From: Dave Hansen <dave.hansen@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
peterz@infradead.org, luto@kernel.org, x86@kernel.org,
torvalds@linux-foundation.org, akpm@linux-foundation.org
Subject: [PATCH 2/5] x86/mpx: remove build infrastructure
Date: Thu, 23 Jan 2020 11:05:00 -0800 [thread overview]
Message-ID: <20200123190500.9119F8F4@viggo.jf.intel.com> (raw)
In-Reply-To: <20200123190456.8E05ADE6@viggo.jf.intel.com>
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
_
next prev parent reply other threads:[~2020-01-23 19:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-23 19:04 [PATCH 0/5] x86: finish the MPX removal process Dave Hansen
2020-01-23 19:04 ` [PATCH 1/5] x86/alternatives: add missing insn.h include Dave Hansen
2020-01-23 19:05 ` Dave Hansen [this message]
2020-01-23 19:05 ` [PATCH 3/5] x86/mpx: remove bounds exception code Dave Hansen
2020-01-23 19:05 ` [PATCH 4/5] mm: remove arch_bprm_mm_init() hook Dave Hansen
2020-01-23 19:05 ` [PATCH 5/5] x86/mpx: remove MPX from arch/x86 Dave Hansen
2020-01-23 19:26 ` [PATCH 0/5] x86: finish the MPX removal process Linus Torvalds
2020-01-23 20:26 ` Borislav Petkov
2020-01-23 21:23 ` Dave Hansen
2020-01-24 0:01 ` Linus Torvalds
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