aboutsummaryrefslogtreecommitdiffstats
path: root/src/arch/x86/include
Commit message (Collapse)AuthorAgeFilesLines
* [console] Support AltGr to access ASCII characters via remappingMichael Brown2022-02-151-0/+4
| | | | | | | | | | | | | Several keyboard layouts define ASCII characters as accessible only via the AltGr modifier. Add support for this modifier to ensure that all ASCII characters are accessible. Experiments suggest that the BIOS console is likely to fail to generate ASCII characters when the AltGr key is pressed. Work around this limitation by accepting LShift+RShift (which will definitely produce an ASCII character) as a synonym for AltGr. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [console] Centralise handling of key modifiersMichael Brown2022-02-151-0/+3
| | | | | | | Handle Ctrl and CapsLock key modifiers within key_remap(), to provide consistent behaviour across different console types. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [crypto] Add memory output constraints for big-integer inline assemblyMichael Brown2021-06-031-17/+37
| | | | | | | | | | | | | | | The ARM versions of the big-integer inline assembly functions include constraints to indicate that the output value is modified by the assembly code. These constraints are not present in the equivalent code for the x86 versions. As of GCC 11, this results in the compiler reporting that the output values may be uninitialized. Fix by including the relevant memory output constraints. Reported-by: Christian Hesse <mail@eworm.de> Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [cpio] Split out bzImage initrd CPIO header constructionMichael Brown2021-05-211-7/+0
| | | | | | | | | | | | iPXE will construct CPIO headers for images that have a non-empty command line, thereby allowing raw images (without CPIO headers) to be injected into a dynamically constructed initrd. This feature is currently implemented within the BIOS-only bzImage format support. Split out the CPIO header construction logic to allow for reuse in other contexts such as in a UEFI build. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [rng] Check for TSC support before using RTC entropy sourceMichael Brown2021-05-121-0/+3
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [pci] Avoid scanning nonexistent buses when using PCIAPI_DIRECTMichael Brown2021-04-101-2/+2
| | | | | | | | | | | | | | There is no method for obtaining the number of PCI buses when using PCIAPI_DIRECT, and we therefore currently scan all possible bus numbers. This can cause a several-second startup delay in some virtualised environments, since PCI configuration space access will necessarily require the involvement of the hypervisor. Ameliorate this situation by defaulting to scanning only a single bus, and expanding the number of PCI buses to accommodate any subordinate buses that are detected during enumeration. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [acpi] Allow for platforms that provide ACPI tables individuallyMichael Brown2021-03-011-0/+13
| | | | | | | | | | | | | | | | The ACPI API currently expects platforms to provide access to a single contiguous ACPI table. Some platforms (e.g. Linux userspace) do not provide a convenient way to obtain the entire ACPI table, but do provide access to individual tables. All iPXE consumers of the ACPI API require access only to individual tables. Redefine the internal API to make acpi_find() an API method, with all existing implementations delegating to the current RSDT-based implementation. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [linux] Use host glibc system call wrappersMichael Brown2021-02-281-6/+0
| | | | | | | | | | | | | | | | | | | | | | When building as a Linux userspace application, iPXE currently implements its own system calls to the host kernel rather than relying on the host's C library. The output binary is statically linked and has no external dependencies. This matches the general philosophy of other platforms on which iPXE runs, since there are no external libraries available on either BIOS or UEFI bare metal. However, it would be useful for the Linux userspace application to be able to link against host libraries such as libslirp. Modify the build process to perform a two-stage link: first picking out the requested objects in the usual way from blib.a but with relocations left present, then linking again with a helper object to create a standard hosted application. The helper object provides the standard main() entry point and wrappers for the Linux system calls required by the iPXE Linux drivers and interface code. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [bitops] Provide an explicit operand size for bit test instructionsMichael Brown2021-02-271-4/+4
| | | | | | | | | | | | | | | | | | Recent versions of the GNU assembler (observed with GNU as 2.35 on Fedora 33) will produce a warning message Warning: no instruction mnemonic suffix given and no register operands; using default for `bts' The operand size affects only the potential range for the bit number. Since we pass the bit number as an unsigned int, it is already constrained to 32 bits for both i386 and x86_64. Silence the assembler warning by specifying an explicit 32-bit operand size (and thereby matching the choice that the assembler would otherwise make automatically). Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Test for FXSAVE/FXRSTOR instruction supportMichael Brown2021-02-181-0/+3
| | | | | | | | | | | | | | | | | Assume that preservation of the %xmm registers is unnecessary during installation of iPXE into memory, since this is an operation that by its nature substantially disrupts large portions of the system anyway (such as the E820 memory map). This assumption allows us to utilise the existing CPUID code to check that FXSAVE/FXRSTOR are supported. Test for support during the call to init_librm and store the flag for use during subsequent calls to virt_call. Reduce the scope of TIVOLI_VMM_WORKAROUND to affecting only the call to check_fxsr(), to reduce #ifdef pollution in the remaining code. Debugged-by: Johannes Heimansberg <git@jhe.dedyn.io> Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [pci] Define pci_ioremap() for mapping PCI bus addressesMichael Brown2020-09-242-0/+26
| | | | | | | 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>
