[i386] Change semantics of __from_data16 and __from_text16
__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.)
[a20] Send a null command to the KBC after changing A20
Send a null command, specifically "pulse outputs" with no outputs
selected, to the KBC after changing A20. This was apparently done by DOS,
presumably as a synchronization hack, and the authors of the UHCI spec
thought it was inherent. Therefore, there are systems out there (e.g. HP
DL360 G5) which will stop responsing to "legacy USB" unless they see the
null command, 0xFF, written to port 0x64 at the end of the A20 toggling
sequence.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
A bug in read_smbios_string() was causing the starting offset of the
SMBIOS structure to be added twice, resulting in completely the wrong
strings being returned.
Bug identified by Martin Herweg <m.herweg@gmx.de>
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>
Ensure that empty e820 regions are skipped even at the end of the
memory map. (We achieve this by setting CF on the last entry if it is
zero-length; this avoids the need to look ahead to see at each entry
if the *next* entry would be both the last entry and zero-length).
This fixes the "0kB base memory" error message upon starting Windows
2003 on a SunFire X2100.
Ensure that empty e820 regions are skipped even at the end of the
memory map. (We achieve this by setting CF on the last entry if it is
zero-length; this avoids the need to look ahead to see at each entry
if the *next* entry would be both the last entry and zero-length).
This fixes the "0kB base memory" error message upon starting Windows
2003 on a SunFire X2100.
Use fast in-situ test for gate A20 being set, to cut down on the
number of (potentially very slow) gateA20_set operations.
Die with a fatal error if we are unable to set gate A20; if this fails
then we are bound to experience memory corruption at a later stage,
and I'd prefer to pick it up early.
Avoid draining the keyboard buffer during gateA20_set(). It shouldn't
technically be necessary, because the "enable A20" command requires
only that the keyboard controller is ready to accept input (i.e. that
its input buffer is empty), and shouldn't also require that the
keyboard is ready to send output (i.e. that its output buffer is also
empty). See http://www.smsc.com/main/tools/io-bios/42i.pdf section
3.1 ("Command Invocation") for a justification.
gateA20_set() is called on every real-mode transition (in case some
idiot piece of external code such as Intel's PXE stack decided it
would be fun to re-disable A20), so draining the keyboard buffer means
that we end up losing keypresses on some systems. In particular, this
makes typing at the command line almost impossible, and causes
Etherboot to ignore Ctrl-Alt-Del.
We should really implement a gateA20_test() function to verify that
gate A20 has been correctly enabled, and think about adding other
commonly-used methods such as Fast Gate A20.
We don't actually have a stdio.h header file. Our printf() functions are
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.
Check to see if we've reached the end of the map before attempting to
skip past an empty region, otherwise we end up generating an infinitely
long e820 map. (Yes, there *are* real systems that provide e820 maps
with a zero-length region at the end...)
Michael Brown