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From: Dave Hansen <dave@sr71.net>
To: linux-kernel@vger.kernel.org
Cc: x86@kernel.org, linux-api@vger.kernel.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	torvalds@linux-foundation.org, akpm@linux-foundation.org,
	Dave Hansen <dave@sr71.net>,
	dave.hansen@linux.intel.com
Subject: [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit
Date: Tue, 07 Jun 2016 13:47:14 -0700	[thread overview]
Message-ID: <20160607204714.DBBB24D2@viggo.jf.intel.com> (raw)
In-Reply-To: <20160607204712.594DE00A@viggo.jf.intel.com>


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
_

  reply	other threads:[~2016-06-07 20:47 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-06-07 20:47 [PATCH 0/9] [v2] System Calls for Memory Protection Keys Dave Hansen
2016-06-07 20:47 ` Dave Hansen [this message]
2016-06-07 20:47 ` [PATCH 2/9] mm: implement new pkey_mprotect() system call Dave Hansen
2016-06-07 20:47 ` [PATCH 3/9] x86, pkeys: make mprotect_key() mask off additional vm_flags Dave Hansen
2016-06-07 20:47 ` [PATCH 4/9] x86: wire up mprotect_key() system call Dave Hansen
2016-06-07 20:47 ` [PATCH 5/9] x86, pkeys: allocation/free syscalls Dave Hansen
2016-06-07 20:47 ` [PATCH 6/9] x86, pkeys: add pkey set/get syscalls Dave Hansen
2016-06-07 20:47 ` [PATCH 7/9] generic syscalls: wire up memory protection keys syscalls Dave Hansen
2016-06-07 21:25   ` Arnd Bergmann
2016-06-07 20:47 ` [PATCH 8/9] pkeys: add details of system call use to Documentation/ Dave Hansen
2016-06-07 20:47 ` [PATCH 9/9] x86, pkeys: add self-tests Dave Hansen
2016-06-08  9:23 ` [PATCH 0/9] [v2] System Calls for Memory Protection Keys Michael Kerrisk (man-pages)
2016-06-08 17:35   ` Dave Hansen
2016-06-09  0:01 [PATCH 0/9] [v3] " Dave Hansen
2016-06-09  0:01 ` [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen
2016-07-07 12:47 [PATCH 0/9] [REVIEW-REQUEST] [v4] System Calls for Memory Protection Keys Dave Hansen
2016-07-07 12:47 ` [PATCH 1/9] x86, pkeys: add fault handling for PF_PK page fault bit Dave Hansen
2016-07-07 14:40   ` Mel Gorman
2016-07-07 15:42     ` Dave Hansen

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