[ELF] Add ability to boot ELF images generated by wraplinux and mkelfImage
Delete ELF as a generic image type. The method for invoking an
ELF-based image (as well as any tables that must be set up to allow it
to boot) will always depend on the specific architecture. core/elf.c
now only provides the elf_load() function, to avoid duplicating
functionality between ELF-based image types.
Add arch/i386/image/elfboot.c, to handle the generic case of 32-bit
x86 ELF images. We don't currently set up any multiboot tables, ELF
notes, etc. This seems to be sufficient for loading kernels generated
using both wraplinux and coreboot's mkelfImage.
Note that while Etherboot 5.4 allowed ELF images to return, we don't.
There is no callback mechanism for the loaded image to shut down gPXE,
which means that we have to shut down before invoking the image. This
means that we lose device state, protection against being trampled on,
etc. It is not safe to continue afterwards.
Replace a printf with a DBG in timer_rtdsc.c
Replace a printf in timer.c with assert
Return proper error codes from timer drivers
Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Timer subsystem initialization code in core/timer.c
Split the BIOS and RTDSC timer drivers from i386_timer.c
Split arch/i386/firmware/pcbios/bios.c into the RTSDC
timer driver and arch/i386/core/nap.c
Split the headers properly:
include/unistd.h - delay functions to be used by the
gPXE core and drivers.
include/gpxe/timer.h - the fimer subsystem interface
to be used by the timer drivers
and currticks() to be used by
the code gPXE subsystems.
include/latch.h - removed
include/timer.h - scheduled for removal. Some driver
are using currticks, which is
only for core subsystems.
Signed-off-by: Alexey Zaytsev <alexey.zaytsev@gmail.com>
Add the concept of a "user pointer" (similar to the void __user * in
the kernel), which encapsulates the information needed to refer to an
external buffer. Under normal operation, this can just be a void *
equivalent, but under -DKEEP_IT_REAL it would be a segoff_t equivalent.
Use this concept to avoid the need for bounce buffers in int13.c,
which reduces memory usage and opens up the possibility of using
multi-sector reads.
Extend the block-device API and the SCSI block device implementation
to support multi-sector reads.
Update iscsi.c to use user buffers.
Move the obsolete portions of realmode.h to old_realmode.h.
MS-DOS now boots an order of magnitude faster over iSCSI (~10 seconds
from power-up to C:> prompt in bochs).