QEMU will silently round down a disk or ROM image file to the nearest
512 bytes. Fix by always padding .rom, .dsk and .hd images to the
nearest 512-byte boundary.
Originally-fixed-by: Stefan Hajnoczi <stefanha@gmail.com>
Using "lret $2" to return from an interrupt causes interrupts to be
disabled in the calling program, since the INT instruction will have
disabled interrupts. Instead, patch CF on the stack and use iret to
return.
Interestingly, the original PC BIOS had this bug in at least one
place.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Michael Brown <mcb30@etherboot.org>
This allows gPXE to load memtest86, which is packaged as an old kernel.
Split all code that directly touches the kernel headers out into
bzimage_parse_header() and bzimage_update_header(), to reduce code
size and offset the cost of supporting older kernels.
Total cost of this feature: 11 bytes (uncompressed).
The parsing of the !PXE and PXENV+ structures share a fair bit of
code; merge the common code to save a few bytes.
Signed-off-by: Michael Brown <mcb30@etherboot.org>
Search for the PXE entry points (via the !PXE or PXENV+ structures)
through all known combinations of search methods. Furthermore, if we
find a PXENV+ structure, attempt to use it to find the !PXE structure
if at all possible.
Avoid passing credentials in the iBFT that were available but not
required for login. This works around a problem in the Microsoft
iSCSI initiator, which will refuse to initiate sessions if the CHAP
password is fewer than 12 characters, even if the target ends up not
asking for CHAP authentication.
The PXE 1.x spec specifies that on NBP entry or on return from INT
1Ah AX=5650h, EDX shall point to the physical address of the PXENV+
structure. The PXE 2.x spec drops this requirement, simply stating
that EDX is clobbered. Given the principle "be conservative in what
you send, liberal in what you accept", however, we should implement
this anyway.
Certain combinations of PXE stack and BIOS result in a broken INT 18
call, which will leave the system displaying a "PRESS ANY KEY TO
REBOOT" message instead of proceeding to the next boot device. On
these systems, returning via the PXE stack is the only way to continue
to the next boot device. Returning via the PXE stack works only if we
haven't already blown away the PXE base code in pxeprefix.S.
In most circumstances, we do want to blow away the PXE base code.
Base memory is a limited resource, and it is desirable to reclaim as
much as possible. When we perform an iSCSI boot, we need to place the
iBFT above the 512kB mark, because otherwise it may not be detected by
the loaded OS; this may not be possible if the PXE base code is still
occupying that memory.
Introduce a new prefix type .kkpxe which will preserve both the PXE
base code and the UNDI driver (as compared to .kpxe, which preserves
the UNDI driver but uninstalls the PXE base code). This prefix type
can be used on systems that are known to experience the specific
problem of INT 18 being broken, or in builds (such as gpxelinux.0) for
which it is particularly important to know that returning to the BIOS
will work.
Written by H. Peter Anvin <hpa@zytor.com> and Stefan Hajnoczi
<stefanha@gmail.com>, minor structural alterations by Michael Brown
<mcb30@etherboot.org>.
COMBOOT images use INTs to issue API calls; these end up making calls
into gPXE from real mode, and so temporarily change the real-mode
stack pointer. When our COMBOOT code uses a longjmp() to implement
the various "exit COMBOOT image" API calls, this leaves the real-mode
stack pointer stuck with its temporary value, which causes problems if
we eventually try to exit out of gPXE back to the BIOS.
Fix by adding rmsetjmp() and rmlongjmp() calls (analogous to
sigsetjmp()/siglongjmp()); these save and restore the additional state
needed for real-mode calls to function correctly.
Multi-level menus via COMBOOT rely on the COMBOOT program being able
to exit and invoke a new COMBOOT program (the next menu). This works,
but rapidly (within about five iterations) runs out of space in gPXE's
internal stack, since each new image is executed in a new function
context.
Fix by allowing tail recursion between images; an image can now
specify a replacement image for itself, and image_exec() will perform
the necessary tail recursion.
The version of the GNU assembler shipped with Fedora 10
(2.18.50.0.9-8.fc10) complains about character literals in some of our
assembly code. Changing $'x' to $( 'x' ) seems to fix the problem.
