Commit-ID: 5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e
Gitweb: https://git.kernel.org/tip/5b0c2cac54d44ea40d5c5aec7cbf14353b2a903e
Author: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
AuthorDate: Fri, 28 Sep 2018 09:02:25 -0700
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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@xxxxxxxxxx
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20180928160225.FFD44B8D@xxxxxxxxxxxxxxxxxx
---
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;
|