While this clutters Process.cpp a tiny bit, I feel that it's worth it:
- 2x speed on the kcov_loop benchmark. Likely more during fuzzing.
- Overall code complexity is going down with this change.
- By reducing the code reachable from __sanitizer_cov_trace_pc code,
we can now instrument more code.
Sticking this to the function source has multiple benefits:
- We instrument more code, by not excluding entire files.
- NO_SANITIZE_COVERAGE can be used in Header files.
- Keeping the info with the source code, means if a function or
file is moved around, the NO_SANITIZE_COVERAGE moves with it.
This reverts commit 9dbec601b0.
For KCOV to be performant (or at least not even slower) we need to
mmap the PC buffer from both user and kernel space at the same time.
You can't mmap a character device, so this change didn't make sense.
Plus even if we did invent a new method to exfiltrate the coverage
information out of the kernel, it would be incompatible with existing
kernel fuzzers. That would be kind of annoying. 🙃
This simple delay loop uses the time CSR to wait for the given amount
of time. The tick frequency of the CSR is read from the
/cpus/timebase-frequency devicetree property.
Instead, rewrite the region page fault handling code to not use
PageFault::type() on RISC-V.
I split Region::handle_fault into having a RISC-V-specific
implementation, as I am not sure if I cover all page fault handling edge
cases by solely relying on MM's own region metadata.
We should probably also take the processor-provided page fault reason
into account, if we decide to merge these two implementations in the
future.
This commit also removes the unnecessary user_sp RegisterState member.
We never use the kernel stack pointer on entry, so we can simply always
store the stack pointer of the previous privilege mode in sp.
Also remove the sp member from mcontext, as RISC-V doesn't have a
dedicated stack pointer register.
sp is defined to be x2 (x[1] in our case) by the ABI.
I probably accidentally included sp while copying the struct from
aarch64.
sepc has to be incremented before the call to syscall_handler,
as we otherwise would return to the ecall instruction, resulting in an
infinite trap loop.
We can't increment it after syscall_handler, as sepc might get changed
while handling the syscall.
The value of this field is incremented by one, as a value of 0 for this
field means 1 entry supported.
A value of 0xffff for CAP.MQES would incorrectly by truncated to 0x0000,
if we don't increase the bit width of the return type.
RFC9293 states that from the TimeWait state the TCPSocket
should wait the MSL (2mins) for delayed segments to expire
so that their sequence numbers do not clash with a new
connection's sequence numbers using the same ip address
and port number. The wait also ensures the remote TCP peer
has received the ACK to their FIN segment.
Please be aware that I only have NIC with chip version 6 so
this is the only one that I have tested. Rest was implemented
via looking at Linux rtl8169 driver. Also thanks to IdanHo
for some initial work.
Either we mount from a loop device or other source, the user might want
to obfuscate the given source for security reasons, so this option will
ensure this will happen.
If passed during a mount, the source will be hidden when reading from
the /sys/kernel/df node.
Similarly to DevPtsFS, this filesystem is about exposing loop device
nodes easily in /dev/loop, so userspace doesn't need to do anything in
order to use new devices immediately.
Instead of returning a raw pointer, which could be technically invalid
when using it in the caller function, we return a valid RefPtr of such
device.
This ensures that the code in DevPtsFS is now safe from a rare race
condition in which the SlavePTY device is gone but we still have a
pointer to it.
This device is a block device that allows a user to effectively treat an
Inode as a block device.
The static construction method is given an OpenFileDescription reference
but validates that:
- The description has a valid custody (so it's not some arbitrary file).
Failing this requirement will yield EINVAL.
- The description custody points to an Inode which is a regular file, as
we only support (seekable) regular files. Failing this requirement
will yield ENOTSUP.
LoopDevice can be used to mount a regular file on the filesystem like
other supported types of (physical) block devices.
Instead of using C-arrays, and manually counting their lengths, use
AK::Array. And pass these arrays around as spans, instead of as pointer-
and-length pairs.
Such operation is almost equivalent to writing on an Inode, so lock the
Inode m_inode_lock exclusively.
