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
On my laptop, a few symbol names raise errors as invalid when attempting
to demangle them. This should not stop the rest of the symbol table from
building.
Create a script that builds a simple-to-read symbol table from the
output of `nm`. Include running that script over the kernel in the
build, and including that output in the initrd.
Tags: callstack debugging
