Jessica Yu [off-list ref] writes:
quoted hunk ↗ jump to hunk
+++ Rusty Russell [29/06/16 10:38 +0930]:
quoted
Jessica Yu [off-list ref] writes:
quoted
Add ro_after_init support for modules by adding a new page-aligned section
in the module layout (after rodata) for ro_after_init data and enabling RO
protection for that section after module init runs.
Signed-off-by: Jessica Yu <redacted>
I would prefer a "bool after_init" flag to module_enable_ro(). It's
more explicit.
Sure thing, I was just initially worried about the
module_{enable,disable}_ro() asymmetry. :)
Yes, but I think compile-time-analyzable behaviour beats
runtime-analyzable behaviour for clarity.
quoted
Exposing the flags via uapi looks like a wart, but it's kind of a
feature, since we don't *unset* it in any section; userspace may want to
know about it.
Hm, I'm still unsure about this. I'm starting to think it might be a
bit overkill to expose SHF_RO_AFTER_INIT through uapi (although that
is where all the other SHF_* flags are defined) SHF_RO_AFTER_INIT
would technically be used only internally in the kernel (i.e. module
loader), and it'd also be considered a non-standard flag, using a bit
from SHF_MASKOS (OS-specific range). What do you think?
Some arch *could* use it by setting the flag in a section in their
module I think; we don't stop them. Since the other flags are there,
I'd leave it.
We don't expose the flags via sysfs, though, so that's the only
exposure.
Thanks!
Rusty.