KernelHAL

Phantom HAL divides machine-dependent code in two parts: architecture dependent and board (specific kind of hardware) dependent.

See Machine dependent headers, Toolchain setup

What architecture and board we build for is defined in local-config.mk (see local-config.mk.in for ref)

ARCH=e2k
BOARD=some_elbrus_board_name

Machine dependent code directories:

include/e2k
oldtree/kernel/phantom/e2k # arch (CPU) dependent code comes here
oldtree/kernel/phantom/e2k/some_elbrus_board_name # specific hardware conf dependent code comes here

phantom/dev/e2k - specfic arch drivers come here

phantom/libc/e2k - asm code for libc comes here

phantom/libkern/e2k - see sibling folders
phantom/libphantom/e2k - see sibling folders
phantom/threads/e2k - context switch, cpu state, etc

phantom/Makeconf-e2k - toolchain setup (names of binaries to build and link)
oldtree/kernel/Makeconf-e2k - toolchain

oldtree/kernel/phantom/ARCH

entry.S - kernel entry point and basic hardware init

Must init hardware to the state when C code can be run.

After that phantom_multiboot_main function must be called to init kernel.

phantom_multiboot_main inits:

• CPU (not MMU)
• interrupts
• boot console
• low level address map (physical memory management)
• kernel heap
• kernel arguments (command line)
• run constructors

by calling corresponding init functions and calls main() finally.

arch_init_early() and board_init_early()

Called just after assembly code init is done to make architecture specific and board specific initializations. Can be empty.

spinlock.c

Basic spinlocks:

• hal_spin_init/lock/unlock - as is
• check_global_lock_entry_count - called in sutuations when kernel expects that no spin lock is locked to check that

paging.c

hal_page_control_etc - map or unmap virtual memory page according to parameters given

sched.c

phantom_scheduler_request_soft_irq - must schedule soft IRQ for threads subsystem (hal_request_softirq(SOFT_IRQ_THREADS);) and cause any interrupt then.