All FileSystem Inode implementations then override a new method called
truncate_locked which should implement the actual truncating.
thread_context_first_enter reuses the context restoring code in the
trap handler, just like other arches already do.
The `ld x2, 1*8(sp)` is unnecessary in the trap handler, as the stack
pointer should be equal to the stack pointer slot in the RegisterState
if the trap is from supervisor mode (and we currently don't support
user traps).
This load will however make us unable to reuse that code for
thread_context_first_enter.
This commit adds two functions which save/restore the entire FPU state.
On RISC-V, you only need to save the floating pointer registers
themselves and the fcsr CSR, which contains the entire state of the F/D
extensions.
Some real hardware apparently uses smaller BAR sizes than sizeof(HBA)
with a completely filled port_regs member.
Change the port_regs array to a flexible array member, so we don't panic
while verifying that the BAR size is large enough to map this struct.
Accesses to this array are already bounds checked against
AHCI::Limits::MaxPorts.
Allowing creation of StorageDevicePartition objects for any arbitrary
BlockDevice objects means that we could technically create a
StorageDevicePartition for another StorageDevicePartition which is
obviously not the intention for this code. Instead, require to pass a
StorageDevice reference to ensure this cannot happen.
It is expected that these class members will be set when the object is
created (so they're set in the class constructor method) and never
change again, as its the driver responsibility to find these values
before creating a StorageDevice object.
This makes it easier to rely on these values later on as we don't expect
them to ever change for a StorageDevice object during its lifetime.
It calculated the disk size with the zero-based max addressable block
value.
For example, for a disk device with a block size of 512 bytes that has 2
LBAs so it can address LBA 0 and LBA 1 (so m_max_addressable_block is 1)
the calculated disk size will be 512 instead of 1024 bytes.
We remove can_read() and can_write(), as both of these methods should be
implemented for proper blocking support.
For our case, the previous code will simply block the user if they tries
to read beyond the max addressable offset, which is not a correct
behavior.
Instead, just do proper EOF guarding when calling read() and write() on
such objects.
Add a method for matehmatical operations when verifying IO operation
boundaries.
Also, make max_addressable_block method non-virtual, since no other
derived class actually has ever overrided this method.
RFC9293 states that a closed socket should reply to all non-RST
packets with an RST. This change implements this behaviour as
specified in section 3.5.2 in bullet point 1.
The former automatically adapts the prefix to binary and octal
output, and is what we already use in the majority of cases.
Patch generated by:
rg -l '0x\{' | xargs sed -i '' -e 's/0x{:/{:#/'
I ran it 4 times (until it stopped changing things) since each
invocation only converted one instance per line.
No behavior change.
According to the Intel Software Developer's Manual Volume 3A section
6.12.1.3, the interrupt gate type means the IF flag is cleared to
prevent nested interruption. The trap gate type does not modify the
IF flag. Thus the gate type argument is important when constructing
an IDTEntry.
On x86_64 and x86, storage_segment (bit 12 counting from 0)
is always 0 according to the Intel Software Developer's Manual,
volume 3A, section 6.11 and section 6.14.1. It has therefore
been removed as a parameter from IDTEntry's constructor and
hardwired to 0.
In a TTY's non-canonical mode, data availability can be configured by
setting VMIN and VTIME to determine the minimum amount of bytes to read
and the timeout between bytes, respectively. Some ports (such as SRB2)
set VMIN to 0 which effectively makes reading a TTY such as stdin a
non-blocking read. We didn't support this, causing ports to hang as soon
as they try to read stdin without any data available.
Add a very duct-tapey implementation for the case where VMIN == 0 by
overwriting the TTY's description's blocking status; 3 FIXMEs are
included to make sure we clean this up some day.
This makes it possible to use MakeIndexSequqnce in functions like:
template<typename T, size_t N>
constexpr auto foo(T (&a)[N])
This means AK/StdLibExtraDetails.h must now include AK/Types.h
for size_t, which means AK/Types.h can no longer include
AK/StdLibExtras.h (which arguably it shouldn't do anyways),
which requires rejiggering some things.
