The bulk of the iPXE binary (the .textdata section) is physically
relocated at runtime to the top of the 32-bit address space in order
to allow space for an OS to be loaded. The relocation is achieved
with the assistance of segmentation: we adjust the code and data
segment bases so that the link-time addresses remain valid.
Segmentation is not available (for normal code and data segments) in
long mode. We choose to compile the C code with -mcmodel=kernel and
use a link-time address of 0xffffffffeb000000. This choice allows us
to identity-map the entirety of the 32-bit address space, and to alias
our chosen link-time address to the physical location of our .textdata
section. (This requires the .textdata section to always be aligned to
a page boundary.)
We simultaneously choose to set the 32-bit virtual address segment
bases such that the link-time addresses may simply be truncated to 32
bits in order to generate a valid 32-bit virtual address. This allows
symbols in .textdata to be trivially accessed by both 32-bit and
64-bit code.
There is no (sensible) way in 32-bit assembly code to generate the
required R_X86_64_32S relocation records for these truncated symbols.
However, subtracting the fixed constant 0xffffffff00000000 has the
same effect as truncation, and can be represented in a standard
R_X86_64_32 relocation record. We define the VIRTUAL() macro to
abstract away this truncation operation, and apply it to all
references by 32-bit (or 16-bit) assembly code to any symbols within
the .textdata section.
We define "virt_offset" for a 64-bit build as "the value to be added
to an address within .textdata in order to obtain its physical
address". With this definition, the low 32 bits of "virt_offset" can
be treated by 32-bit code as functionally equivalent to "virt_offset"
in a 32-bit build.
We define "text16" and "data16" for a 64-bit build as the physical
addresses of the .text16 and .data16 sections. Since a physical
address within the 32-bit address space may be used directly as a
64-bit virtual address (thanks to the identity map), this definition
provides the most natural access to variables in .text16 and .data16.
Note that this requires a minor adjustment in prot_to_real(), which
accesses .text16 using 32-bit virtual addresses.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[librm] Transition to protected mode within init_librm()
Long-mode operation will require page tables, which are too large to
sensibly fit in our .data16 segment in base memory.
Add a portion of init_librm() running in 32-bit protected mode to
provide access to high memory. Use this portion of init_librm() to
initialise the .textdata variables "virt_offset", "text16", and
"data16", eliminating the redundant (re)initialisation currently
performed on every mode transition as part of real_to_prot().
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Use the standard "pushl $function ; pushw %cs ; call prot_call"
sequence everywhere that prot_call() is used.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[bios] Make uses of REAL_CODE() and PHYS_CODE() 64-bit clean
On a 64-bit CPU, any modification of a register by 32-bit or 16-bit
code will destroy the invisible upper 32 bits of the corresponding
64-bit register. For example: a 32-bit "pushl %eax" followed by a
"popl %eax" will zero the upper half of %rax. This differs from the
treatment of upper halves of 32-bit registers by 16-bit code: a
"pushw %ax" followed by a "popw %ax" will leave the upper 16 bits of
%eax unmodified.
Inline assembly generated using REAL_CODE() or PHYS_CODE() will
therefore have to preserve the upper halves of all registers, to avoid
clobbering registers that gcc expects to be preserved.
Output operands from REAL_CODE() and PHYS_CODE() assembly may
therefore contain undefined values in the upper 32 bits.
Fix by using explicit variable widths (e.g. uint32_t) for
non-discarded output operands, to ensure that undefined values in the
upper 32 bits of 64-bit registers are ignored.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Move most arch/i386 files to arch/x86, and adjust the contents of the
Makefiles and the include/bits/*.h headers to reflect the new
locations.
This patch makes no substantive code changes, as can be seen using a
rename-aware diff (e.g. "git show -M5").
This patch does not make the pcbios platform functional for x86_64; it
merely allows it to compile without errors.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[prefix] Pad .text16 and .data16 segment sizes at build time
Commit c64747d ("[librm] Speed up real-to-protected mode transition
under KVM") rounded down the .text16 segment address calculated in
alloc_basemem() to a multiple of 64 bytes in order to speed up mode
transitions under KVM.
This creates a potential discrepancy between alloc_basemem() and
free_basemem(), meaning that free_basemem() may free less memory than
was allocated by alloc_basemem().
Fix by padding the calculated sizes of both .text16 and .data16 to a
multiple of 64 bytes at build time.
Debugged-by: Yossef Efraim <yossefe@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[iobuf] Improve robustness of I/O buffer allocation
Guard against various corner cases (such as zero-length buffers, zero
alignments, and integer overflow when rounding up allocation lengths
and alignments) and ensure that the struct io_buffer is correctly
aligned even when the caller requests a non-zero alignment for the I/O
buffer itself.
Add self-tests to verify that the resulting alignments and lengths are
correct for a range of allocations.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit f3fbb5f ("[malloc] Avoid integer overflow for excessively large
memory allocations") fixed signed integer overflow issues caused by
the use of ssize_t, but did not guard against unsigned integer
overflow.
Add explicit checks for unsigned integer overflow where needed. As a
side bonus, erroneous calls to malloc_dma() with an (illegal) size of
zero will now fail cleanly.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
ath_rx_init() demonstrates some serious confusion over how to use
pointers, resulting in (uint32_t*)NULL being used as a temporary
variable. This does not end well.
The broken code in question is performing manual alignment of I/O
buffers, which can now be achieved more simply using alloc_iob_raw().
