[i386] Simplify linker script and standardise linker-defined symbol names
Reduce the number of sections within the linker script to match the
number of practical sections within the output file.
Define _section, _msection, _esection, _section_filesz, _section_memsz,
and _section_lma for each section, replacing the mixture of symbols that
previously existed.
In particular, replace _text and _end with _textdata and _etextdata, to
make it explicit within code that uses these symbols that the .text and
.data sections are always treated as a single contiguous block.
[romprefix] Allow BANNER_TIMEOUT to control banners in romprefix.S
In particular, allow BANNER_TIMEOUT=0 to inhibit the prompt banners
altogether.
Ironically, this request comes from the same OEM that originally
required the prompts to be present during POST.
[romprefix] If we hook INT 19, prompt before attempting boot
On non-BBS systems we hook INT 19, since there is no other way we can
guarantee gaining control of the flow of execution. If we end up
doing this, prompt the user before attempting boot, since forcibly
capturing INT 19 is rather antisocial.
IBM's iSCSI Firmware Initiator checks the UNDIROMID pointer in the
!PXE structure that gets created by the UNDI loader. We didn't
previously fill this value in.
[romprefix] Add more diagnostic messages to ROM prefix
Include PMM allocation result in POST banner.
Include full product string in "starting execution" message.
Also mark ourselves as supporting DDIM in PnP header, for
completeness.
[romprefix] On a PCI3.0, non-BBS system, use the correct %cs for INT19
On a system that doesn't support BBS, we end up hooking INT19 to gain
control of the boot process. If the system is PCI3.0, we must take
care to use the runtime value for %cs, rather than the POST-time
value, otherwise we end up pointing INT19 to the temporary option ROM
POST scratch area.
Commit fd0aef9 introduced a typo that caused PMM detection to start at
paragraph 0xe00 rather than 0xe000. (Detection would still work, since it
would scan until it ran out of base memory, but it would end up scanning
an unnecessarily large portion of base memory.)
Spotted by Sebastian Herbszt <herbszt@gmx.de>.
[prefix] When we have to hook INT 19, chain to original handler if possible
When the BIOS doesn't support BBS, hooking INT 19 is the only way to add
ourselves as a boot device. If we have to do this, we should at least
try to chain to the original INT 19 vector if our boot fails.
Idea suggested by Andrew Schran <aschran@google.com>
[prefix] Prompt for entering gPXE shell during POST
The ROM prefix now prompts the user to enter the gPXE shell during POST;
this allows for configuring gPXE without needing to attempt to boot from
it. (It also slows down system boot by three seconds per gPXE ROM, but
hey.)
This is apparently a certain OEM's requirement for option ROMs.
Use BBS installation check to see if we need to hook INT19 even on a PnP
BIOS.
Verify that $PnP signature is paragraph-aligned; bochs/qemu BIOS provides
a dummy $PnP signature with no valid entry point, and deliberately
unaligns the signature to indicate that it is not properly valid.
Print message if INT19 is hooked.
Attempt to use PMM even if BBS check failed.
ROM initialisation vector now attempts to allocate a 2MB block using
PMM. If successful, it copies the ROM image to this block, then
shrinks the ROM image to allow for more option ROMs. If unsuccessful,
it leaves the ROM as-is.
ROM BEV now attempts to return to the BIOS, resorting to INT 18 only
if the BIOS stack has been corrupted.
Michael Brown