 +635,6 @@ config ARCH_WANTS_FREEZER_CONTROL
source kernel/power/Kconfig
-config SECCOMP
- bool "Enable seccomp to safely compute untrusted bytecode"
- depends on PROC_FS
- default y
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via /proc/<pid>/seccomp, it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y. Only embedded should say N here.
-
endmenu
config ISA_DMA_API
diff -puN arch/s390/Kconfig~consolidate-seccomp-options arch/s390/Kconfig
--- a/arch/s390/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.710436327 -0800
+++ b/arch/s390/Kconfig 2014-01-31 09:24:16.723436913 -0800
@@ -105,6 +105,7 @@ config S390
select HAVE_ALIGNED_STRUCT_PAGE if SLUB
select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
select HAVE_ARCH_SECCOMP_FILTER
+ select HAVE_ARCH_SECCOMP
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_TRANSPARENT_HUGEPAGE if 64BIT
select HAVE_BPF_JIT if 64BIT && PACK_STACK
@@ -607,23 +608,6 @@ menu "Executable file formats / Emulatio
source "fs/Kconfig.binfmt"
-config SECCOMP
- def_bool y
- prompt "Enable seccomp to safely compute untrusted bytecode"
- depends on PROC_FS
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via /proc/<pid>/seccomp, it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y.
-
endmenu
menu "Power Management"
diff -puN arch/sh/Kconfig~consolidate-seccomp-options arch/sh/Kconfig
--- a/arch/sh/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.712436418 -0800
+++ b/arch/sh/Kconfig 2014-01-31 09:24:16.723436913 -0800
@@ -10,6 +10,7 @@ config SUPERH
select HAVE_OPROFILE
select HAVE_GENERIC_DMA_COHERENT
select HAVE_ARCH_TRACEHOOK
+ select HAVE_ARCH_SECCOMP
select HAVE_DMA_API_DEBUG
select HAVE_DMA_ATTRS
select HAVE_PERF_EVENTS
@@ -680,22 +681,6 @@ config PHYSICAL_START
where the fail safe kernel needs to run at a different address
than the panic-ed kernel.
-config SECCOMP
- bool "Enable seccomp to safely compute untrusted bytecode"
- depends on PROC_FS
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via prctl, it cannot be disabled and the task is only
- allowed to execute a few safe syscalls defined by each seccomp
- mode.
-
- If unsure, say N.
-
config SMP
bool "Symmetric multi-processing support"
depends on SYS_SUPPORTS_SMP
diff -puN arch/sparc/Kconfig~consolidate-seccomp-options arch/sparc/Kconfig
--- a/arch/sparc/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.713436462 -0800
+++ b/arch/sparc/Kconfig 2014-01-31 09:24:16.724436958 -0800
@@ -67,6 +67,7 @@ config SPARC64
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_CONTEXT_TRACKING
select HAVE_DEBUG_KMEMLEAK
+ select HAVE_ARCH_SECCOMP
select RTC_DRV_CMOS
select RTC_DRV_BQ4802
select RTC_DRV_SUN4V
@@ -223,23 +224,6 @@ config EARLYFB
help
Say Y here to enable a faster early framebuffer boot console.
-config SECCOMP
- bool "Enable seccomp to safely compute untrusted bytecode"
- depends on SPARC64 && PROC_FS
- default y
- help
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via /proc/<pid>/seccomp, it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y. Only embedded should say N here.
-
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs"
depends on SPARC64 && SMP
diff -puN arch/x86/Kconfig~consolidate-seccomp-options arch/x86/Kconfig
--- a/arch/x86/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.715436551 -0800
+++ b/arch/x86/Kconfig 2014-01-31 09:24:16.725437003 -0800
@@ -102,6 +102,7 @@ config X86
select GENERIC_SMP_IDLE_THREAD
select ARCH_WANT_IPC_PARSE_VERSION if X86_32
select HAVE_ARCH_SECCOMP_FILTER
+ select HAVE_ARCH_SECCOMP
select BUILDTIME_EXTABLE_SORT
select GENERIC_CMOS_UPDATE
select HAVE_ARCH_SOFT_DIRTY
@@ -1584,22 +1585,6 @@ config EFI_STUB
See Documentation/efi-stub.txt for more information.
-config SECCOMP
- def_bool y
- prompt "Enable seccomp to safely compute untrusted bytecode"
- ---help---
- This kernel feature is useful for number crunching applications
- that may need to compute untrusted bytecode during their
- execution. By using pipes or other transports made available to
- the process as file descriptors supporting the read/write
- syscalls, it's possible to isolate those applications in
- their own address space using seccomp. Once seccomp is
- enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
- and the task is only allowed to execute a few safe syscalls
- defined by each seccomp mode.
