Minimise code size by forcing the use of memory addresses for
__bswap_16s() and __bswap_64s(). (__bswap_32s() cannot avoid loading the
value into a register.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Fix a strict-aliasing error on certain versions of gcc.
Reported-by: Marko Myllynen <myllynen@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the "bswap" instruction to shrink the size of byte-swapping code,
and provide the in-place variants __bswap_{16,32,64}s.
"bswap" is available only on 486 and later processors. (We already
assume the presence of "cpuid" and "rdtsc", which are available only
on Pentium and later processors.)
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The RTC-based entropy source uses the nanosecond-scale CPU TSC to
measure the time between two 1kHz interrupts generated by the CMOS
RTC. In a physical machine these clocks are driven from independent
crystals, resulting in some observable clock drift. In a virtual
machine, the CMOS RTC is typically emulated using host-OS
constructions such as SIGALRM.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ANS X9.82 specifies several Approved Sources of Entropy Input (SEI).
One such SEI uses an entropy source as the Source of Entropy Input,
condensing each entropy source output after each GetEntropy call.
This can be implemented relatively cheaply in iPXE and avoids the need
to allocate potentially very large buffers.
(Note that the terms "entropy source" and "Source of Entropy Input"
are not synonyms within the context of ANS X9.82.)
Use the iPXE API mechanism to allow entropy sources to be selected at
compilation time.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
PXENV_FILE_EXIT_HOOK is designed to allow ipxelinux.0 to unload both
the iPXE and pxelinux components without affecting the underlying PXE
stack. Unfortunately, it causes unexpected behaviour in other
situations, such as when loading a non-embedded pxelinux.0 via
undionly.kpxe. For example:
PXE ROM -> undionly.kpxe -> pxelinux.0 -> chain.c32 to boot hd0
would cause control to return to iPXE instead of booting from the hard
disk. In some cases, this would result in a harmless but confusing
"No more network devices" message; in other cases stranger things
would happen, such as being returned to the iPXE shell prompt.
The fundamental problem is that when pxelinux detects
PXENV_FILE_EXIT_HOOK, it may attempt to specify an exit hook and then
exit back to iPXE, assuming that iPXE will in turn exit cleanly via
the specified exit hook. This is not a valid assumption in the
general case, since the action of exiting back to iPXE does not
directly cause iPXE to exit itself. (In the specific case of
ipxelinux.0, this will work since the embedded script exits as soon as
pxelinux.0 exits.)
Fix the unexpected behaviour in the non-ipxelinux.0 cases by including
support for PXENV_FILE_EXIT_HOOK only when using a new .kkkpxe format.
The ipxelinux.0 build process should therefore now use undionly.kkkpxe
instead of undionly.kkpxe.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow an initrd (such as an embedded script) to be passed to iPXE when
loaded as a .lkrn (or .iso) image. This allows an embedded script to
be varied without recompiling iPXE.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Expose the multiple-SAN-drive capability of the iPXE core via the iPXE
command line by adding commands to hook and unhook additional drives.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The disk signature is used by some OSes (notably Windows) to identify
the boot disk, so it's useful debugging information to have.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Support the extensions mandated by EDD 4.0, including:
o the ability to specify a flat physical address in a disk address
packet,
o the ability to specify a sector count greater than 127 in a disk
address packet,
o support for all functions within the Fixed Disk Access and EDD
Support subsets,
o the ability to describe a device using EDD Device Path Information.
This implementation is based on draft revision 3 of the EDD 4.0
specification, with reference to the EDD 3.0 specification. It is
possible that this implementation may need to change in order to
conform to the final published EDD 4.0 specification.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The block device interface used in gPXE predates the invention of even
the old gPXE data-transfer interface, let alone the current iPXE
generic asynchronous interface mechanism. Bring this old code up to
date, with the following benefits:
o Block device commands can be cancelled by the requestor. The INT 13
layer uses this to provide a global timeout on all INT 13 calls,
with the result that an unexpected passive failure mode (such as
an iSCSI target ACKing the request but never sending a response)
will lead to a timeout that gets reported back to the INT 13 user,
rather than simply freezing the system.
