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 kernel/main.cpp and kernel/memory_bootstrap.cpp files had become
something of a junk drawer. This change cleans them up in the following
ways:
- Most CPU initialization has moved to cpu.cpp, allowing several
functions to be made static and removed from cpu.h
- Multi-core startup code has moved to the new smp.h and smp.cpp, and
ap_startup.s has been renamed smp.s to match.
- run_constructors() has moved to memory_bootstrap.cpp, and all the
functionality of that file has been hidden behind a new public
interface mem::initialize().
- load_init_server() has moved from memory_bootstrap.cpp to main.cpp
This commit contains a couple large, interdependent changes:
- In preparation for capability checking, the _syscall_verify_*
functions now load most handles passed in, and verify that they exist
and are of the correct type. Lists and out-handles are not converted
to objects.
- Also in preparation for capability checking, the internal
representation of handles has changed. j6_handle_t is now 32 bits, and
a new j6_cap_t (also 32 bits) is added. Handles of a process are now a
util::map<j6_handle_t, handle> where handle is a new struct containing
the id, capabilities, and object pointer.
- The kernel object definition DSL gained a few changes to support auto
generating the handle -> object conversion in the _syscall_verify_*
functions, mostly knowing the object type, and an optional "cname"
attribute on objects where their names differ from C++ code.
(Specifically vma/vm_area)
- Kernel object code and other code under kernel/objects is now in a new
obj:: namespace, because fuck you <cstdlib> for putting "system" in
the global namespace. Why even have that header then?
- Kernel object types constructed with the construct_handle helper now
have a creation_caps static member to declare what capabilities a
newly created object's handle should have.
In places where the "user" state is available, like interrupt handlers,
panic() and kassert() can now take an optional pointer to that user
cpu_state structure, and the panic handler will print that out as well.
Kernel panics previously only stopped the calling core. This commit
re-implements the panic system to allow us to stop all cores on a panic.
Changes include:
- panic now sends an NMI to all cores. This means we can't control the
contents of their registers, so panic information has been moved to a
global struct, and the panicking cpu sets the pointer to that data in
its cpu_data.
- the panic_handler is now set up with mutexes to print appropriately
and only initialize objects once.
- copying _current_gsbase into the panic handler, and #including the
cpprt.cpp file (so that we can define NDEBUG and not have it try to
link the assert code back in)
- making the symbol data pointer in kargs an actual pointer again, not
an address - and carrying that through to the panic handler
- the number of cpus is now saved globally in the kernel as g_num_cpus
I'm a tabs guy. I like tabs, it's an elegant way to represent
indentation instead of brute-forcing it. But I have to admit that the
world seems to be going towards spaces, and tooling tends not to play
nice with tabs. So here we go, changing the whole repo to spaces since
I'm getting tired of all the inconsistent formatting.
Created the framework for using different loadable panic handlers,
loaded by the bootloader. Initial panic handler is panic.serial, which
contains its own serial driver and stacktrace code.
Other related changes:
- Asserts are now based on the NMI handler - panic handlers get
installed as the NMI interrupt handler
- Changed symbol table generation: now use nm's own demangling and
sorting, and include symbol size in the table
- Move the linker script argument out of the kernel target, and into the
kernel's specific module, so that other programs (ie, panic handlers)
can use the kernel target as well
- Some asm changes to boot.s to help GDB see stack frames - but this
might not actually be all that useful
- Renamed user_rsp to just rsp in cpu_state - everything in there is
describing the 'user' state
Now that the other CPUs have been brought up, add support for scheduling
tasks on them. The scheduler now maintains separate ready/blocked lists
per CPU, and CPUs will attempt to balance load via periodic work
stealing.
Other changes as a result of this:
- The device manager no longer creates a local APIC object, but instead
just gathers relevant info from the APCI tables. Each CPU creates its
own local APIC object. This also spurred the APIC timer calibration to
become a static value, as all APICs are assumed to be symmetrical.
- Fixed a bug where the scheduler was popping the current task off of
its ready list, however the current task is never on the ready list
(except the idle task was first set up as both current and ready).
This was causing the lists to get into bad states. Now a task can only
ever be current or in a ready or blocked list.
- Got rid of the unused static process::s_processes list of all
processes, instead of trying to synchronize it via locks.
- Added spinlocks for synchronization to the scheduler and logger
objects.
Because the firmware can set the APIC ids to whatever it wants, add a
sequential index to each cpu_data structure that jsix will use for its
main identifier, or for indexing into arrays, etc.
In order to avoid cyclic dependencies in the case of page faults while
bringing up an AP, pre-allocate the cpu_data structure and related CPU
control structures, and pass them to the AP startup code.
This also changes the following:
- cpu_early_init() was split out of cpu_early_init() to allow early
usage of current_cpu() on the BSP before we're ready for the rest of
cpu_init(). (These functions were also renamed to follow the preferred
area_action naming style.)
- isr_handler now zeroes out the IST entry for its vector instead of
trying to increment the IST stack pointer
- the IST stacks are allocated outside of cpu_init, to also help reduce
stack pressue and chance of page faults before APs are ready
- share stack areas between AP idle threads so we only waste 1K per
additional AP for the unused idle stack
This very large commit is mainly focused on getting the APs started and
to a state where they're waiting to have work scheduled. (Actually
scheduling on them is for another commit.)
To do this, a bunch of major changes were needed:
- Moving a lot of the CPU initialization (including for the BSP) to
init_cpu(). This includes setting up IST stacks, writing MSRs, and
creating the cpu_data structure. For the APs, this also creates and
installs the GDT and TSS, and installs the global IDT.
- Creating the AP startup code, which tries to be as position
independent as possible. It's copied from its location to 0x8000 for
AP startup, and some of it is fixed at that address. The AP startup
code jumps from real mode to long mode with paging in one swell foop.
- Adding limited IPI capability to the lapic class. This will need to
improve.
- Renaming cpu/cpu.* to cpu/cpu_id.* because it was just annoying in GDB
and really isn't anything but cpu_id anymore.
- Moved all the GDT, TSS, and IDT code into their own files and made
them classes instead of a mess of free functions.
- Got rid of bsp_cpu_data everywhere. Now always call the new
current_cpu() to get the current CPU's cpu_data.
- Device manager keeps a list of APIC ids now. This should go somewhere
else eventually, device_manager needs to be refactored away.
- Moved some more things (notably the g_kernel_stacks vma) to the
pre-constructor setup in memory_bootstrap. That whole file is in bad
need of a refactor.
In order to allow the bootloader to do preliminary CPUID validation
while UEFI is still handling displaying information to the user, split
most of the kernel's CPUID handling into a library to be used by both
kernel and boot.
Implement the syscalls necessary for threads to create other threads in
their same process. This involved rearranging a number of syscalls, as
well as implementing object_wait and a basic implementation of a
process' list of handles.
Introduces the cpu_features.inc table to enumerate the CPU features that
j6 cares about. Features in this table marked CPU_FEATURE_REQ are
considered required, and the boot process will log an error and halt
when any of these features are not supported. This should save me from
banging my head against the wall like I did last night with the missing
pdpe1gb feature.
