I discovered that QEMU has a "remote" option to the `-vnc` switch, which
causes it to reverse-connect to a VNC client on start. I've added this
into qemu.sh as the -r option.
Having main.cpp in the kernel and in the application being debugged is
annoying when setting breakpoints, so just like with main() vs
kernel_main(), kernel/main.cpp is now kernel/kernel_main.cpp.
The clang __builtin_* functions cannot be relied upon, as they may just
emit a call to the stdlib version. So this commit adds an implementation
for ceil and frexpr, as well as their float versions.
In preparation for futexes, I wanted to make kobjects a bit lighter.
Storing 32 bits of object id, and 8 bits of type (and not ending the
class in a ushort for handle count, which meant all kobjects were likely
to have a bunch of pad bytes), the kobject class data is now just one 8
byte word.
Also from this, change logs that mention threads or processes from
printing the full koid to just 2 bytes of object id from both process
and thread, which makes following the logs much easier.
This new class makes it easier for user programs to spawn threads. This
change also includes support for .hh files in modules, to differentiate
headers that are C++-only in system libraries.
The status code from thread exit had too many issues, (eg, how does it
relate to process exit code? what happens when different threads exit
with different exit codes?) and not enough value, so I'm getting rid of
it.
In the new mailbox structure, passing a j6_handle_invalid with a message
would result in a permission denied result, as the process did not have
a handle "0".
When the bootloader loads srv.init's program sections into memory, it
needed to page-align them if they weren't. srv.init's loader itself
handles this case, but the bootloader's did not.
heap_allocator::reallocate relies on the allocate and free methods so
mostly doesn't need locking, but it does touch the tracking map, so
needs to protect that with a lock.
A number of simplifications of mailboxes now that the interface is much
simpler, and synchronous.
* call and respond can now only transfer one handle at a time
* mailbox objects got rid of the message queue, and just have
wait_queues of blocked threads, and a reply_to map.
* threads now have a message_data struct on them for use by mailboxes
Instead of handles / capabilities having numeric ids that are only valid
for the owning process, they are now global in a system capabilities
table. This will allow for specifying capabilities in IPC that doesn't
need to be kernel-controlled.
Processes will still need to be granted access to given capabilities,
but that can become a simpler system call than the current method of
sending them through mailbox messages (and worse, having to translate
every one into a new capability like was the case before). In order to
track which handles a process has access to, a new node_set based on
node_map allows for an efficient storage and lookup of handles.
When node_map grew, it was not properly applying the fixup routine to
non-moved elements. This fixes the grow algorithm to:
1. Realloc the array and set all new slots to empty/invalid
2. Check each old slot and remove/reinsert the item if it exists and its
optimal slot is later in the array than its current slot
3. Reverse-iterate the original slots and call fixup() on empty slots to
keep items from being located after a more-optimal empty slot
Also fixed the fixup() function to not need to be called in a loop
anymore, as it's only used the one way - on a given empty slot, looping
until it hits an empty slot or optimally-placed item.
The allocator is a interface for types that expose allocator functions
for use in container templates like node_map (usage coming soon).
Also added an implementation for the kernel heap allocator.
The heap_allocator::get_free(order) function returns a reference to the
head pointer of the given freelist, so that it can be manipulated.
However, split_off was also taking a reference to a pointer for an out
param - passing the freelist pointer in here caused split_off to modify
the freelist.
I cleaned up a bunch of the places the freelist pointers were being
touched to make the usage more explicit.
Adding pretty printers to aid in debugging:
* For the cap_table type so that `p g_cap_table` displays a neat table
* For node_sets of handles to easily see what handles a process owns
* For util::vector to include its contents in the output
Created a new util/node_map.h that implements a map that grows in-place.
Now this is used for tracking blocks' size orders, instead of a header
at the start of the memory block. This allows the whole buddy block to
be allocated, allowing for page-aligned (or greater) blocks to be
requested from the heap.
The kernel log levels are now numerically reversed so that more-verbose
levels can be added to the end. Replaced 'debug' with 'verbose', and
added new 'spam' level.
lld started creating ELF files with OSABI set to GNU instead of SysV.
Make sure to pass the option to tell lld we want plain SysV binaries.
Also, some debug output in boot if verification fails in ELF loading.
In order to more easily express constants as bitsets, add more constexpr
to util::bitset. This allows expressing uint64_t constants as bitsets in
the code instead, without changing the generated assembly, to make code
more readable.
Rearranging of the ISR vectors for eventual TPR priority. Also removed
excess IRQs - if we need to support more than 64 IRQ vectors, we can add
some more back in.
Also clean up the legacy PIC init/masking code.
Previously, when adding a new thread, we only ever added it to the
current CPU and relied on work stealing to balance the CPUs. This commit
has the scheduler schedule new tasks round-robin across CPUs in hopes of
having to steal fewer tasks.
Also adds the run_queue.prev pointer for debugging what task was just
running on the given CPU.
The printf library I have been using, while useful, has way more than I
need in it, and had comparably huge stack space requirements. This
change adds a new util::format() which is a replacement for snprintf,
but with only the features used by kernel logging.
The logger has been changed to use it, as well as the few instances of
snprintf in the interrupt handling code before calling kassert.
Also part of this change: the logger's (now vestigial) immediate output
handling code is removed, as well as the "sequence" field on log
message headers.
The isr_prelude (and its IRQ equivalent) had been pushing RIP and RBP in
order to create a fake stack frame. This was in an effor to make GDB
display tracebacks more reliably, but GDB has other reasons for being
finnicky about stack frames, so this was just wasted. This commit gets
rid of it to make looking at the stack clearer.
In the beginning of the interrupt handler, we had previously checked if
the current handler had grabbed an IST stack from the IDT/TSS. If it
was, it saved this value and set it to 0 in the IDT, then restored it at
the end.
Now this is an atomic action. This is unlikely to make a difference
unless the interrupt handler is itself interrupted by an exception
before being able to swap the IDT value, but such a situation is now
impossible.
Previously, the CPU control registers were being set in a number of
different ways. Now, since the APs' need this to be set in the CPU
initialization code, always do it there. This removes some of the
settings from the bootloader, and some unused ones from smp.s.
Additionally, the control registers' flags are now enums in cpu.h and
manipulated via util::bitset.
The test_runner was potentially initializing the array of tests after
tests had been added. Now, allocate the vector dynamically on the first
test addition.
In bsp_early_init(), the BSP cpu_data's rsp0 was getting initialized to
the _value_ at the idle_stack_end symbol, instead of its address. I
don't believe this was causing any actual harm, but it was a red herring
when debugging.
The cpu::cpu_id class no longer looks up all known features in the
constructor, but instead provides access to the map of supported
features as a bitset from the verify() method. It also exposes the
brand_name() method instead of loading the brand name string in the
constructor and storing it as part of the object.
Add a new bitset class which allows for arbitrarily-large bit sets, with
specializations for 32 and 64 bit sets.
Eventually the enum_bitfields code should probably be reconsidered and
moved to bitsets, since it doesn't work everywhere.
This bug has been making me tear my hair out for weeks. When creating
the idle thread for each CPU, we were previously sharing stack areas
with other CPUs' idle threads in an effort to save memory. However, this
caused stack corruption that was very hard to track down. The kernel
stacks are in a vm_area_guarded to better detect this exact kind of
issue, but splitting stacks like this skirts that protection. It's not
worth saving a few KiB per CPU.
