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From: tip-bot for Dave Hansen <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: jannh@google.com, sean.j.christopherson@intel.com, hpa@zytor.com,
	luto@kernel.org, tglx@linutronix.de, dave.hansen@linux.intel.com,
	linux-kernel@vger.kernel.org, mingo@kernel.org,
	peterz@infradead.org
Subject: [tip:x86/mm] x86/mm: Add clarifying comments for user addr space
Date: Tue, 9 Oct 2018 08:03:44 -0700	[thread overview]
Message-ID: <tip-5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e@git.kernel.org> (raw)
In-Reply-To: <20180928160225.FFD44B8D@viggo.jf.intel.com>

Commit-ID:  5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e
Gitweb:     https://git.kernel.org/tip/5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e
Author:     Dave Hansen <dave.hansen@linux.intel.com>
AuthorDate: Fri, 28 Sep 2018 09:02:25 -0700
Committer:  Peter Zijlstra <peterz@infradead.org>
CommitDate: Tue, 9 Oct 2018 16:51:16 +0200

x86/mm: Add clarifying comments for user addr space

The SMAP and Reserved checking do not have nice comments.  Add
some to clarify and make it match everything else.

Cc: x86@kernel.org
Cc: Jann Horn <jannh@google.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180928160225.FFD44B8D@viggo.jf.intel.com
---
 arch/x86/mm/fault.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 0d1f5d39fc63..1d838701a5f7 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1276,9 +1276,17 @@ void do_user_addr_fault(struct pt_regs *regs,
 	if (unlikely(kprobes_fault(regs)))
 		return;
 
+	/*
+	 * Reserved bits are never expected to be set on
+	 * entries in the user portion of the page tables.
+	 */
 	if (unlikely(hw_error_code & X86_PF_RSVD))
 		pgtable_bad(regs, hw_error_code, address);
 
+	/*
+	 * Check for invalid kernel (supervisor) access to user
+	 * pages in the user address space.
+	 */
 	if (unlikely(smap_violation(hw_error_code, regs))) {
 		bad_area_nosemaphore(regs, hw_error_code, address, NULL);
 		return;

  reply	other threads:[~2018-10-09 15:04 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-28 16:02 [PATCH 0/8] [v2] x86/mm: page fault handling cleanups Dave Hansen
2018-09-28 16:02 ` [PATCH 1/8] x86/mm: clarify hardware vs. software "error_code" Dave Hansen
2018-10-09 15:02   ` [tip:x86/mm] x86/mm: Clarify " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 2/8] x86/mm: break out kernel address space handling Dave Hansen
2018-10-09 15:02   ` [tip:x86/mm] x86/mm: Break " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 3/8] x86/mm: break out user " Dave Hansen
2018-10-09 15:03   ` [tip:x86/mm] x86/mm: Break " tip-bot for Dave Hansen
2018-10-15  5:43     ` Eric W. Biederman
2018-10-19  5:58       ` Ingo Molnar
2018-09-28 16:02 ` [PATCH 4/8] x86/mm: add clarifying comments for user addr space Dave Hansen
2018-10-09 15:03   ` tip-bot for Dave Hansen [this message]
2018-09-28 16:02 ` [PATCH 5/8] x86/mm: fix exception table comments Dave Hansen
2018-10-09 15:04   ` [tip:x86/mm] x86/mm: Fix " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 6/8] x86/mm: add vsyscall address helper Dave Hansen
2018-10-09 15:04   ` [tip:x86/mm] x86/mm: Add " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 7/8] x86/mm/vsyscall: consider vsyscall page part of user address space Dave Hansen
2018-10-09 15:05   ` [tip:x86/mm] x86/mm/vsyscall: Consider " tip-bot for Dave Hansen
2018-09-28 16:02 ` [PATCH 8/8] x86/mm: remove spurious fault pkey check Dave Hansen
2018-10-09 15:05   ` [tip:x86/mm] x86/mm: Remove " tip-bot for Dave Hansen
2018-10-02  9:54 ` [PATCH 0/8] [v2] x86/mm: page fault handling cleanups Peter Zijlstra

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