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[PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit

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From: Dave Hansen <dave.hansen@linux.intel.com>

PF_PK means that a memory access violated the protection key
access restrictions.  It is unconditionally an access_error()
because the permissions set on the VMA don't matter (the PKRU
value overrides it), and we never "resolve" PK faults (like
how a COW can "resolve write fault).

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
---

 b/arch/x86/mm/fault.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff -puN arch/x86/mm/fault.c~pkeys-105-add-pk-to-fault arch/x86/mm/fault.c
--- a/arch/x86/mm/fault.c~pkeys-105-add-pk-to-fault	2016-06-07 13:22:18.529937509 -0700
+++ b/arch/x86/mm/fault.c	2016-06-07 13:22:18.534937739 -0700
@@ -1112,6 +1112,15 @@ access_error(unsigned long error_code, s
 {
 	/* This is only called for the current mm, so: */
 	bool foreign = false;
+
+	/*
+	 * Read or write was blocked by protection keys.  This is
+	 * always an unconditional error and can never result in
+	 * a follow-up action to resolve the fault, like a COW.
+	 */
+	if (error_code & PF_PK)
+		return 1;
+
 	/*
 	 * Make sure to check the VMA so that we do not perform
 	 * faults just to hit a PF_PK as soon as we fill in a
_

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[PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
    Re: [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Arnd Bergmann <arnd@arndb.de> - 2016-06-07 23:30 +0200
  [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 4/9] x86: wire up mprotect_key() system call Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  [PATCH 5/9] x86, pkeys: allocation/free syscalls Dave Hansen <dave@sr71.net> - 2016-06-07 22:50 +0200
  Re: [PATCH 0/9] [v2] System Calls for Memory Protection Keys "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2016-06-08 11:30 +0200
    Re: [PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen <dave@sr71.net> - 2016-06-08 19:40 +0200

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