(IMHO Types.h shouldn't use AK::Details metaprogramming at all.
FlatPtr doesn't necessarily have to use Conditional<> and ssize_t could
maybe be in its own header or something. But since it's tangential to
this PR, going with the tried and true "lift things that cause the
cycle up to the top" approach.)
This easily led to kernel deadlocks if the stopped thread held an
important global mutex (like the disk cache lock) while blocking.
Resolve this by ensuring stopped threads have a chance to return to the
userland boundary before actually stopping.
Locking a mutex while holding a spinlock is always wrong, but in the
case of the scheduler lock, it also causes an assertion failure. (Which
would be triggered by 2 separate threads trying to ptrace at the same
time).
This helps ensure no one accidentally accesses m_requests without first
locking it's spinlock. In fact this change fixed such a case, since
process_cq() implicitly assumed the caller locked the lock, which was
not the case for NVMePollQueue::submit_sqe().
Due to an incorrect lambda scope capture declaration, we would copy the
result status at the start of the function, before it actually got
updated with the final status. Capture it by reference instead to
ensure we report the updated result.
Instead of assuming data races won't occur and trying to somehow verify
it with manual un-atomic tracking, we can just use a recursive spinlock
instead of a normal one, to resolve the original deadlock.
Most of the actual logic is identical, with the only real difference
being that one wraps it with an async work item.
Merge the implementations to reduce duplications (which will also
require the fixes in the next commits to only be done once).
Multiple fields in sstatus are defined as WPRI "Reserved Writes Preserve
Values, Reads Ignore Values", which means we have to preserve their
values when writing to other fields in the same CSR.
We don't really need to touch any fields except SIE.
Interrupts are probably already disabled, but just to be safe,
disable them explicitly.
We need to handle the character map to set the code point before we can
reassign the correct key to the queued_event.key. This fixes keyboard
shortcuts using the incorrect keys based on the keyboard layout.
Automarks are similar to bookmarks placed by the terminal, allowing the
user to selectively remove a single command and its output from the
terminal scrollback.
This commit implements a single way to add marks: automatically placing
them when the shell becomes interactive.
To make sure the shell behaves correctly after its expected prompt
position changes, the terminal layer forces a resize event to be passed
to the shell on such (possibly) partial clears; this also has the nice
side effect of fixing the disappearing prompt on the preexisting "clear
including history" action: Fixes#4192.
I just copy-pasted microseconds_since_boot and
set_interrupt_interval_usec from aarch64.
However, on RISC-V, they are not in microseconds.
The TimerRegisters struct is also unused.
current_time and set_compare can also be private and static.
IRQHandler is not the correct class to inherit from, as the timer
is not connected to an IRQController.
Each hart has one of these Timers directly connected to it.
I originally added this header because I misunderstood how
IRQControllers are supposed to be used.
I thought that I would need a IRQController class for the hart-local
interrupt controller, but apparently, this class is supposed to be used
for non-local interrupt controllers like the IOAPIC or RISC-V PLIC.
x86 LAPICs don't use this class either.
I am not sure why 096cecb95e disabled the stack protector and sanitizers
for all files, but this is not necessary.
Only the pre_init code needs to run without them, as that code runs
identity mapped.
SysFS, ProcFS and DevPtsFS were all sending filetype 0 when traversing
their directories, but it is actually very easy to send proper filetypes
in these filesystems.
This patch binds all RAM backed filesystems to use only one enum for
their internal filetype, to simplify the implementation and allow
sharing of code.
Please note that the Plan9FS case is currently not solved as I am not
familiar with this filesystem and its constructs.
The ProcFS mostly keeps track of the filetype, and a fix was needed for
the /proc root directory - all processes exhibit a directory inside it
which makes it very easy to hardcode the directory filetype for them.
There's also the `self` symlink inode which is now exposed as DT_LNK.
As for SysFS, we could leverage the fact everything inherits from the
SysFSComponent class, so we could have a virtual const method to return
the proper filetype.
Most of the files in SysFS are "regular" files though, so the base class
has a non-pure virtual method.
