This new method is meant to be used in both userspace and kernel code.
The idea is to allow printing of a verbose message and then returning an
errno code which is the proper mechanism for kernel code because we
should almost always assume that such error will be propagated back to
userspace in some way, so the userspace code could reasonably decode it.
For userspace code however, this new method is meant to be a simple
wrapper for Error::from_string_view, because for most invocations, it's
much more useful to have a verbose & literal error than a errno code, so
we simply ignore that errno code completely in such context.
Returning literal strings is not the proper action here, because we
should always assume that error could be propagated back to userland, so
we need to keep a valid errno when returning an Error.
Returning literal strings is not the proper action here, because we
should always assume that error could be propagated back to userland, so
we need to keep a valid errno when returning an Error.
For example, consider cases where we want to propagate errors only in
specific instances:
auto result = read_data(); // something like ErrorOr<ByteBuffer>
if (result.is_error() && result.error().code() != EINTR)
continue;
auto bytes = TRY(result);
The TRY invocation will currently copy the byte buffer when the
expression (in this case, just a local variable) is stored into
_temporary_result.
This patch binds the expression to a reference to prevent such copies.
In less trival invocations (such as TRY(some_function()), this will
incur only temporary lifetime extensions, i.e. no functional change.
This is needed so we can retrieve the registers of a traced
thread that was attached to while it was running.
Attaching with ptrace to a running thread sends SIGSTOP to it.
This adds the necessary code to init.cpp to be able to execute the first
userspace process. To do this, first the filesystem code is initialized,
which will use the ramdisk embedded into the kernel image. Then the
first userspace process, /bin/SystemServer is executed. :^)
The ramdisk code is used as it is useful for the bring-up of the aarch64
port, however once the kernel has support for better ram-based
filesystems, the ramdisk code will be removed again.
The emulated aarch64 CPU does not contain the RNG cpu feature, so the
random number generator was not seeded. This commit adds a fallback to
use TimeManagement as a entropy source, such that get_good_random_bytes
works, which is needed for running the first userspace application on
aarch64.
This sets up the correct ThreadRegisters state when a process is
exec'ed, which happens when the first userspace application is executed.
Also changes Processor.cpp to get the stack pointer from the
ThreadRegisters.
This allows the function to be called from other translation units, in
particular this allows the CrashHandler.cpp file to be shared between
aarch64 and x86_64.
Setting the kernel_load_base variable caused backtracking to regress, so
to have proper backtracing the calculation of the symbol address in
KSyms.cpp needs to keep into account that the aarch64 kernel is linked
at a high virtual memory address.
When we execute in userspace, the exception level is EL0, so to handle
exceptions, such as interrupts, and syscalls, we need to add handlers to
vector_table.S. For now we only support running userspace applications
in AArch64 mode, so this commit only adds the handlers for that mode.
To detect instruction aborts, a helper to Registers.h is added, and used
in Interrupts.cpp. Additionally, the PageFault class gets a setter to
set the PageFaults m_is_instruction_fetch bool, and is also used in
Interrupts.cpp.
This reverts commit 4e0f85432a as the
ramdisk code is useful for the bring-up of the aarch64 port. Once the
kernel supports better ram-based filesystems, this code will be removed
again.
This replaces manually grabbing the thread's main lock.
This lets us remove the `get_thread_name` and `set_thread_name` syscalls
from the big lock. :^)
This filesystem is based on the code of the long-lived TmpFS. It differs
from that filesystem in one keypoint - its root inode doesn't have a
sticky bit on it.
Therefore, we mount it on /dev, to ensure only root can modify files on
that directory. In addition to that, /tmp is mounted directly in the
SystemServer main (start) code, so it's no longer specified in the fstab
file. We ensure that /tmp has a sticky bit and has the value 0777 for
root directory permissions, which is certainly a special case when using
RAM-backed (and in general other) filesystems.
Because of these 2 changes, it's no longer needed to maintain the TmpFS
filesystem, hence it's removed (renamed to RAMFS), because the RAMFS
represents the purpose of this filesystem in a much better way - it
relies on being backed by RAM "storage", and therefore it's easy to
conclude it's temporary and volatile, so its content is gone on either
system shutdown or unmounting of the filesystem.
When doing PT_SETREGS, we want to verify that the debugged thread is
executing in usermode.
b2f7ccf refactored things and flipped the relevant check around, which
broke things that use PT_SETREGS (for example, stepping over
breakpoints with sdb).
Splitting the I2C-related code lets the DisplayConnector code to utilize
I2C operations without caring about the specific details of the hardware
and allow future expansion of the driver to other newer generations
sharing the same GMBus code.
We should require a timeout for GMBus operations always, because faulty
hardware could let us just spin forever. Also, if nothing is listening
to the bus (which should result in a NAK), we could also spin forever.
Thanks to Andrew Kaster, which gave a review back in October, about a
big PR I opened (#15502), I managed to figure out why we always had a
problem with the first byte being read into the EDID buffer with the
GMBus code. It turns out that this simple invalid cast was making the
entire problem and using the correct AK::Array::data() method fixed this
notorious long standing problem for good.
This patch removes the x86 mechanism for calling syscalls, favoring
the more modern syscall instruction. It also moves architecture
dependent code from functions that are meant to be architecture
agnostic therefore paving the way for adding more architectures.
The function signal_trampoline_dummy was using int 0x82 to call
SC_sigreturn. Since x86 is no longer supported, the correct way
to call a syscall is using the syscall instruction.
This paves the way to remove the syscall trap handling mechanism.
