[settings] Add the notion of a "tag magic" to numbered settings
Settings can be constructed using a dotted-decimal notation, to allow
for access to unnamed settings. The default interpretation is as a
DHCP option number (with encapsulated options represented as
"<encapsulating option>.<encapsulated option>".
In several contexts (e.g. SMBIOS, Phantom CLP), it is useful to
interpret the dotted-decimal notation as referring to non-DHCP
options. In this case, it becomes necessary for these contexts to
ignore standard DHCP options, otherwise we end up trying to, for
example, retrieve the boot filename from SMBIOS.
Allow settings blocks to specify a "tag magic". When dotted-decimal
notation is used to construct a setting, the tag magic value of the
originating settings block will be ORed in to the tag number.
Store/fetch methods can then check for the magic number before
interpreting arbitrarily-numbered settings.
[pcbios] Guard against register corruption in INT 15,e820 implementations
Someone at Dell must have a full-time job designing ways to screw up
implementations of INT 15,e820. This latest gem is courtesy of a Dell
Xanadu system, which arbitrarily decides to obliterate the contents of
%esi.
Preserve %esi, %edi and %ebp across calls to INT 15,e820, in case
someone tries a variation on this trick in future.
The userptr_t is now the fundamental type that gets used for conversions.
For example, virt_to_phys() is implemented in terms of virt_to_user() and
user_to_phys().
[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.
[pcbios] Allow for larger-than-20-byte buffers in e820mangler.S
Although the E820 API allows for a caller to provide only a 20-byte
buffer, there exists at least one combination (HP BIOS, 32-bit WinPE)
that relies on information found only in the "extended attributes"
field, which requires a 24-byte buffer.
Allow for up to a 64-byte E820 buffer, in the hope of coping with
future idiocies like this one.
[pcbios] Print INT 15,E820 extended attributes, if present
The ACPI specification defines an additional 4-byte field at offset 20
for an E820 memory map entry. This field is presumably optional,
since generally E820 gets given only a 20-byte buffer to fill.
However, the bits of this optional field are defined as:
bit 0 : region is enabled
bit 1 : region is non-volatile memory rather than RAM
so it seems as though callers that pass in only a 20-byte buffer may
be missing out on some rather important information.
Our INT 15,e820 code was setting %es=%ss (as part of the "look ahead
in the memory map" logic), but failing to restore %es afterwards.
This is a serious bug, but wasn't affecting many platforms because
almost all callers seem to set %es=%ss anyway.
[pcbios] Fetch INT 15,e820 entry directly into our e820 cache
Some BIOSes require us to pass in not only the continuation value (in
%ebx) as returned by the previous call to INT 15,e820 but also the
unmodified buffer (at %es:%di) as returned by the previous call to INT
15,e820. Apparently, someone thought it would be a worthwhile
optimisation to fill in only the low dword of the "length" field and
the low byte of the "type field", assuming that the buffer would
remain unaltered from the previous call.
This problem was being triggered by the "peek ahead" logic in
get_mangled_e820(), which would read the next entry into a temporary
buffer in order to be able to guarantee terminating the map with
%ebx=0 rather than CF=1. (Terminating with CF=1 upsets some Windows
flavours, despite being documented legal behaviour.)
Work around this problem by always fetching directly into our e820
cache; that way we can guarantee that the underlying call always sees
the previous buffer contents (and the same buffer address).
[pcbios] Add facility for testing arbitrary E820 memory maps
We seem to be having issues with various E820 memory maps. These
problems are often difficult to reproduce, requiring access to the
specific system exhibiting the problem.
Add a facility for hooking in a fake E820 map generator, using an
arbitrary map defined in a C array, solely in order to be able to test
the map-mangling code against arbitrary E820 maps.
[pcbios] Inhibit INT 15 memory map hiding on brain-dead BIOSes
Some really moronic BIOSes bring up the PXE stack via the UNDI loader
entry point during POST, and then don't bother to unload it before
overwriting the code and data segments. If this happens, we really
don't want to leave INT 15 hooked, because that will cause any loaded
OS to die horribly as soon as it attempts to fetch the system memory
map.
We use a heuristic to detect whether or not we are being loaded at the
top of free base memory. If we determine that we are being loaded at
some other arbitrary location in base memory, then we assume that it's
not safe to hook INT 15.
INT 15,e801 is capable of returning a memory range that extends to
4GB, so allow for this in the debug message that shows the data
returned by INT 15,e801.
[pcbios] Support arbitrary splits of the e820 memory map
Allow for an arbitrary number of splits of the system memory map via
INT 15,e820.
Features of the new map-mangling algorithm include:
Supports random access to e820 map entries.
Requires only sequential access support from the underlying e820
map, even if our caller uses random access.
Empty regions will always be stripped.
Always terminates with %ebx=0, even if the underlying map terminates
with CF=1.
Allows for an arbitrary number of hidden regions, with underlying
regions split into as many subregions as necessary.
Total size increase to achieve this is 193 bytes.
[pcbios] Prepare for multiple splits of hidden e820 memory regions
Define a list of N allowed memory regions, and split each underlying
e820 region into up to N subregions. Strip resulting empty regions
out of the map, avoiding using the "return with CF set to strip last
empty region" trick, because it seems that bootmgr.exe in Win2k8 gets
upset if the memory map is terminated with CF set.
This is an intermediate checkin that defines a single allowed memory
region covering the entire 64-bit address space, and uses the existing
map-mangling code on top of the new region-splitting code. This
sanitises the memory map to the point that Win2k8 is able to boot even
on a system that defines a final zero-length region at the 4GB mark.
I'm checking this in because it may be useful for future debugging
efforts to be able to run with the existing and known-working map
mangling code together with the map sanitisation capabilities of the
new map mangling code.
[iSCSI] Support Windows Server 2008 direct iSCSI installation
Add yet another ugly hack to iscsiboot.c, this time to allow the user to
inhibit the shutdown/removal of the iSCSI INT13 device (and the network
devices, since they are required for the iSCSI device to function).
On the plus side, the fact that shutdown() now takes flags to
differentiate between shutdown-for-exit and shutdown-for-boot means that
another ugly hack (to allow returning via the PXE stack on BIOSes that
have broken INT 18 calls) will be easier.
I feel dirty.
[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.
Michael Brown