Yes, the whitespace is required; using just $('x') does not work.
Reported by Kevin O'Connor <kevin@koconnor.net>.
There are code paths other than PMM allocation that can result in our
changing the ROM checksum. For example, we attempt to update our
product string to incorporate the PCI bus:dev.fn number. In a system
that does not support PMM, we could therefore end up with an incorrect
checksum.
Fix by attempting to update the checksum unconditionally.
As reported by Stefan, commit 13d09e6 ("[i386] Simplify linker script
and standardise linker-defined symbol names") breaks gdb, readelf and
associated utilities.
This is caused by the .stack section overwriting a block in the middle
of the .debug_info section (despite being included in the
.bss.textdata section in the output file, which apparently has the
correct attributes for a .bss section).
Fixed by adding explicit flags and type to the stack section
declaration.
If it happens that _textdata_memsz ends up being an exact multiple of
4kB, then this will cause the .textdata section (after relocation) to
start on a page boundary. This means that the hidden memory region
(which is rounded down to the nearest page boundary) will start
exactly at virtual address 0, i.e. UNULL. This means that
init_eheap() will erroneously assume that it has failed to allocate a
an external heap, since it typically ends up choosing the area that
lies immediately below .textdata, which in this case will be the
region with top==UNULL.
A subsequent error is that memtop_urealloc() passes through the error
return status -ENOMEM to the caller, which (rightly) assumes that the
result represents a valid userptr_t address.
Fixed by using alternative tests for heap non-existence, and by
returning UNULL in case of an error from init_eheap().
There are many functions that take ownership of the I/O buffer they
are passed as a parameter. The caller should not retain a pointer to
the I/O buffer. Use iob_disown() to automatically nullify the
caller's pointer, e.g.:
xfer_deliver_iob ( xfer, iob_disown ( iobuf ) );
This will ensure that iobuf is set to NULL for any code after the call
to xfer_deliver_iob().
iob_disown() is currently used only in places where it simplifies the
code, by avoiding an extra line explicitly setting the I/O buffer
pointer to NULL. It should ideally be used with each call to any
function that takes ownership of an I/O buffer. (The SSA
optimisations will ensure that use of iob_disown() gets optimised away
in cases where the caller makes no further use of the I/O buffer
pointer anyway.)
If gcc ever introduces an __attribute__((free)), indicating that use
of a function argument after a function call should generate a
warning, then we should use this to identify all applicable function
call sites, and add iob_disown() as necessary.
The DHCP client code now implements only the mechanism of the DHCP and
PXE Boot Server protocols. Boot Server Discovery can be initiated
manually using the "pxebs" command. The menuing code is separated out
into a user-level function on a par with boot_root_path(), and is
entered in preference to a normal filename boot if the DHCP vendor
class is "PXEClient" and the PXE boot menu option exists.
pxe_tftp.c assumes that the first seek on its data-transfer interface
represents the block size. Apart from being an ugly hack, this will
also screw up file size calculation for files smaller than one block.
The proper solution would be to extend the data-transfer interface to
support the reporting of stat()-like data. This is not going to
happen until the cost of adding interface methods is reduced (a fix I
have planned since June 2008).
In the meantime, abuse the xfer_window() method to return the block
size, since it is not being used for anything else and is vaguely
justifiable.
Astonishingly, having returned the incorrect TFTP blocksize via
PXENV_TFTP_OPEN for almost a year seems not to have affected any of
the test cases run during that time; this bug was found only when
someone tried running the heavily-patched version of pxegrub found in
OpenSolaris.
elf2efi converts a suitable ELF executable (containing relocation
information, and with appropriate virtual addresses) into an EFI
executable. It is less tightly coupled with the gPXE build process
and, in particular, does not require the use of a hand-crafted PE
image header in efiprefix.S.
elf2efi correctly handles .bss sections, which significantly reduces
the size of the gPXE EFI executable.
The check for unresolved symbols does not explicitly specify an output
architecture format, and so causes a warning when building an i386 EFI
binary on an x86_64 platform. This warning is harmless, and
specifying the output architecture in multiple places is cumbersome,
so just inhibit the warning.
