Restructuring paging into an object that carries its page cache with it
and makes for simpler code. Program loading is also changed to not copy
the pages loaded from the file into new pages - we can impose a new
constraint that anything loaded by boot have a simple, page-aligned
layout so that we can just map the existing pages into the right
addresses. Also included are some linker script changes to help
accommodate this.
This new libc is mostly from scratch, with *printf() functions provided
by Marco Paland and Eyal Rozenberg's tiny printf library, and malloc and
friends provided by dlmalloc.
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
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
Continuing moving things out of kutil. The assert as implemented could
only ever work in the kernel, so remaining kutil uses of kassert have
been moved to including standard C assert instead.
Along the way, kassert was broken out into panic::panic and kassert,
and the panic.serial namespace was renamed panicking.
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
- More sensible stack tracer, in C++ (no symbols yet)
- Was forgetting to add null frame to new kernel stacks
- __kernel_assert was using an old vector
- A GP fault will only print its associated table entry
