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[PATCH 08/32] x86, pkeys: new page fault error code bit: PF_PK

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

Note: "PK" is how the Intel SDM refers to this bit, so we also
use that nomenclature.

This only defines the bit, it does not plumb it anywhere to be
handled.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---

 b/arch/x86/mm/fault.c |    8 ++++++++
 1 file changed, 8 insertions(+)

diff -puN arch/x86/mm/fault.c~pkeys-05-pfec arch/x86/mm/fault.c
--- a/arch/x86/mm/fault.c~pkeys-05-pfec	2015-12-14 10:42:42.240777820 -0800
+++ b/arch/x86/mm/fault.c	2015-12-14 10:42:42.244778000 -0800
@@ -33,6 +33,7 @@
  *   bit 2 ==	 0: kernel-mode access	1: user-mode access
  *   bit 3 ==				1: use of reserved bit detected
  *   bit 4 ==				1: fault was an instruction fetch
+ *   bit 5 ==				1: protection keys block access
  */
 enum x86_pf_error_code {
 
@@ -41,6 +42,7 @@ enum x86_pf_error_code {
 	PF_USER		=		1 << 2,
 	PF_RSVD		=		1 << 3,
 	PF_INSTR	=		1 << 4,
+	PF_PK		=		1 << 5,
 };
 
 /*
@@ -916,6 +918,12 @@ static int spurious_fault_check(unsigned
 
 	if ((error_code & PF_INSTR) && !pte_exec(*pte))
 		return 0;
+	/*
+	 * Note: We do not do lazy flushing on protection key
+	 * changes, so no spurious fault will ever set PF_PK.
+	 */
+	if ((error_code & PF_PK))
+		return 1;
 
 	return 1;
 }
_
--
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[PATCH 00/32] x86: Memory Protection Keys (v7) Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 06/32] x86, pkeys: add PKRU xsave fields and data structure(s) Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 17/32] x86, pkeys: check VMAs and PTEs for protection keys Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 14/32] x86, pkeys: add functions to fetch PKRU Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
    Re: [PATCH 14/32] x86, pkeys: add functions to fetch PKRU Thomas Gleixner <tglx@linutronix.de> - 2015-12-14 21:00 +0100
  [PATCH 19/32] x86, pkeys: optimize fault handling in access_error() Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 10/32] x86, pkeys: arch-specific protection bits Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 13/32] x86, pkeys: fill in pkey field in siginfo Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 20/32] x86, pkeys: differentiate instruction fetches Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 05/32] x86, pkeys: define new CR4 bit Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 01/32] mm, gup: introduce concept of "foreign" get_user_pages() Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 08/32] x86, pkeys: new page fault error code bit: PF_PK Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 11/32] x86, pkeys: pass VMA down in to fault signal generation code Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  [PATCH 23/32] x86, pkeys: add Kconfig prompt to existing config option Dave Hansen <dave@sr71.net> - 2015-12-14 20:20 +0100
  Re: [PATCH 00/32] x86: Memory Protection Keys (v7) "Michael Kerrisk (man-pages)" <mtk.manpages@gmail.com> - 2015-12-24 12:40 +0100

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