-
- If unsure, say Y. Only embedded should say N here.
-
source kernel/Kconfig.hz
config KEXEC
diff -puN security/Kconfig~consolidate-seccomp-options security/Kconfig
--- a/security/Kconfig~consolidate-seccomp-options 2014-01-31 09:24:16.717436643 -0800
+++ b/security/Kconfig 2014-01-31 09:24:16.725437003 -0800
@@ -167,5 +167,23 @@ config DEFAULT_SECURITY
default "yama" if DEFAULT_SECURITY_YAMA
default "" if DEFAULT_SECURITY_DAC
-endmenu
+config HAVE_ARCH_SECCOMP
+ bool
+
+config SECCOMP
+ def_bool y
+ depends on HAVE_ARCH_SECCOMP
+ prompt "Enable seccomp to safely compute untrusted bytecode"
+ ---help---
+ This kernel feature is useful to sandbox runtimes that need
+ to execute untrusted machine code. By using pipes or other
+ transports made available to the process as file descriptors
+ supporting the read/write syscalls, it's possible to isolate
+ those applications in their own address space using seccomp.
+ Once seccomp is enabled via prctl(PR_SET_SECCOMP), it cannot
+ be disabled and the task is only allowed to execute a few
+ safe syscalls defined by each seccomp mode.
+ If unsure, say Y. Only embedded should say N here.
+
+endmenu
_
^ permalink raw reply [flat|nested] 7+ messages in thread* [PATCH 3/3] Kconfig: organize memory-related config options
2014-01-31 17:24 [PATCH 0/3] General Kconfig reorganization Dave Hansen
2014-01-31 17:24 ` [PATCH 1/3] kconfig: consolidate arch-specific seccomp options Dave Hansen
2014-01-31 17:24 ` [PATCH 2/3] Kconfig: collapse initrd in to own menu Dave Hansen
@ 2014-01-31 17:24 ` Dave Hansen
2014-02-04 16:02 ` Dave Hansen
2014-02-01 19:12 ` [PATCH 0/3] General Kconfig reorganization Linus Torvalds
3 siblings, 1 reply; 7+ messages in thread
From: Dave Hansen @ 2014-01-31 17:24 UTC (permalink / raw)
To: linux-kernel; +Cc: torvalds, Dave Hansen, dave.hansen, linux-mm
From: Dave Hansen <dave.hansen@linux.intel.com>
This continues in a series of patches to clean up the
configuration menus. I believe they've become really hard to
navigate and there are some simple things we can do to make
things easier to find.
This creates a "Memory Options" menu and moves some things like
swap and slab configuration under them. It also moves SLUB_DEBUG
to the debugging menu.
After this patch, the menu has the following options:
[ ] Memory placement aware NUMA scheduler
[*] Enable VM event counters for /proc/vmstat
[ ] Disable heap randomization
[*] Support for paging of anonymous memory (swap)
Choose SLAB allocator (SLUB (Unqueued Allocator))
[*] SLUB per cpu partial cache
[*] SLUB: attempt to use double-cmpxchg operations
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: linux-mm@kvack.org
---
b/init/Kconfig | 243 +++++++++++++++++++++++++++--------------------------
b/mm/Kconfig.debug | 11 ++
2 files changed, 135 insertions(+), 119 deletions(-)
diff -puN init/Kconfig~organize-memory-config-options init/Kconfig
--- a/init/Kconfig~organize-memory-config-options 2014-01-31 09:24:17.328464183 -0800
+++ b/init/Kconfig 2014-01-31 09:24:17.334464455 -0800
@@ -208,16 +208,6 @@ config DEFAULT_HOSTNAME
but you may wish to use a different default here to make a minimal
system more usable with less configuration.
-config SWAP
- bool "Support for paging of anonymous memory (swap)"
- depends on MMU && BLOCK
- default y
- help
- This option allows you to choose whether you want to have support
- for so called swap devices or swap files in your kernel that are
- used to provide more virtual memory than the actual RAM present
- in your computer. If unsure say Y.
-
config SYSVIPC
bool "System V IPC"
---help---
@@ -760,6 +750,130 @@ endchoice
endmenu # "RCU Subsystem"
+menu "Memory Options"
+
+config NUMA_BALANCING
+ bool "Memory placement aware NUMA scheduler"
+ depends on ARCH_SUPPORTS_NUMA_BALANCING
+ depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
+ depends on SMP && NUMA && MIGRATION
+ help
+ This option adds support for automatic NUMA aware memory/task placement.
