When booting iPXE from a filesystem (e.g. a FAT-formatted USB key) it
can be useful to have an iPXE script loaded automatically from the
same filesystem. Compared to using an embedded script, this has the
advantage that the script can be edited without recompiling the iPXE
binary.
For the BIOS version of iPXE, loading from a filesystem is handled
using syslinux (or isolinux) which allows the script to be passed to
the iPXE .lkrn image as an initrd.
For the UEFI version of iPXE, the platform firmware loads the iPXE
.efi image directly and there is currently no equivalent of the BIOS
initrd mechanism.
Add support for automatically loading a file "autoexec.ipxe" (if
present) from the root of the filesystem containing the UEFI iPXE
binary.
A combined BIOS and UEFI image for a USB key can be created using e.g.
./util/genfsimg -o usbkey.img -s myscript.ipxe \
bin-x86_64-efi/ipxe.efi bin/ipxe.lkrn
The file "myscript.ipxe" would appear as "autoexec.ipxe" on the USB
key, and would be loaded automatically on both BIOS and UEFI systems.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI device drivers will react to an asynchronous USB transfer
failure by dubiously terminating the scheduled transfer from within
the completion handler.
We already have code from commit fbb776f ("[efi] Leave USB endpoint
descriptors in existence until device is removed") that avoids freeing
memory in this situation, in order to avoid use-after-free bugs. This
is not sufficient to avoid potential problems, since with an xHCI
controller the act of closing the endpoint requires issuing a command
and awaiting completion via the event ring, which may in turn dispatch
further USB transfer completion events.
Avoid these problems by leaving the USB endpoint open (but with the
refill timer stopped) until the device is finally removed, as is
already done for control and bulk transfers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There may be multiple instances of EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL for
a single PCI segment. Use the bus number range descriptor from the
ACPI resource list to identify the correct protocol instance.
There is some discrepancy between the ACPI and UEFI specifications
regarding the interpretation of values within the ACPI resource list.
The ACPI specification defines the min/max field values to be within
the secondary (device-side) address space, and defines the offset
field value as "the offset that must be added to the address on the
secondary side to obtain the address on the primary side".
The UEFI specification states instead that the offset field value is
the "offset to apply to the starting address to convert it to a PCI
address", helpfully omitting to clarify whether "to apply" in this
context means "to add" or "to subtract". The implication of the
wording is also that the "starting address" is not already a "PCI
address" and must therefore be a host-side address rather than the
ACPI-defined device-side address.
Code comments in the EDK2 codebase seem to support the latter
(non-ACPI) interpretation of these ACPI structures. For example, in
the PciHostBridgeDxe driver there can be found the comment
Macros to translate device address to host address and vice versa.
According to UEFI 2.7, device address = host address + translation
offset.
along with a pair of macros TO_HOST_ADDRESS() and TO_DEVICE_ADDRESS()
which similarly negate the sense of the "translation offset" from the
definition found in the ACPI specification.
The existing logic in efipci_ioremap() (based on a presumed-working
externally contributed patch) applies the non-ACPI interpretation: it
assumes that min/max field values are host-side addresses and that the
offset field value is negated.
Match this existing logic by assuming that min/max field values are
host-side bus numbers. (The bus number offset value is therefore not
required and so can be ignored.)
As noted in commit 9b25f6e ("[efi] Fall back to assuming identity
mapping of MMIO address space"), some systems seem to fail to provide
MMIO address space descriptors. Assume that some systems may
similarly fail to provide bus number range descriptors, and fall back
in this situation to assuming that matching on segment number alone is
sufficient.
Testing any of this is unfortunately impossible without access to
esoteric hardware that actually uses non-zero translation offsets.
Originally-implemented-by: Thomas Walker <twalker@twosigma.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE seems to be almost alone in the UEFI world in attempting to shut
down cleanly, free resources, and leave hardware in a well-defined
reset state before handing over to the booted operating system.
The UEFI driver model does allow for graceful shutdown via
uninstallation of protocol interfaces. However, virtually no other
UEFI drivers do this, and the external code paths that react to
uninstallation are consequently poorly tested. This leads to a
proliferation of bugs found in UEFI implementations in the wild, as
described in commits such as 1295b4a ("[efi] Allow initialisation via
SNP interface even while claimed") or b6e2ea0 ("[efi] Veto the HP
XhciDxe Driver").
Try to avoid triggering such bugs by unconditionally skipping the
protocol interface uninstallation during UEFI boot services shutdown,
leaving the interfaces present but nullified and deliberately leaking
the containing memory.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The HP XhciDxe driver (observed on an HP EliteBook 840 G6) does not
respond correctly to driver disconnection, and will leave the PciIo
protocol instance opened with BY_DRIVER attributes even after
returning successfully from its Stop() method. This prevents iPXE
from subsequently connecting to the PCI device handle.
