Code paths that automatically allocate memory from the FBMS at 40:13
should also free it, if possible.
Freeing this memory will not be possible if either
1. The FBMS has been modified since our allocation, or
2. We have not been able to unhook one or more BIOS interrupt vectors.
We have EFI APIs for CPU I/O, PCI I/O, timers, console I/O, user
access and user memory allocation.
EFI executables are created using the vanilla GNU toolchain, with the
EXE header handcrafted in assembly and relocations generated by a
custom efilink utility.
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.
Wyse Streaming Manager server (WLDRM13.BIN) assumes that the PXENV+
entry point is at UNDI_CS:0000; apparently, somebody at Wyse has
difficulty distinguishing between the words "may" and "must"...
Add a dummy entry point at UNDI_CS:0000, which just jumps to the
correct entry point.
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.
Shifting all INT13 drive numbers causes problems on systems that use a
sparse drive number space (e.g. qemu BIOS, which uses 0xe0 for the CD-ROM
drive).
The strategy now is:
Each drive is assigned a "natural" drive number, being the next
available drive number in the system (based on the BIOS drive count).
Each drive is accessed using its specified drive number. If the
specified drive number is -1, the natural drive number will be used.
Accesses to the specified drive number will be delivered to the
emulated drive, masking out any preexisting drive using this number.
Accesses to the natural drive number, if different, will be remapped to
the masked-out drive.
The overall upshot is that, for examples:
System has no drives. Emulated INT13 drive gets natural number 0x80
and specified number 0x80. Accesses to drive 0x80 go to the emulated
drive, and there is no remapping.
System has one drive. Emulated INT13 drive gets natural number 0x81
and specified number 0x80. Accesses to drive 0x80 go to the emulated
drive. Accesses to drive 0x81 get remapped to the original drive 0x80.
__from_data16 and __from_text16 now take a pointer to a
.data16/.text16 variable, and return the real-mode offset within the
appropriate segment. This matches the use case for every occurrence
of these macros, and prevents potential future bugs such as that fixed
in commit d51d80f. (The bug arose essentially because "&pointer" is
still syntactically valid.)
This allows pxelinux to execute arbitrary gPXE commands. This is
remarkably unsafe (not least because some of the commands will assume
full ownership of memory and do nasty things like edit the e820 map
underneath the calling pxelinux), but it does allow access to the
"sanboot" command.
defined in vsprintf.h. (This may change, since vsprintf.h is a
non-standard name, but for now it's the one to use.)
There should be no need to include vsprintf.h just for DBG() statements,
since include/compiler.h forces it in for a debug build anyway.
Updated PXE API dispatcher to use copy_{to,from}_user, and moved to
arch/i386 since the implementation is quite architecture-dependent.
(The individual PXE API calls can be largely
architecture-independent.)
Allow our functions to return a non-zero, non-error status (since the
INT 13 Extensions Check has to return the API version in the register
that is otherwise always used for the error code).
Report a non-zero API version from the INT 13 Extensions Check; GRUB
now uses extended reads.
Michael Brown