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[Bug target/81490] x86: Handling of symbol ranges for __seg_fs/__seg_gs
- From: "hpa at zytor dot com" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 04 Aug 2017 00:07:03 +0000
- Subject: [Bug target/81490] x86: Handling of symbol ranges for __seg_fs/__seg_gs
- Auto-submitted: auto-generated
- References: <bug-81490-4@http.gcc.gnu.org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81490
--- Comment #19 from H. Peter Anvin <hpa at zytor dot com> ---
So the Linux kernel, right now, basically does (b); we'd like to do something
more like (a).
Because the stack canary (which is a percpu variable in the Linux kernel) is
hard-coded in gcc to be %gs:0x28, models (c) and (d) are not available to us.
Even if they were, it would have issues with moving modules further than 2G
from the main kernel.
We don't need the special relocations since we can see which references point
into the appropriate section during our post-link processing, but someone else
may have use for them.