o INT 13,00 (reset drive) is now able to reset the underlying block
device. INT 13 users, such as DOS, that use INT 13,00 as a method
for error recovery now have a chance of recovering.
o All block device commands are tagged, with a numerical tag that
will show up in debugging output and in packet captures; this will
allow easier interpretation of bug reports that include both
sources of information.
o The extremely ugly hacks used to generate the boot firmware tables
have been eradicated and replaced with a generic acpi_describe()
method (exploiting the ability of iPXE interfaces to pass through
methods to an underlying interface). The ACPI tables are now
built in a shared data block within .bss16, rather than each
requiring dedicated space in .data16.
o The architecture-independent concept of a SAN device has been
exposed to the iPXE core through the sanboot API, which provides
calls to hook, unhook, boot, and describe SAN devices. This
allows for much more flexible usage patterns (such as hooking an
empty SAN device and then running an OS installer via TFTP).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
COM32 binaries generally expect to run with interrupts
enabled. Syslinux does so, and COM32 programs will execute cli/sti
pairs when running a critical section, to provide mutual exclusion
against BIOS interrupt handlers. Previously, under iPXE, the IDT was
not valid, so any interrupt (e.g. a timer tick) would generally cause
the machine to triple fault.
This change introduces code to:
- Create a valid IDT at the same location that syslinux uses
- Create an "interrupt jump buffer", which contains small pieces of
code that simply record the vector number and jump to a common
handler
- Thunk down to real mode and execute the BIOS's interrupt handler
whenever an interrupt is received in a COM32 program
- Switch IDTs and enable/disable interrupts when context switching to
and from COM32 binaries
Testing done:
- Booted VMware ESX using a COM32 multiboot loader (mboot.c32)
- Built with GDBSERIAL enabled, and tested breakpoints on int22 and
com32_irq
- Put the following code in a COM32 program:
asm volatile ( "sti" );
while ( 1 );
Before this change, the machine would triple fault
immediately. After this change, it hangs as expected. Under Bochs,
it is possible to see the interrupt handler run, and the current
time in the BIOS data area gets incremented.
Signed-off-by: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Most of iPXE uses __attribute__((packed)) anyway, and PACKED conflicts
with an identically-named macro in the upstream EFI header files.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
See RFC 4578 for details.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This removes the need for inline safety wrappers, marginally reducing
the size penalty of weak functions, and works around an apparent
binutils bug that causes undefined weak symbols to not actually be
NULL when compiling with -fPIE (as EFI builds do).
A bug in versions of binutils prior to 2.16 (released in 2005) will
cause same-file weak definitions to not work with those
toolchains. Update the README to reflect our new dependency on
binutils >= 2.16.
Signed-off-by: Joshua Oreman <oremanj@rwcr.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Microsoft WDS can end up calling PXENV_RESTART_TFTP to execute a
second-stage NBP which then exits. Specifically, wdsnbp.com uses
PXENV_RESTART_TFTP to execute pxeboot.com, which will exit if the user
does not press F12. iPXE currently treats PXENV_RESTART_TFTP as a
normal PXE API call, and so attempts to return to wdsnbp.com, which
has just been vaporised by pxeboot.com.
Use rmsetjmp/rmlongjmp to preserve the stack state as of the initial
NBP execution, and to restore this state immediately prior to
executing the NBP loaded via PXENV_RESTART_TFTP. This matches the
behaviour in the PXE spec (which says that "if TFTP is restarted,
control is never returned to the caller"), and allows pxeboot.com to
exit relatively cleanly back to iPXE.
As with all usage of setjmp/longjmp, there may be subtle corner case
bugs due to not gracefully unwinding any state accumulated by the time
of the longjmp call, but this seems to be the only viable way to
provide the specified behaviour.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the shared code in libflat to perform the A20 transitions
automatically on each transition from real to protected mode. This
allows us to remove all explicit calls to gateA20_set().
The old warnings about avoiding automatically enabling A20 are
essentially redundant; they date back to the time when we would always
start hammering the keyboard controller without first checking to see
if gate A20 was already enabled (which it almost always is).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Access to the gpxe.org and etherboot.org domains and associated
resources has been revoked by the registrant of the domain. Work
around this problem by renaming project from gPXE to iPXE, and
updating URLs to match.
