From: Florian Weimer <fweimer@redhat.com>
To: DJ Delorie <dj@redhat.com>
Cc: "Richard Earnshaw \(lists\)" <Richard.Earnshaw@arm.com>,
libc-alpha@sourceware.org
Subject: Re: RFD - Support for memory tagging in GLIBC
Date: Tue, 10 Sep 2019 17:57:38 +0200 [thread overview]
Message-ID: <87tv9kxhxp.fsf@oldenburg2.str.redhat.com> (raw)
In-Reply-To: <xnftl5i8tc.fsf@greed.delorie.com> (DJ Delorie's message of "Mon, 09 Sep 2019 15:11:27 -0400")
* DJ Delorie:
> I wonder if we could generically abuse these bits on other architectures
> as well, but as a no-op? It might require some platform-independent
> kernel interface to say "I want my address space to ignore the top four
> bits please".
You can get hardware support for this using alias mappings, but it's
going to be some bits in the middle, not the top bits, and you'll
probably waste TLB slots. OpenJDK's ZGC does this even on aarch64
because as mentioned on this thread, the system calls currently expect
the canonical bits.
Thanks,
Florian
prev parent reply other threads:[~2019-09-10 15:57 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-06 9:14 RFD - Support for memory tagging in GLIBC Richard Earnshaw (lists)
2019-09-06 15:03 ` Paul Eggert
2019-09-10 14:38 ` Szabolcs Nagy
2019-09-10 14:55 ` Paul Eggert
2019-09-10 15:54 ` DJ Delorie
2019-09-09 19:11 ` DJ Delorie
2019-09-10 14:59 ` Szabolcs Nagy
2019-09-10 15:57 ` Florian Weimer [this message]
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