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| author |   Dave Hansen <dave.hansen@linux.intel.com> | 2014-12-12 10:38:36 -0800 |
|---|---|---|
| committer |   Thomas Gleixner <tglx@linutronix.de> | 2014-12-15 15:58:57 +0100 |
| commit | 72e9b5fe9bee0826e7ce7599adbdc64e544780ef (patch) | |
| tree | ce252b251b1ca1732b9eaba4f5361d9d793b7828 | |
| parent | x86, mpx: Update documentation (diff) | |
| download | linux-dev-72e9b5fe9bee0826e7ce7599adbdc64e544780ef.tar.xz linux-dev-72e9b5fe9bee0826e7ce7599adbdc64e544780ef.zip | |
x86, mpx: Give MPX a real config option prompt
Give MPX a real config option. The CPUs that support it (referenced
here):
https://software.intel.com/en-us/forums/topic/402393
are not available publicly yet. Right now only the software emulator
provides MPX for the general public.
[ tglx: Make it default off. There is no point in having it on right
now as no hardware and no proper tooling support are available ]
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Dave Hansen <dave@sr71.net>
Link: http://lkml.kernel.org/r/20141212183836.2569D58D@viggo.jf.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| -rw-r--r-- | Documentation/x86/intel_mpx.txt | 6 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 30 |
2 files changed, 31 insertions, 5 deletions
diff --git a/Documentation/x86/intel_mpx.txt b/Documentation/x86/intel_mpx.txt index 6ca6e2bd9ae9..818518a3ff01 100644 --- a/Documentation/x86/intel_mpx.txt +++ b/Documentation/x86/intel_mpx.txt @@ -7,11 +7,15 @@ that can be used in conjunction with compiler changes to check memory references, for those references whose compile-time normal intentions are usurped at runtime due to buffer overflow or underflow. +You can tell if your CPU supports MPX by looking in /proc/cpuinfo: + + cat /proc/cpuinfo | grep ' mpx ' + For more information, please refer to Intel(R) Architecture Instruction Set Extensions Programming Reference, Chapter 9: Intel(R) Memory Protection Extensions. -Note: Currently no hardware with MPX ISA is available but it is always +Note: As of December 2014, no hardware with MPX is available but it is possible to use SDE (Intel(R) Software Development Emulator) instead, which can be downloaded from http://software.intel.com/en-us/articles/intel-software-development-emulator diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 967dfe0ba85e..cc91e5e55d13 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -248,10 +248,6 @@ config HAVE_INTEL_TXT def_bool y depends on INTEL_IOMMU && ACPI -config X86_INTEL_MPX - def_bool y - depends on CPU_SUP_INTEL - config X86_32_SMP def_bool y depends on X86_32 && SMP @@ -1575,6 +1571,32 @@ config X86_SMAP If unsure, say Y. +config X86_INTEL_MPX + prompt "Intel MPX (Memory Protection Extensions)" + def_bool n + depends on CPU_SUP_INTEL + ---help--- + MPX provides hardware features that can be used in + conjunction with compiler-instrumented code to check + memory references. It is designed to detect buffer + overflow or underflow bugs. + + This option enables running applications which are + instrumented or otherwise use MPX. It does not use MPX + itself inside the kernel or to protect the kernel + against bad memory references. + + Enabling this option will make the kernel larger: + ~8k of kernel text and 36 bytes of data on a 64-bit + defconfig. It adds a long to the 'mm_struct' which + will increase the kernel memory overhead of each + process and adds some branches to paths used during + exec() and munmap(). + + For details, see Documentation/x86/intel_mpx.txt + + If unsure, say N. + config EFI bool "EFI runtime service support" depends on ACPI |