+ The mechanism is quite primitive and is based on migrating memory when
+ it has references to the node the task is running on.
+
+ This system will be inactive on UMA systems.
+
+config VM_EVENT_COUNTERS
+ default y
+ bool "Enable VM event counters for /proc/vmstat" if EXPERT
+ help
+ VM event counters are needed for event counts to be shown.
+ This option allows the disabling of the VM event counters
+ on EXPERT systems. /proc/vmstat will only show page counts
+ if VM event counters are disabled.
+
+config COMPAT_BRK
+ bool "Disable heap randomization"
+ default y
+ help
+ Randomizing heap placement makes heap exploits harder, but it
+ also breaks ancient binaries (including anything libc5 based).
+ This option changes the bootup default to heap randomization
+ disabled, and can be overridden at runtime by setting
+ /proc/sys/kernel/randomize_va_space to 2.
+
+ On non-ancient distros (post-2000 ones) N is usually a safe choice.
+
+config SWAP
+ bool "Support for paging of anonymous memory (swap)"
+ depends on MMU && BLOCK
+ default y
+ help
+ This option allows you to choose whether you want to have support
+ for so called swap devices or swap files in your kernel that are
+ used to provide more virtual memory than the actual RAM present
+ in your computer. If unsure say Y.
+
+choice
+ prompt "Choose SLAB allocator"
+ default SLUB
+ help
+ This option allows to select a slab allocator.
+
+config SLAB
+ bool "SLAB"
+ help
+ The regular slab allocator that is established and known to work
+ well in all environments. It organizes cache hot objects in
+ per cpu and per node queues.
+
+config SLUB
+ bool "SLUB (Unqueued Allocator)"
+ help
+ SLUB is a slab allocator that minimizes cache line usage
+ instead of managing queues of cached objects (SLAB approach).
+ Per cpu caching is realized using slabs of objects instead
+ of queues of objects. SLUB can use memory efficiently
+ and has enhanced diagnostics. SLUB is the default choice for
+ a slab allocator.
+
+config SLOB
+ depends on EXPERT
+ bool "SLOB (Simple Allocator)"
+ help
+ SLOB replaces the stock allocator with a drastically simpler
+ allocator. SLOB is generally more space efficient but
+ does not perform as well on large systems.
+
+endchoice
+
+config SLUB_CPU_PARTIAL
+ default y
+ depends on SLUB && SMP
+ bool "SLUB per cpu partial cache"
+ help
+ Per cpu partial caches accellerate objects allocation and freeing
+ that is local to a processor at the price of more indeterminism
+ in the latency of the free. On overflow these caches will be cleared
+ which requires the taking of locks that may cause latency spikes.
+ Typically one would choose no for a realtime system.
+
+config SLUB_ATTEMPT_CMPXCHG_DOUBLE
+ default y
+ depends on SLUB && HAVE_CMPXCHG_DOUBLE
+ bool "SLUB: attempt to use double-cmpxchg operations"
+ help
+ Some CPUs support instructions that let you do a large double-word
+ atomic cmpxchg operation. This keeps the SLUB fastpath from
+ needing to disable interrupts.
+
+ If you are unsure, say y.
+
+config MMAP_ALLOW_UNINITIALIZED
+ bool "Allow mmapped anonymous memory to be uninitialized"
+ depends on EXPERT && !MMU
+ default n
+ help
+ Normally, and according to the Linux spec, anonymous memory obtained
+ from mmap() has it's contents cleared before it is passed to
+ userspace. Enabling this config option allows you to request that
+ mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
+ providing a huge performance boost. If this option is not enabled,
+ then the flag will be ignored.
+
+ This is taken advantage of by uClibc's malloc(), and also by
+ ELF-FDPIC binfmt's brk and stack allocator.
+
+ Because of the obvious security issues, this option should only be
+ enabled on embedded devices where you control what is run in
+ userspace. Since that isn't generally a problem on no-MMU systems,
+ it is normally safe to say Y here.
+
+ See Documentation/nommu-mmap.txt for more information.
+
+endmenu # "Memory Optionse
+
config IKCONFIG
tristate "Kernel .config support"
---help---
@@ -840,18 +954,6 @@ config NUMA_BALANCING_DEFAULT_ENABLED
If set, automatic NUMA balancing will be enabled if running on a NUMA
machine.
-config NUMA_BALANCING
- bool "Memory placement aware NUMA scheduler"
- depends on ARCH_SUPPORTS_NUMA_BALANCING
- depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
- depends on SMP && NUMA && MIGRATION
- help
- This option adds support for automatic NUMA aware memory/task placement.