Veto this driver if the iPXE build includes a native xHCI driver.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI drivers (observed with the "Usb Xhci Driver" on an HP
EliteBook) are particularly badly behaved: they cannot be unloaded and
will leave handles opened with BY_DRIVER attributes even after
disconnecting the driver, thereby preventing a replacement iPXE driver
from opening the handle.
Allow such drivers to be vetoed by falling back to a brute-force
mechanism that will disconnect the driver from all handles, uninstall
the driver binding protocol (to prevent it from attaching to any new
handles), and finally close any stray handles that the vetoed driver
has left open.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Most veto checks are likely to use the manufacturer name and driver
name, so pass these as parameters to minimise code duplication.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow external code to dump the information for an opened protocol
information entry via DBG_EFI_OPENER() et al.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some devices (e.g. xHCI USB host controllers) may require the use of
large areas of host memory for private use by the device. These
allocations cannot be satisfied from iPXE's limited heap space, and so
are currently allocated using umalloc() which will allocate external
system memory (and alter the system memory map as needed).
Provide dma_umalloc() to provide such allocations as part of the DMA
API, since there is otherwise no way to guarantee that the allocated
regions are usable for coherent DMA.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The UEFI specification does not prohibit zero-length DMA mappings.
However, there is a reasonable chance that at least one implementation
will treat it as an invalid parameter. As a precaution, avoid calling
EFI_PCI_IO_PROTOCOL.Map() with a length of zero.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Include a potential DMA mapping within the definition of an I/O
buffer, and move all I/O buffer DMA mapping functions from dma.h to
iobuf.h. This avoids the need for drivers to maintain a separate list
of DMA mappings for each I/O buffer that they may handle.
Network device drivers typically do not keep track of transmit I/O
buffers, since the network device core already maintains a transmit
queue. Drivers will typically call netdev_tx_complete_next() to
complete a transmission without first obtaining the relevant I/O
buffer pointer (and will rely on the network device core automatically
cancelling any pending transmissions when the device is closed).
To allow this driver design approach to be retained, update the
netdev_tx_complete() family of functions to automatically perform the
DMA unmapping operation if required. For symmetry, also update the
netdev_rx() family of functions to behave the same way.
As a further convenience for drivers, allow the network device core to
automatically perform DMA mapping on the transmit datapath before
calling the driver's transmit() method. This avoids the need to
introduce a mapping error handling code path into the typically
error-free transmit methods.
With these changes, the modifications required to update a typical
network device driver to use the new DMA API are fairly minimal:
- Allocate and free descriptor rings and similar coherent structures
using dma_alloc()/dma_free() rather than malloc_phys()/free_phys()
- Allocate and free receive buffers using alloc_rx_iob()/free_rx_iob()
rather than alloc_iob()/free_iob()
- Calculate DMA addresses using dma() or iob_dma() rather than
virt_to_bus()
- Set a 64-bit DMA mask if needed using dma_set_mask_64bit() and
thereafter eliminate checks on DMA address ranges
- Either record the DMA device in netdev->dma, or call iob_map_tx() as
part of the transmit() method
- Ensure that debug messages use virt_to_phys() when displaying
"hardware" addresses
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Redefine the value stored within a DMA mapping to be the offset
between physical addresses and DMA addresses within the mapped region.
Provide a dma() wrapper function to calculate the DMA address for any
pointer within a mapped region, thereby simplifying the use cases when
a device needs to be given addresses other than the region start
address.
On a platform using the "flat" DMA implementation the DMA offset for
any mapped region is always zero, with the result that dma_map() can
be optimised away completely and dma() reduces to a straightforward
call to virt_to_phys().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE will currently fail all SNP interface methods with EFI_NOT_READY
while the network devices are claimed for use by iPXE's own network
stack.
As of commit c70b3e0 ("[efi] Always enable recursion when calling
ConnectController()"), this exposes latent UEFI firmware bugs on some
systems at the point of calling ExitBootServices().
With recursion enabled, the MnpDxe driver will immediately attempt to
consume the SNP protocol instance provided by iPXE. Since the network
devices are claimed by iPXE at this point, the calls by MnpDxe to
Start() and Initialize() will both fail with EFI_NOT_READY.