Fix by removing ath_rxbuf_alloc() entirely.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The various early-exit paths in parse_uri() accidentally bypass the
URI field decoding. The result is that opaque or relative URIs do not
undergo URI field decoding, resulting in double-encoding when the URIs
are subsequently used. For example:
#!ipxe
set mac ${macstring}
imgfetch /boot/by-mac/${mac:uristring}
would result in an HTTP GET such as
GET /boot/by-mac/00%253A0c%253A29%253Ac5%253A39%253Aa1 HTTP/1.1
rather than the expected
GET /boot/by-mac/00%3A0c%3A29%3Ac5%3A39%3Aa1 HTTP/1.1
Fix by ensuring that URI decoding is always applied regardless of the
URI format.
Reported-by: Andrew Widdersheim <awiddersheim@inetu.net>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
TFTP URIs are intrinsically problematic, since:
- TFTP servers may use either normal slashes or backslashes as a
directory separator,
- TFTP servers allow filenames to be specified using relative paths
(with no initial directory separator),
- TFTP filenames present in a DHCP filename field may use special
characters such as "?" or "#" that prevent parsing as a generic URI.
As of commit 7667536 ("[uri] Refactor URI parsing and formatting"), we
have directly constructed TFTP URIs from DHCP next-server and filename
pairs, avoiding the generic URI parser. This eliminated the problems
related to special characters, but indirectly made it impossible to
parse a "tftp://..." URI string into a TFTP URI with a non-absolute
path.
Re-introduce the convention of requiring an extra slash in a
"tftp://..." URI string in order to specify a TFTP URI with an initial
slash in the filename. For example:
tftp://192.168.0.1/boot/pxelinux.0 => RRQ "boot/pxelinux.0"
tftp://192.168.0.1//boot/pxelinux.0 => RRQ "/boot/pxelinux.0"
This is ugly, but there seems to be no other sensible way to provide
the ability to specify all possible TFTP filenames.
A side-effect of this change is that format_uri() will no longer add a
spurious initial "/" when formatting a relative URI string. This
improves the console output when fetching an image specified via a
relative URI.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[ocsp] Avoid including a double path separator in request URI
The OCSP responder URI included within an X.509 certificate may or may
not include a trailing slash. We currently rely on the fact that
format_uri() incorrectly inserts an initial slash, which we include
unconditionally within the OCSP request URI.
Switch to using uri_encode() directly, and insert a slash only if the
X.509 certificate's OCSP responder URI does not already include a
trailing slash.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Commit 53d2d9e ("[uri] Generalise tftp_uri() to pxe_uri()") introduced
a regression in which an NFS root path would no longer be treated as
an unsupported root path, causing a boot with an NFS root path to fail
with a "Could not open SAN device" error.
Reported-by: David Evans <dave.evans55@googlemail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some protocols (such as ARP) may modify the received packet and re-use
the same I/O buffer for transmission of a reply. The SMSC95XX
transmit header is larger than the receive header: the re-used I/O
buffer therefore does not have sufficient headroom for the transmit
header, and the ARP reply will therefore fail to be transmitted. This
is essentially the same problem as in commit 2e72d10 ("[ncm] Reserve
headroom in received packets").
Fix by reserving sufficient space at the start of each received packet
to allow for the difference between the lengths of the transmit and
receive headers.
This problem is not caught by the current driver development test
suite (documented at http://ipxe.org/dev/driver), since even the large
file transfer tests tend to completely sufficiently quickly that there
is no need for the server to ever send an ARP request. The failure
shows up only when using a very slow protocol such as RFC7440-enhanced
TFTP (as used by Windows Deployment Services).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The LED pins are configured by default as GPIO inputs. While it is
conceivable that a board might actually use these pins as GPIOs, no
such board is known to exist.
The Linux smsc95xx driver configures these pins unconditionally as LED
outputs. Assume that it is safe to do likewise.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Expose the network interface name (e.g. "net0") as a setting. This
allows a script to obtain the name of the most recently opened network
interface via ${netX/ifname}.
Signed-off-by: Andrew Widdersheim <amwiddersheim@gmail.com>
Modified-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
[build] Add named configuration for public cloud environments
Add a named CONFIG=cloud configuration, which enables console types
useful for obtaining output from virtual machines in public clouds
such as AWS EC2.
An image suitable for use in AWS EC2 can be built using
make bin/ipxe.usb CONFIG=cloud EMBED=config/cloud/aws.ipxe
The embedded script will direct iPXE to download and execute the EC2
"user-data" file, which is always available to an EC2 VM via the URI
http://169.254.169.254/latest/user-data (regardless of the VPC
networking settings). The boot can therefore be controlled by
modifying the per-instance user data, without having to modify the
boot disk image.
Console output can be obtained via syslog (with a syslog server
configured in the user-data script), via the AWS "System Log" (after
the instance has been stopped), or as a last resort from the log
partition on the boot disk.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
The three nominally-disambiguated ENOTSUP errors accidentally all used
the same error disambiguator, rendering them identical. Fix by
changing all three values. We avoid reusing the 0x01 disambiguator
value, since that remains ambiguous in older binaries.
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Some BIOS console redirection capabilities do not work well with the
colourised debug messages used by iPXE. We already allow the range of
colours to be controlled via the DBGCOL=... build parameter. Extend
this syntax to allow DBGCOL=0 to be used to mean "disable colours".
Requested-by: Wissam Shoukair <wissams@mellanox.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown