We can now test a _very_ basic transaction via `do_debug_transfer()`.
This function merely attaches some TDs to the LSCTRL queue head
and points some input and output buffers. We then sense an interrupt
with USBSTS value of 1, meaning Interrupt On Completion
(of the transaction). At this point, the input buffer is filled with
some data.
According the USB spec/UHCI datasheet (as well as the Linux and
BSD source code), if we receive an IRQ and USBSTS is 0, then
the IRQ does not belong to us and we should immediately jump
out of the handler.
We can now read/write to the two root ports exposed to the
UHCI controller, and detect when a device is plugged in or
out via a kernel process that constantly scans the port
for any changes. This is very basic, but is a bit of fun to see
the kernel detecting hardware on the fly :^)
Implemented both Queue Heads and Transfer Descriptors. These
are required to actually perform USB transactions. The UHCI
driver sets up a pool of these that can be allocated when we
need them. It seems some drivers have these statically
allocated, so it might be worth looking into that, but
for now, the simple way seems to be to allocate them on
the fly as we need them, and then release them.
It seems that not setting the framelist address register
was causing the entire system to lock up as it generated an insane
interrupt storm in the IRQ handler for the UHCI controller.
We now allocate a 4KiB aligned page via
`MemoryManager::allocate_supervisor_physical_page()` and set every
value to 1. In effect, this creates a framelist with each entry
being a "TERMINATE" entry in which the controller stalls until its'
1mS time slice is up.
Some more registers have also been set for consistency, though it
seems like this don't need to be set explicitly in software.
This patch adds sys$abort() which immediately crashes the process with
SIGABRT. This makes assertion backtraces a lot nicer by removing all
the gunk that otherwise happens between __assertion_failed() and
actually crashing from the SIGABRT.
When ProcFS could no longer allocate KBuffer objects to serve calls to
read, it would just return 0, indicating EOF. This then triggered
parsing errors because code assumed it read the file.
Because read isn't supposed to return ENOMEM, change ProcFS to populate
the file data upon file open or seek to the beginning. This also means
that calls to open can now return ENOMEM if needed. This allows the
caller to either be able to successfully open the file and read it, or
fail to open it in the first place.
Commit a3a9016701 removed the PT_INTERP header
from Loader.so which cleaned up some kernel code in execve. Unfortunately
it prevents Loader.so from being run as an executable
There is a window between dropping the last reference and removing
a ProcFSInode from the lookup map. So, when looking up we need to
check if that Inode is being destructed.
If a TLB flush request is broadcast to other processors and the addresses
to flush are user mode addresses, we can ignore such a request on the
target processor if the page directory currently in use doesn't match
the addresses to be flushed. We still need to broadcast to all processors
in that case because the other processors may switch to that same page
directory at any time.
If we remap pages (e.g. lazy allocation) inside a VMObject that is
shared among more than one region, broadcast it to any other region
that may be mapping the same page.
Lazily committed shared memory was not working in situations where one
process would write to the memory and another would only read from it.
Since the reading process would never cause a write fault in the shared
region, we'd never notice that the writing process had added real
physical pages to the VMObject. This happened because the lazily
committed pages were marked "present" in the page table.
This patch solves the issue by always allocating shared memory up front
and not trying to be clever about it.
Before this change, we would sometimes map a region into the address
space with !is_shared(), and then moments later call set_shared(true).
I found this very confusing while debugging, so this patch makes us pass
the initial shared flag to the Region constructor, ensuring that it's in
the correct state by the time we first map the region.
Insert stack canaries to find stack corruptions in the kernel.
It looks like this was enabled in the past (842716a) but appears to have been
lost during the CMake conversion.
The `-fstack-protector-strong` variant was chosen because it catches more issues
than `-fstack-protector`, but doesn't have substantial performance impact like
`-fstack-protector-all`.
This fixes a kernel crash that occured when calling ptrace with PT_PEEK
on non paged-in memory.
The crash occurred because we were holding the scheduler lock while
trying to read from the disk's block device, which we do not allow.
Fixes#4740
We need to allocate all pages for the profiler right away so that
we don't trigger page faults in the timer interrupt handler to
allocate them.
Fixes#4734
We need to free the regions before reverting the paging scope to the
original one when rolling back changes due to an error. This fixes
silent memory corruption.
By designating a committed page pool we can guarantee to have physical
pages available for lazy allocation in mappings. However, when forking
we will overcommit. The assumption is that worst-case it's better for
the fork to die due to insufficient physical memory on COW access than
the parent that created the region. If a fork wants to ensure that all
memory is available (trigger a commit) then it can use madvise.
This also means that fork now can gracefully fail if we don't have
enough physical pages available.
This brings mmap more in line with other operating systems. Prior to
this, it was impossible to request memory that was definitely committed,
instead MAP_PURGEABLE would provide a region that was not actually
purgeable, but also not fully committed, which meant that using such memory
still could cause crashes when the underlying pages could no longer be
allocated.
This fixes some random crashes in low-memory situations where non-volatile
memory is mapped (e.g. malloc, tls, Gfx::Bitmap, etc) but when a page in
these regions is first accessed, there is insufficient physical memory
available to commit a new page.
Rather than lazily committing regions by default, we now commit
the entire region unless MAP_NORESERVE is specified.
This solves random crashes in low-memory situations where e.g. the
malloc heap allocated memory, but using pages that haven't been
used before triggers a crash when no more physical memory is available.
Use this flag to create large regions without actually committing
the backing memory. madvise() can be used to commit arbitrary areas
of such regions after creating them.
This adds the ability for a Region to define volatile/nonvolatile
areas within mapped memory using madvise(). This also means that
memory purging takes into account all views of the PurgeableVMObject
and only purges memory that is not needed by all of them. When calling
madvise() to change an area to nonvolatile memory, return whether
memory from that area was purged. At that time also try to remap
all memory that is requested to be nonvolatile, and if insufficient
pages are available notify the caller of that fact.
Instead of specifying the boot argument to be root=/dev/hdXY, now
one can write root=PARTUUID= with the right UUID, and if the partition
is found, the kernel will boot from it.
This feature is mainly used with GUID partitions, and is considered to
be the most reliable way for the kernel to identify partitions.
RTTI is still disabled for the Kernel, and for the Dynamic Loader. This
allows for much less awkward navigation of class heirarchies in LibCore,
LibGUI, LibWeb, and LibJS (eventually). Measured RootFS size increase
was < 1%, and libgui.so binary size was ~3.3%. The small binary size
increase here seems worth it :^)
Use the GNU LD option --no-dynamic-linker. This allows uncommenting some
code in the Kernel that gets upset if your ELF interpreter has its own
interpreter.
Compared to version 10 this fixes a bunch of formatting issues, mostly
around structs/classes with attributes like [[gnu::packed]], and
incorrect insertion of spaces in parameter types ("T &"/"T &&").
I also removed a bunch of // clang-format off/on and FIXME comments that
are no longer relevant - on the other hand it tried to destroy a couple of
neatly formatted comments, so I had to add some as well.
BlockCondition::unblock should return true if it unblocked at
least one thread, not if iterating the blockers had been stopped.
This is a regression introduced by 49a76164c.
Fixes#4670
This assertion cannot be safely/reliably made in the
~SharedInodeVMObject destructor. The problem is that
Inode::is_shared_vmobject holds a weak reference to the instance
that is being destroyed (ref count 0). Checking the pointer using
WeakPtr::unsafe_ptr will produce nullptr depending on timing in
this case, and WeakPtr::safe_ref will reliably produce a nullptr
as soon as the reference count drops to 0. The only case where
this assertion could succeed is when WeakPtr::unsafe_ptr returned
the pointer because it won the race against revoking it. And
because WeakPtr::safe_ref will always return a nullptr, we cannot
reliably assert this from the ~SharedInodeVMObject destructor.
Fixes#4621