Lastly, the DevPtsFS simply hardcodes '.' and '..' as directory file
type, and everything else is hardcoded to send the character device file
type, as this filesystem is only exposing character pts device files.
This is for some reason needed for riscv64 clang, as otherwise the
kernel.map file would grow too big to fit in its section inside the
kernel image.
None of our other architectures have temporary locals in their
kernel.map.
We initialize the MMU by first setting up the page tables for the
kernel image and the initial kernel stack.
Then we jump to a identity mapped page which makes the newly created
kernel root page table active by setting `satp` and then jumps to
`init`.
This trap handler uses the SBI to print an error message via a newly
introduced panic function, which is necessary as `pre_init` is running
identity mapped.
Also add a header file for `pre_init.cpp` as we wan't to use the panic
and `dbgln` function in the MMU init code as well.
We first try to use the newer "SRST" extension for rebooting and
shutting down and if that fails, we try to shutdown using the legacy
"System Shutdown" extension (which can't reboot, so we always shutdown).
The kernel will halt, if we return from here due to all attempts at
rebooting / shutting down failing.
This device will be used by userspace to read mouse packets from all
mouse devices that are attached to the machine.
This change is a preparation before we can enable seamless hotplug
capabilities in WindowServer for mouse devices, without any major change
on the userspace side.
We do this by implementing the following fixes:
- The Key_Plus is assigned to a proper map entry index now which is 0x4e
both on the keypad and non-keypad keys.
- Shift+Q now prints out "Q" properly on scan code set 2.
- Key BackSlash (or Pipe on shift key being pressed down) is now working
properly as well.
- Key_Pipe (which is "|" for en-US layout) is now working in scan code
set 2.
- Numpad keys as well as the decimal separator key are working again.
According to RFC 9293 Section 3.6.1. Half-Closed Connections, we should
still accept incoming packets in the FinWait2 state. Additionally, we
didn't handle the FIN+ACK case. We should handle this the same we
handle the FIN flag. The ACK is only added to signify successful
reception of the last packet.
The specification uses awkward numbering, marking the first byte as 7,
and the last one as 0, which caused me to misunderstand their ordering,
and use the last byte's address as the first one, and so on.
This scan code set is more advanced than the basic scan code set 1, and
is required to be supported for some bare metal hardware that might not
properly enable the PS2 first port translation in the i8042 controller.
LibWeb can now also generate bindings for keyboard events like the Pause
key, as well as other function keys (such as Right Alt, etc).
The logic for handling scan code sets is implemented by the PS2 keyboard
driver and is abstracted from the main HID KeyboardDevice code which
only handles "standard" KeyEvent(s).
RISC-V uses a different convention for storing stack frame information
described here: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/blob/master/riscv-cc.adoc#frame-pointer-convention
This part of the psABI is not yet in a ratified version, but both GCC
and Clang seem to use this convention.
Note that the backtrace dumping code still won't work for the initial
stack, as it is located before `kernel_mapping_base`.
To allow for easy mapping between the kernel virtual addresses and
KASAN shadow memory, we map shadow memory at the very end of the
virtual range, so that we can index into it using just an offset.
To ensure this range is free when needed, we restrict the possible
KASLR range when KASAN is enabled to make sure we don't use the end of
the virtual range.
This fixes the random kernel panics that could occur when KASAN is
enabled, if the kernel was randomly placed at the very end of the
virtual range.
This commit adds minimal support for compiler-instrumentation based
memory access sanitization.
Currently we only support detection of kmalloc redzone accesses, and
kmalloc use-after-free accesses.
Support for inline checks (for improved performance), and for stack
use-after-return and use-after-return detection is left for future PRs.
This scan code set is more advanced than the basic scan code set 1, and
is required to be supported for some bare metal hardware that might not
properly enable the PS2 first port translation in the i8042 controller.
LibWeb can now also generate bindings for keyboard events like the Pause
key, as well as other function keys (such as Right Alt, etc).
The logic for handling scan code sets is implemented by the PS2 keyboard
driver and is abstracted from the main HID KeyboardDevice code which
only handles "standard" KeyEvent(s).
