- Fix headings
- Consistent & more accurate code block language specifiers
- Add some newlines where appropriate
- Remove the strange "run ninja but actually you don't have to run ninja
as ninja install takes care of that" part
- Don't repeat specific build commands in "Ports" section
- Reword "Keymap" section to more generic "Customize disk image"
The system is extremely sensitive to heap allocations during heap
expansion. This was causing frequent OOM panics under various loads.
Work around the issue for now by putting the logging behind
KMALLOC_DEBUG. Ideally dmesgln() & friends would not reqiure any
heap allocations, but we're not there right now.
Fixes#5724.
Otherwise `reposition_cursor()` will move the cursor one character too
far to the right, and since we don't redraw the entire buffer when
the character is inserted at the end, the mistake won't be immediately
fixed by a complete redraw.
Fixes#5722
The previous architecture had a huge flaw: the pointer to the protected
data was itself unprotected, allowing you to overwrite it at any time.
This patch reorganizes the protected data so it's part of the Process
class itself. (Actually, it's a new ProcessBase helper class.)
We use the first 4 KB of Process objects themselves as the new storage
location for protected data. Then we make Process objects page-aligned
using MAKE_ALIGNED_ALLOCATED.
This allows us to easily turn on/off write-protection for everything in
the ProcessBase portion of Process. :^)
Thanks to @bugaevc for pointing out the flaw! This is still not perfect
but it's an improvement.
Old behavior: Crash due to VERIFY, unless we're completely and entirely out of
memory (m_available_ranges being empty), in which case it would return -ENOMEM.
New behavior: Return ENOMEM (and don't crash). In the case of nullptr,
also emit a helpful diagnostic.
Note that MAP_FIXED with nullptr is technically okay, but tends to be a sign
that something went wrong.
Also, this should improve mmap performance marginally, as it pulls the check out
of a loop that does not modify any parts of the check.
UE is now self-hosting! Fixes#5709.
However, this still needs some love: "ue UserspaceEmulator true" spits out tons
of error messages, probably false-positives, and takes about 229 seconds to run.
Then again, true-in-ue-in-ue-in-Qemu is three levels of emulation, so no wonder
it takes a long time! :D
Since there is usually no correlation between guest memory-layout and UE memory-layout,
this option does not make any sense. Especially since we provide nullptr.
This was misleading. The spec just wants us to check a string matches
a string in the JavaScript MIME type essence list. It doesn't want us
to parse the string as a MIME type to then use its essence for the
check.
Renames "mime_type" to "string" to make this less misleading.
Process member variable like m_euid are very valuable targets for
kernel exploits and until now they have been writable at all times.
This patch moves m_euid along with a whole bunch of other members
into a new Process::ProtectedData struct. This struct is remapped
as read-only memory whenever we don't need to write to it.
This means that a kernel write primitive is no longer enough to
overwrite a process's effective UID, you must first unprotect the
protected data where the UID is stored. :^)
This was using up to 12KB of kernel stack in the triply indirect case
and looks generally spooky. Let's just allocate a ByteBuffer for now
and take the performance hit (of heap allocation). Longer term we can
reorganize the code to reduce the majority of the heap churn.