This unfortunately triggers a broken error-handling code path in the
Ip6Dxe driver. Specifically: Ip6DriverBindingStart() will call
Ip6CreateService(), which will call Ip6ServiceConfigMnp(), which will
return an error. The subsequent error handling code path in
Ip6CreateService() simply calls Ip6CleanService(). The code in
Ip6CleanService() will attempt to leave the all-nodes multicast group,
which will fail since the group was never joined. This will result in
Ip6CleanService() returning an error and omitting most of the required
clean-up operations. In particular, the MNP protocol instance will
remain opened with BY_DRIVER attributes even though the Ip6Dxe driver
start method has failed.
When ExitBootServices() is eventually called, iPXE will attempt to
uninstall the SNP protocol instance. This results in the UEFI core
calling Ip6DriverBindingStop(), which will fail since there is no
EFI_IP6_SERVICE_BINDING_PROTOCOL instance installed on the handle.
A failure during a call to UninstallMultipleProtocolInterfaces() will
result in the UEFI core attempting to reinstall any successfully
uninstalled protocols. This is an intrinsically unsafe operation, and
represents a fundamental design flaw in UEFI. Failure code paths
cannot be required to themselves handle failures, since there is no
well-defined correct outcome of such a situation.
With a current build of OVMF, this results in some unexpected debug
messages occurring at the time that the loaded operating system calls
ExitBootServices(). With the UEFI firmware in Hyper-V, the result is
an immediate reboot.
Work around these UEFI design and implementation flaws by allowing the
calls to our EFI_SIMPLE_NETWORK_PROTOCOL instance's Start() and
Initialize() methods to return success even when the network devices
are claimed for exclusive use by iPXE. This is sufficient to allow
MnpDxe to believe that it has successfully initialised the device, and
thereby avoids the problematic failure code paths in Ip6Dxe.
Debugged-by: Aaron Heusser <aaron_heusser@hotmail.com>
Debugged-by: Pico Mitchell <pico@randomapplications.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE will currently drop to TPL_APPLICATION whenever the current
system time is obtained via currticks(), since the system time
mechanism relies on a timer that can fire only when the TPL is below
TPL_CALLBACK.
This can cause unexpected behaviour if the system time is obtained in
the middle of an API call into iPXE by external code. For example,
MnpDxe sets up a 10ms periodic timer running at TPL_CALLBACK to poll
the underling EFI_SIMPLE_NETWORK_PROTOCOL device for received packets.
If the resulting poll within iPXE happens to hit a code path that
requires obtaining the current system time (e.g. due to reception of
an STP packet, which affects iPXE's blocked link timer), then iPXE
will end up temporarily dropping to TPL_APPLICATION. This can
potentially result in retriggering the MnpDxe periodic timer, causing
code to be unexpectedly re-entered.
Fix by recording the external TPL at any entry point into iPXE and
dropping only as far as this external TPL, rather than dropping
unconditionally to TPL_APPLICATION.
The side effect of this change is that iPXE's view of the current
system time will be frozen for the duration of any API calls made into
iPXE by external code at TPL_CALLBACK or above. Since any such
external code is already responsible for allowing execution at
TPL_APPLICATION to occur, then this should not cause a problem in
practice.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide opened EFI PCI devices with access to the underlying
EFI_PCI_IO_PROTOCOL instance, in order to facilitate the future use of
the DMA mapping methods within the fast data path.
Do not require the use of this stored EFI_PCI_IO_PROTOCOL instance for
memory-mapped I/O (since the entire point of memory-mapped I/O as a
concept is to avoid this kind of unnecessary complexity) or for
slow-path PCI configuration space accesses (since these may be
required for access to PCI bus:dev.fn addresses that do not correspond
to a device bound via our driver binding protocol instance).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI systems (observed with a Supermicro X11SPG-TF motherboard)
seem to fail to provide a valid ACPI address space descriptor for the
MMIO address space associated with a PCI root bridge.
If no valid descriptor can be found, fall back to assuming that the
MMIO address space is identity mapped, thereby matching the behaviour
prior to commit 27e886c ("[efi] Use address offset as reported by
EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL").
Debugged-by: Tore Anderson <tore@fud.no>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The UEFI specification allows uninstallation of a protocol interface
to fail. There is no sensible way for code to react to this, since
uninstallation is likely to be taking place on a code path that cannot
itself fail (e.g. a code path that is itself a failure path).