- The mechanism is quite primitive and is based on migrating memory when
- it has references to the node the task is running on.
-
- This system will be inactive on UMA systems.
-
menuconfig CGROUPS
boolean "Control Group support"
help
@@ -1517,103 +1619,6 @@ config DEBUG_PERF_USE_VMALLOC
endmenu
-config VM_EVENT_COUNTERS
- default y
- bool "Enable VM event counters for /proc/vmstat" if EXPERT
- help
- VM event counters are needed for event counts to be shown.
- This option allows the disabling of the VM event counters
- on EXPERT systems. /proc/vmstat will only show page counts
- if VM event counters are disabled.
-
-config SLUB_DEBUG
- default y
- bool "Enable SLUB debugging support" if EXPERT
- depends on SLUB && SYSFS
- help
- SLUB has extensive debug support features. Disabling these can
- result in significant savings in code size. This also disables
- SLUB sysfs support. /sys/slab will not exist and there will be
- no support for cache validation etc.
-
-config COMPAT_BRK
- bool "Disable heap randomization"
- default y
- help
- Randomizing heap placement makes heap exploits harder, but it
- also breaks ancient binaries (including anything libc5 based).
- This option changes the bootup default to heap randomization
- disabled, and can be overridden at runtime by setting
- /proc/sys/kernel/randomize_va_space to 2.
-
- On non-ancient distros (post-2000 ones) N is usually a safe choice.
-
-choice
- prompt "Choose SLAB allocator"
- default SLUB
- help
- This option allows to select a slab allocator.
-
-config SLAB
- bool "SLAB"
- help
- The regular slab allocator that is established and known to work
- well in all environments. It organizes cache hot objects in
- per cpu and per node queues.
-
-config SLUB
- bool "SLUB (Unqueued Allocator)"
- help
- SLUB is a slab allocator that minimizes cache line usage
- instead of managing queues of cached objects (SLAB approach).
- Per cpu caching is realized using slabs of objects instead
- of queues of objects. SLUB can use memory efficiently
- and has enhanced diagnostics. SLUB is the default choice for
- a slab allocator.
-
-config SLOB
- depends on EXPERT
- bool "SLOB (Simple Allocator)"
- help
- SLOB replaces the stock allocator with a drastically simpler
- allocator. SLOB is generally more space efficient but
- does not perform as well on large systems.
-
-endchoice
-
-config SLUB_CPU_PARTIAL
- default y
- depends on SLUB && SMP
- bool "SLUB per cpu partial cache"
- help
- Per cpu partial caches accellerate objects allocation and freeing
- that is local to a processor at the price of more indeterminism
- in the latency of the free. On overflow these caches will be cleared
- which requires the taking of locks that may cause latency spikes.
- Typically one would choose no for a realtime system.
-
-config MMAP_ALLOW_UNINITIALIZED
- bool "Allow mmapped anonymous memory to be uninitialized"
- depends on EXPERT && !MMU
- default n
- help
- Normally, and according to the Linux spec, anonymous memory obtained
- from mmap() has it's contents cleared before it is passed to
- userspace. Enabling this config option allows you to request that
- mmap() skip that if it is given an MAP_UNINITIALIZED flag, thus
- providing a huge performance boost. If this option is not enabled,
- then the flag will be ignored.
-
- This is taken advantage of by uClibc's malloc(), and also by
- ELF-FDPIC binfmt's brk and stack allocator.
-
- Because of the obvious security issues, this option should only be
- enabled on embedded devices where you control what is run in
- userspace. Since that isn't generally a problem on no-MMU systems,
- it is normally safe to say Y here.
-
- See Documentation/nommu-mmap.txt for more information.
-
config PROFILING
bool "Profiling support"
help
diff -puN mm/Kconfig.debug~organize-memory-config-options mm/Kconfig.debug
--- a/mm/Kconfig.debug~organize-memory-config-options 2014-01-31 09:24:17.330464274 -0800
+++ b/mm/Kconfig.debug 2014-01-31 09:24:17.334464455 -0800
@@ -27,3 +27,14 @@ config PAGE_POISONING
config PAGE_GUARD
bool
select WANT_PAGE_DEBUG_FLAGS
+
+config SLUB_DEBUG
+ default y
+ bool "Enable SLUB debugging support" if EXPERT
+ depends on SLUB && SYSFS
+ help
+ SLUB has extensive debug support features. Disabling these can
+ result in significant savings in code size. This also disables
+ SLUB sysfs support. /sys/slab will not exist and there will be
+ no support for cache validation etc.
+
_
^ permalink raw reply [flat|nested] 7+ messages in thread