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Subject[PATCH 00/11] x86: Supervisor Mode Access Prevention
Date
Supervisor Mode Access Prevention (SMAP) is a new security feature
disclosed by Intel in revision 014 of the Intel® Architecture
Instruction Set Extensions Programming Reference:

http://software.intel.com/sites/default/files/319433-014.pdf

When SMAP is active, the kernel cannot normally access pages that are
user space (U=1). Since the kernel does have the need to access user
space pages under specific circumstances, an override is provided: the
kernel can access user space pages if EFLAGS.AC=1. For system data
structures, e.g. descriptor tables, that are accessed by the processor
directly, SMAP is active even in CPL 3 regardless of EFLAGS.AC.

SMAP also includes two new instructions, STAC and CLAC, to flip the AC
flag more quickly.

Note: patch 01/11 is already in tip:x86/cpufeature.

List of patches:
x86, cpufeature: Add feature bit for SMAP
x86-32, mm: The WP test should be done on a kernel page
x86, smap: Add CR4 bit for SMAP
x86, alternative: Use .pushsection/.popsection
x86, alternative: Add header guards to <asm/alternative-asm.h>
x86, smap: Add a header file with macros for STAC/CLAC
x86, uaccess: Merge prototypes for clear_user/__clear_user
x86, smap: Add STAC and CLAC instructions to control user space access
x86, smap: Turn on Supervisor Mode Access Prevention
x86, smap: A page fault due to SMAP is an oops
x86, smap: Reduce the SMAP overhead for signal handling

Diff stat:

Documentation/kernel-parameters.txt | 6 ++-
arch/x86/Kconfig | 11 ++++
arch/x86/ia32/ia32_signal.c | 12 +++--
arch/x86/ia32/ia32entry.S | 6 ++
arch/x86/include/asm/alternative-asm.h | 9 +++-
arch/x86/include/asm/alternative.h | 32 ++++++------
arch/x86/include/asm/cpufeature.h | 1 +
arch/x86/include/asm/fpu-internal.h | 10 ++--
arch/x86/include/asm/futex.h | 19 +++++--
arch/x86/include/asm/processor-flags.h | 1 +
arch/x86/include/asm/smap.h | 91 ++++++++++++++++++++++++++++++++
arch/x86/include/asm/uaccess.h | 28 ++++++----
arch/x86/include/asm/uaccess_32.h | 3 -
arch/x86/include/asm/uaccess_64.h | 3 -
arch/x86/include/asm/xsave.h | 10 ++--
arch/x86/kernel/cpu/common.c | 29 ++++++++++-
arch/x86/kernel/entry_64.S | 11 ++++-
arch/x86/kernel/signal.c | 24 +++++----
arch/x86/lib/copy_user_64.S | 7 +++
arch/x86/lib/copy_user_nocache_64.S | 3 +
arch/x86/lib/getuser.S | 10 ++++
arch/x86/lib/putuser.S | 8 +++-
arch/x86/lib/usercopy_32.c | 13 ++++-
arch/x86/lib/usercopy_64.c | 3 +
arch/x86/mm/fault.c | 18 ++++++
arch/x86/mm/init_32.c | 2 +-
26 files changed, 301 insertions(+), 69 deletions(-)
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