Where the protocol structure exists within a dynamically allocated
block of memory, this leads to possible use-after-free bugs. Work
around this unfortunate design choice by nullifying the protocol
(i.e. overwriting the method pointers with no-ops) and leaking the
memory containing the protocol structure.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the device path constructed via efi_describe() for the installed
EFI_BLOCK_IO_PROTOCOL device handle.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The UEFI specification provides a partial definition of an Infiniband
device path structure. Use this structure to construct what may be a
plausible path containing at least some of the information required to
identify an SRP target device.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The ACPI table contents are typically large and are likely to cause
any preceding error messages to scroll off-screen.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There is no standard defined for AoE device paths in the UEFI
specification, and it seems unlikely that any standard will be adopted
in future.
Choose to construct an AoE device path using a concatenation of the
network device path and a SATA device path, treating the AoE major and
minor numbers as the HBA port number and port multiplier port number
respectively.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Provide efi_netdev_path() as a standalone function, to allow for reuse
when constructing child device paths.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
When iPXE is downloading a file from an EFI_FILE_PROTOCOL instance
backed by an EFI_BLOCK_IO_PROTOCOL instance provided by the same iPXE
binary (e.g. via a hooked SAN device), then it is possible for step()
to be invoked as a result of the calls into the EFI_BLOCK_IO_PROTOCOL
methods. This can potentially result in efi_local_step() being run
prematurely, before the file has been opened and before the parent
interface has been attached.
Fix by deferring starting the download process until immediately prior
to returning from efi_local_open().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
iPXE will often have multiple drivers available for a USB device. For
example: some USB network devices will support both RNDIS and CDC-ECM,
and any device may be consumed by the fallback "usbio" driver under
UEFI in order to expose an EFI_USB_IO_PROTOCOL instance.
The driver scoring mechanism is used to select a device configuration
based on the availability of drivers for the interfaces exposed in
each configuration.
For the case of RNDIS versus CDC-ECM, this mechanism will always
produce the correct result since RNDIS and CDC-ECM will not exist
within the same configuration and so each configuration will receive a
score based on the relevant driver.
This guarantee does not hold for the "usbio" driver, which will match
against any device. It is a surprising coincidence that the "usbio"
driver seems to usually end up at the tail end of the USB drivers
list, thereby resulting in the expected behaviour.
Guarantee the expected behaviour by explicitly placing the "usbio"
driver at the end of the USB drivers list.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There appears to be no reason for avoiding recursion when calling
ConnectController(), and recursion provides the least surprising
behaviour.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The length as returned by UsbGetSupportedLanguages() should not
include the length of the descriptor header itself.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Allow temporary debugging code to call efi_wrap_systab() to obtain a
pointer to the wrapper EFI system table. This can then be used to
e.g. forcibly overwrite the boot services table pointer used by an
already loaded and running UEFI driver, in order to trace calls made
by that driver.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The call to UninstallMultipleProtocolInterfaces() will implicitly
disconnect any relevant controllers, and there is no specified
requirement to explicitly call DisconnectController() prior to
callling UninstallMultipleProtocolInterfaces().
However, some UEFI implementations (observed with the USB keyboard
driver on a Microsoft Surface Go) will fail to implicitly disconnect
the controller and will consequently fail to uninstall the protocols.
The net effect is that unplugging and replugging a USB keyboard may
leave the keyboard in a non-functional state.
Work around these broken UEFI implementations by including an
unnecessary call to DisconnectController() before the call to
UninstallMultipleProtocolInterfaces().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI USB drivers (e.g. the UsbKbDxe driver in EDK2) will react to
a reported EFI_USB_ERR_STALL by attempting to clear the endpoint halt.
This is redundant with iPXE's EFI_USB_IO_PROTOCOL implementation,
since endpoint stalls are cleared automatically by the USB core as
needed.
The UEFI USB driver's attempt to clear the endpoint halt can introduce
an unwanted 5 second delay per endpoint if the USB error was the
result of a device being physically removed, since the control
transfer will always time out.
Fix by reporting all USB errors as EFI_USB_ERR_SYSTEM instead of
EFI_USB_ERR_STALL.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some UEFI USB drivers (observed with the keyboard driver on a
Microsoft Surface Go) will react to an asynchronous USB transfer
failure by terminating the transfer from within the completion
handler. This closes the USB endpoint and, in the current
implementation, frees the containing structure.
This can lead to use-after-free bugs after the UEFI USB driver's
completion handler returns, since the calling code in iPXE expects
that a completion handler will not perform a control-flow action such
as terminating the transfer.
Fix by leaving the USB endpoint structure allocated until the device
is finally removed, as is already done (as an optimisation) for
control and bulk transfers.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Retrieve the address windows and translation offsets for the
appropriate PCI root bridge and use them to adjust the PCI BAR address
prior to calling ioremap().
Originally-implemented-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Define pci_ioremap() as a wrapper around ioremap() that could allow
for a non-zero address translation offset.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
