It's a thin userland wrapper around adjtime(2). It can be used
to view current pending time adjustments, and root can use it to
smoothly adjust the system time.
As far as I can tell, other systems don't have a userland utility
for this, but it seems useful. Useful enough that I'm adding it to
the lagom build so I can use it on my linux box too :)
Now that we have a standalone test-js program, the "-t" test mode of the
js REPL is unused and can simply be removed. Required functionality has
been duplicated in test-js (isStrictMode function, loading of testing
utilities).
Also remove outdated information about tests from the js(1) man page.
All threads were running with iomapbase=0 in their TSS, which the CPU
interprets as "there's an I/O permission bitmap starting at offset 0
into my TSS".
Because of that, any bits that were 1 inside the TSS would allow the
thread to execute I/O instructions on the port with that bit index.
Fix this by always setting the iomapbase to sizeof(TSS32), and also
setting the TSS descriptor's limit to sizeof(TSS32), effectively making
the I/O permissions bitmap zero-length.
This should make it no longer possible to do I/O from userspace. :^)
This prevents code running outside of kernel mode from using the
following instructions:
* SGDT - Store Global Descriptor Table
* SIDT - Store Interrupt Descriptor Table
* SLDT - Store Local Descriptor Table
* SMSW - Store Machine Status Word
* STR - Store Task Register
There's no need for userspace to be able to use these instructions so
let's just disable them to prevent information leakage.
Add an option "-A", that will run all of the crash types in the crash
program. In this mode, all crash tests are run in a child process so
that the crash program does not crash.
Crash uses the return status of the child process to ascertain whether
the crash happened as expected.
This patch makes it possible to make memory regions non-readable.
This is enforced using the "present" bit in the page tables.
A process that hits an not-present page fault in a non-readable
region will be crashed.
