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[Bug target/82150] Produces a branch prefetch which causes a hang
- From: "mgretton at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Tue, 19 Sep 2017 15:01:38 +0000
- Subject: [Bug target/82150] Produces a branch prefetch which causes a hang
- Auto-submitted: auto-generated
- References: <bug-82150-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82150
mgretton at gcc dot gnu.org changed:
What |Removed |Added
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CC| |mgretton at gcc dot gnu.org
--- Comment #4 from mgretton at gcc dot gnu.org ---
As you suggest in your original comment this hang could be coming from the
instruction pre-fetch going to some place in memory that is mapped (and
executable) but the memory system is not giving a response to memory accesses
to that location.
As a general point all read sensitive devices must be marked as XN to prevent
speculative corruption of those read sensitive devices by instruction fetch
(this is true on future versions of the architecture as well).
Can you ensure that the XN-bit is set on memory pages mapped to read-sensitive
devices?
(XN description ARM11 MP Core TRM:
http://infocenter.arm.com/help/topic/com.arm.doc.ddi0360f/CACHFICI.html)