Messages in this thread Patch in this message | | | Subject | [PATCH 2/5] x86/mpx: remove build infrastructure | From | Dave Hansen <> | Date | Thu, 23 Jan 2020 11:05:00 -0800 |
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From: Dave Hansen <dave.hansen@linux.intel.com>
MPX is being removed from the kernel due to a lack of support in the toolchain going forward (gcc).
Remove the Kconfig option and the Makefile line. This makes arch/x86/mm/mpx.c and anything under an #ifdef for X86_INTEL_MPX dead code.
Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> ---
b/arch/x86/Kconfig | 28 ---------------------------- b/arch/x86/mm/Makefile | 1 - 2 files changed, 29 deletions(-)
diff -puN arch/x86/Kconfig~mpx-remove-build arch/x86/Kconfig --- a/arch/x86/Kconfig~mpx-remove-build 2020-01-23 10:41:04.863942440 -0800 +++ b/arch/x86/Kconfig 2020-01-23 10:41:04.869942440 -0800 @@ -1896,34 +1896,6 @@ config X86_INTEL_UMIP specific cases in protected and virtual-8086 modes. Emulated results are dummy. -config X86_INTEL_MPX - prompt "Intel MPX (Memory Protection Extensions)" - def_bool n - # Note: only available in 64-bit mode due to VMA flags shortage - depends on CPU_SUP_INTEL && X86_64 - select ARCH_USES_HIGH_VMA_FLAGS - ---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.rst - - If unsure, say N. - config X86_INTEL_MEMORY_PROTECTION_KEYS prompt "Intel Memory Protection Keys" def_bool y diff -puN arch/x86/mm/Makefile~mpx-remove-build arch/x86/mm/Makefile --- a/arch/x86/mm/Makefile~mpx-remove-build 2020-01-23 10:41:04.865942440 -0800 +++ b/arch/x86/mm/Makefile 2020-01-23 10:41:04.870942440 -0800 @@ -45,7 +45,6 @@ obj-$(CONFIG_AMD_NUMA) += amdtopology.o obj-$(CONFIG_ACPI_NUMA) += srat.o obj-$(CONFIG_NUMA_EMU) += numa_emulation.o -obj-$(CONFIG_X86_INTEL_MPX) += mpx.o obj-$(CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS) += pkeys.o obj-$(CONFIG_RANDOMIZE_MEMORY) += kaslr.o obj-$(CONFIG_PAGE_TABLE_ISOLATION) += pti.o _
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