Also update README, LOG and COPYRIGHTS to remove obsolete information.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
gPXE currently overwrites the filename stored in the cached DHCP
packets when a call to PXENV_TFTP_READ_FILE or PXENV_RESTART_TFTP is
made. This code has existed for many years as a workaround for RIS,
which seemed to require that this be done.
pxe_set_cached_filename() causes problems with the Bootix NBP, and a
recent test demonstrates that RIS will complete successfully even with
pxe_set_cached_filename() removed. There have been many changes to
the DHCP and PXE logic since this code was first added, and it is
quite plausible that it was masking a bug that no longer exists.
Reported-by: Alex Zeffertt <alex.zeffertt@eu.citrix.com>
Debugged-by: Shao Miller <Shao.Miller@yrdsb.edu.on.ca>
Signed-off-by: Michael Brown <mcb30@etherboot.org>
It might be the case that we wish to chain to an NBP without
being "in the way". We now implement a hook in our exit path
for gPXE *.*pxe build targets. The hook is a pointer to a
SEG16:OFF16 which we try to jump to during exit. By default,
this pointer results in the usual exit path.
We also implement the "pxenv_file_exit_hook" PXE API routine
to allow the user to specify an alternate SEG16:OFF16 to jump
to during exit.
Unfortunately, this additional PXE extension has a cost
in code size. Fortunately, a look at the size difference
for a gPXE .rom build target shows zero size difference
after compression.
The routine is documented in doc/pxe_extensions as follows:
FILE EXIT HOOK
Op-Code: PXENV_FILE_EXIT_HOOK (00e7h)
Input: Far pointer to a t_PXENV_FILE_EXIT_HOOK parameter
structure that has been initialized by the caller.
Output: PXENV_EXIT_SUCCESS or PXENV_EXIT_FAILURE must be
returned in AX. The Status field in the parameter
structure must be set to one of the values represented
by the PXENV_STATUS_xxx constants.
Description:Modify the exit path to jump to the specified code.
Only valid for pxeprefix-based builds.
typedef struct s_PXENV_FILE_EXIT_HOOK {
PXENV_STATUS_t Status;
SEGOFF16_t Hook;
} t_PXENV_FILE_EXIT_HOOK;
Set before calling API service:
Hook: The SEG16:OFF16 of the code to jump to.
Returned from API service:
Status: See PXENV_STATUS_xxx constants.
Requested-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Shao Miller <shao.miller@yrdsb.edu.on.ca>
Signed-off-by: Marty Connor <mdc@etherboot.org>
For extremely tight space requirements and specific applications, it is
sometimes desirable to create gPXE images that cannot provide the PXE API
functionality to client programs. Add a configuration header option,
PXE_STACK, that can be removed to remove this stack. Also add PXE_MENU
to control the PXE boot menu, which most uses of gPXE do not need.
Signed-off-by: Marty Connor <mdc@etherboot.org>
Calling the parent PXE stack (the stack that loaded us, for
undionly.kkpxe) can be useful for more than UNDI calls; for instance,
it lets us get cached DHCP packets to avoid re-DHCP when working with
embedded images.
Signed-off-by: Marty Connor <mdc@etherboot.org>
The SRP Boot Firmware Table serves a similar role to the iSCSI and AoE
Boot Firmware Tables; it provides information required by the loaded
OS in order to establish a connection back to the SRP boot device.
pxe_api.h is just a description of API functions, it's actively
undesirable to have more implementations than necessary. Allowing it
under the MIT license lets the Syslinux libraries use it.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Michael Brown <mcb30@etherboot.org>
pxe_init_structures() fills in the fields of the !PXE and PXENV+
structures that aren't known until gPXE starts up. Once gPXE is
started, these values will never change.
Make pxe_init_structures() an initialisation function so that PXE
users don't have to worry about calling it.
The Intel DOS UNDI driver fails when run on top of gPXE because we do
not fill in the ServiceFlags field in PXENV_UNDI_GET_IFACE_INFO.
Fix by filling in the ServiceFlags field with reasonable values
indicating our approximate feature capabilities.
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).
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.
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.
Michael Brown