At POST time some BIOSes return invalid e820 maps even though
they indicate that the data is valid. We add a check that the first
region returned by e820 is RAM type and declare the map to be invalid
if it is not.
This extends the sanity checks from 8b20e5d ("[pcbios] Sanity-check
the INT15,e820 and INT15,e801 memory maps").
Currently the only supported platform for x86_64 is EFI.
Building an EFI64 gPXE requires a version of gcc that supports
__attribute__((ms_abi)). This currently means a development build of
gcc; the feature should be present when gcc 4.4 is released.
In the meantime; you can grab a suitable gcc tree from
git://git.etherboot.org/scm/people/mcb30/gcc/.git
EFI provides a copy of the SMBIOS table accessible via the EFI system
table, which we should use instead of manually scanning through the
F000:0000 segment.
On non-BBS systems, we have to hook INT 19 in order to be able to boot
from the gPXE ROM at all. However, doing this unconditionally will
prevent the user from booting via any other devices.
Previously, the INT 19 entry point would prompt the user to press B in
order to boot from gPXE, which makes it impossible to perform an
unattended network boot. We now prompt the user to press N to skip
booting from gPXE, which allows for unattended operation.
This should be a better match for most real-world scenarios. Most
modern systems support BBS and so are unaffected by this change. Very
old (non-BBS) systems tend not to have PXE ROMs by default anyway; if
the user has added a gPXE ROM then they probably do want to boot from
the network. Newer non-BBS systems are essentially limited to IBM
servers, which will recapture the INT 19 vector anyway and implement
their own boot-ordering selection mechanism.
Remove the assortment of miscellaneous hacks to guess the "network
boot device", and replace them each with a call to last_opened_netdev().
It still isn't guaranteed correct, but it won't be any worse than
before, and it will at least be consistent.
This brings us in to line with Linux definitions, and also simplifies
adding x86_64 support since both platforms have 2-byte shorts, 4-byte
ints and 8-byte long longs.
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.
_filesz was incorrectly forced to be aligned up to MAX_ALIGN. In a
non-compressed build, this would cause a build failure unless _filesz
happened to already be aligned to MAX_ALIGN.
The only way that PMM allows us to request a block in a region with
A20=0 is to ask for a block with an alignment of 2MB. Due to the PMM
API design, the only way we can do this is to ask for a block with a
size of 2MB.
Unfortunately, some BIOSes will hit problems if we allocate a 2MB
block. In particular, it may not be possible to enter the BIOS setup
screen; the BIOS setup code attempts a PMM allocation, fails, and
hangs the machine.
We now try allocating only as much as we need via PMM. If the
allocated block has A20=1, we free the allocated block, double the
allocation size, and try again. Repeat until either we obtain a block
with A20=0 or allocation fails. (This is guaranteed to terminate by
the time we reach an allocation size of 2MB.)
With a 16-bit operand, lgdt/lidt will load only a 24-bit base address,
ignoring the high-order bits. This meant that we could fail to fully
restore the GDT across a call into gPXE, if the GDT happened to be
located above the 16MB mark.
Not all of our lgdt/lidt instructions require a data32 prefix (for
example, reloading the real-mode IDT can never require a 32-bit base
address), but by adding them everywhere we will hopefully not forget
the necessary ones in future.
Some hardware vendors have been known to remove all gPXE-related
branding from ROMs that they build. While this is not prohibited by
the GPL, it is a little impolite.
Add a facility for adding branding messages via two #defines
(PRODUCT_NAME and PRODUCT_SHORT_NAME) in config/general.h. This
should accommodate all known OEM-mandated branding requirements.
Vendors with branding requirements that cannot be satisfied by using
PRODUCT_NAME and/or PRODUCT_SHORT_NAME should contact us so that we
can extended this facility as necessary.
This function is a major kludge, but can be made slightly more
accurate by ignoring net devices that aren't open. Eventually it
needs to be removed entirely.
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.
This extends the sanity checks on the runtime segment address provided
in %bx, first implemented in commit 5600955.
We now allow the ROM to be placed anywhere above a000:0000 (rather
than c000:0000, as before), since this is the region allowed by the
PCI 3 spec. If the BIOS asks us to place the runtime image such that
it would overlap with the init-time image (which is explicitly
prohibited by the PCI 3 spec), then we assume that the BIOS is faulty
and ignore the provided runtime segment address.
Testing on a SuperMicro BIOS providing overlapping segment addresses
shows that ignoring the provided runtime segment address is safe to do
in these circumstances.
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.
FreeBSD requires the object format to be specified as elf_i386_fbsd,
rather than elf_i386.
Based on a patch from Eygene Ryabinkin <rea-fbsd@codelabs.ru>
Some PCI 3 BIOSes seem to provide a garbage value in %bx, which should
contain the runtime segment address. Perform a basic sanity check: we
reject the segment if it is below the start of option ROM space. If
the sanity check fails, we assume that the BIOS was not expecting us
to be a PCI 3 ROM, and we just leave our image in situ.
The section name seems to have significance for some versions of
binutils.
There is no way to instruct gcc that sections such as .bss16 contain
uninitialised data; it will emit them with contents explicitly set to
zero. We therefore have to rely on the linker script to force these
sections to become uninitialised-data sections. We do this by marking
them as NOLOAD; this seems to be the closest semantic equivalent in the
linker script language.
However, this gets ignored by some versions of ld (including 2.17 as
shipped with Debian Etch), which mark the resulting sections with
(CONTENTS,ALLOC,LOAD,DATA). Combined with the fact that this version of
ld seems to ignore the specified LMA for these sections, this means that
they end up overlapping other sections, and so parts of .prefix (for
example) get obliterated by .data16's bss section.
Rename the .bss sections from .section_bss to .bss.section; this seems to
cause these versions of ld to treat them as uninitialised data.
Not fully understood, but it seems that the LMA of bss sections matters
for some newer binutils builds. Force all bss sections to have an LMA
at the end of the file, so that they don't interfere with other
sections.
The symptom was that objcopy -O binary -j .zinfo would extract the
.zinfo section from bin/xxx.tmp as a blob of the correct length, but
with zero contents. This would then cause the [ZBIN] stage of the
build to fail.
Also explicitly state that .zinfo(.*) sections have @progbits, in case
some future assembler or linker variant decides to omit them.
Some versions of ld choke on the "AT ( _xxx_lma )" in efi.lds with an
error saying "nonconstant expression for load base". Since these were
only explicitly setting the LMA to the address that it would have had
anyway, they can be safely omitted.
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.
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().
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.
Allow for the build CPU architecture and platform to be specified as part
of the make command goals. For example:
make bin/rtl8139.rom # Standard i386 PC-BIOS build
make bin-efi/rtl8139.efi # i386 EFI build
The generic syntax is "bin[-[arch-]platform]", with the default
architecture being "i386" (regardless of the host architecture) and the
default platform being "pcbios".
Non-path targets such as "srcs" can be specified using e.g.
make bin-efi srcs
Note that this changeset is merely Makefile restructuring to allow the
build architecture and platform to be determined by the make command
goals, and to export these to compiled code via the ARCH and PLATFORM
defines. It doesn't actually introduce any new build platforms.
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.
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.
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).
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.
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.
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.
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.
If the INT 15,e820 memory map reports a region [0,0), this confuses
the "truncate to even megabytes" logic, which ends up rounding the
region 'down' to [0,fff00000).
Fix by ensuring that the region's end address is at least 1, before we
subtract 1 to obtain the "last byte in region" address.
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.
Apparently some BIOSes will place option ROMs on 512-byte boundaries.
While this is against specification, it doesn't actually hurt
anything, so we may as well increase our scan granularity to 512
bytes.
Contributed by Luca <lucarx76@gmail.com>
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.
The multiboot specification states that, for raw images, if
load_end_addr is zero then it should be interpreted as meaning "use
the entire file", and if bss_end_addr is zero it should be interpreted
as meaning "no bss".
Explicitly state that we are using 32-bit addressing in 16-bit code.
GNU as 2.15 (FreeBSD/amd64 7-STABLE) got confused that 32-bit registers
are used in the code that was declared as 16-bit. Add explicit modifier
'addr32' to make assembler happy.
Signed-off-by: Eygene Ryabinkin <rea-fbsd@codelabs.ru>