* [crypto] Avoid temporarily setting direction flag in bigint_is_geq()Michael Brown2020-07-071-17/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The UEFI specification states that the calling convention for IA-32 and x64 includes "Direction flag in EFLAGS is clear". This specification covers only the calling convention used at the point of calling functions annotated with EFIAPI. The specification explicitly states that other functions (such as private functions or static library calls) are not required to follow the UEFI calling conventions. The reference EDK2 implementation follows this specification. In particular, the EDK2 interrupt handlers will clear the direction flag before calling any EFIAPI functions, and will restore the direction flag when returning from the interrupt handler. Some EDK2 private library functions (most notably InternalMemCopyMem) may set the direction flag temporarily in order to make efficient use of CPU string operations. The current implementation of iPXE's bigint_is_geq() for i386 and x86_64 will similarly set the direction flag temporarily in order to make efficient use of CPU string operations. On some UEFI implementations (observed with a Getac RX10 tablet), a timer interrupt that happens to occur while the direction flag is set will reboot the machine. This very strongly indicates that the UEFI timer interrupt handler is failing to clear the direction flag before performing an affected operation (such as copying a block of memory). Work around such buggy UEFI implementations by rewriting bigint_is_geq() to avoid the use of string operations and so obviate the requirement to temporarily set the direction flag. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Ensure that inline code symbols are uniqueMichael Brown2018-03-211-1/+1
| | | | | | | | | | | | | | | Commit 6149e0a ("[librm] Provide symbols for inline code placed into other sections") may cause build failures due to duplicate label names if the compiler chooses to duplicate inline assembly code. Fix by using the "%=" special format string to include a guaranteed-unique number within the label name. The "%=" will be expanded only if constraints exist for the inline assembly. This fix therefore requires that all REAL_CODE() fragments use a (possibly empty) constraint list. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Provide symbols for inline code placed into other sectionsMichael Brown2018-03-211-0/+5
| | | | | | | | | | | | | Provide symbols constructed from the object name and line number for code fragments placed into alternative sections, such as inline REAL_CODE() assembly placed into .text16. This simplifies the debugging task of finding the source code corresponding to a given instruction pointer. Note that we cannot use __FUNCTION__ since it is not a preprocessor macro and so cannot be concatenated with string literals. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [rng] Use fixed-point calculations for min-entropy quantitiesMichael Brown2018-03-201-2/+2
| | | | | | | | | | | | | | We currently perform various min-entropy calculations using build-time floating-point arithmetic. No floating-point code ends up in the final binary, since the results are eventually converted to integers and asserted to be compile-time constants. Though this mechanism is undoubtedly cute, it inhibits us from using "-mno-sse" to prevent the use of SSE registers by the compiler. Fix by using fixed-point arithmetic instead. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [time] Add support for the ACPI power management timerMichael Brown2018-03-201-0/+1
| | | | | | | | Allow the ACPI power management timer to be used if enabled via TIMER_ACPI in config/timer.h. This provides an alternative timer on systems where the standard 8254 PIT is unavailable or unreliable. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Add facility to provide register and stack dump for CPU exceptionsMichael Brown2018-03-181-0/+44
| | | | | | | | | | | | | When DEBUG=librm_mgmt is enabled, intercept CPU exceptions and provide a register and stack dump, then drop to an emergency shell. Exiting from the shell will almost certainly not work, but this provides an opportunity to view the register and stack dump and carry out some basic debugging. Note that we can intercept only the first 8 CPU exceptions, since a PXE ROM is not permitted to rebase the PIC. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [cpuid] Allow input %ecx value to be specifiedMichael Brown2017-06-161-4/+5
| | | | | | | | | | | | | | | | | | | | For some CPUID leaves (e.g. %eax=0x00000004), the result depends on the input value of %ecx. Allow this subfunction number to be specified as a parameter to the cpuid() wrapper. The subfunction number is exposed via the ${cpuid/...} settings mechanism using the syntax ${cpuid/<subfunction>.0x40.<register>.<function>} e.g. ${cpuid/0.0x40.0.0x0000000b} ${cpuid/1.0x40.0.0x0000000b} to retrieve the CPU topology information. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [acpi] Make acpi_find_rsdt() a per-platform methodMichael Brown2017-05-232-0/+32
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [undi] Move PXE API caller back into UNDI driverMichael Brown2017-03-191-11/+0
| | | | | | | | | | | | | | As of commit 10d19bd ("[pxe] Always retrieve cached DHCPACK and apply to relevant network device"), the UNDI driver has been the only user of pxeparent_call(). Remove the unnecessary layer of abstraction by refactoring this code back into undinet.c, and fix the ability of undiisr.S to fall back to chaining to the original handler if we were unable to unhook our own ISR. This effectively reverts commit 337e1ed ("[pxe] Separate parent PXE API caller from UNDINET driver"). Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [time] Allow timer to be selected at runtimeMichael Brown2017-01-266-98/+9
| | | | | | | | | | | | | | | | | | | | | | Allow the active timer (providing udelay() and currticks()) to be selected at runtime based on probing during the INIT_EARLY stage of initialisation. TICKS_PER_SEC is now a fixed compile-time constant for all builds, and is independent of the underlying clock tick rate. We choose the value 1024 to allow multiplications and divisions on seconds to be converted to bit shifts. TICKS_PER_MS is defined as 1, allowing multiplications and divisions on milliseconds to be omitted entirely. The 2% inaccuracy in this definition is negligible when using the standard BIOS timer (running at around 18.2Hz). TIMER_RDTSC now checks for a constant TSC before claiming to be a usable timer. (This timer can be tested in KVM via the command-line option "-cpu host,+invtsc".) Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [cpuid] Provide cpuid_supported() to test for supported functionsMichael Brown2017-01-252-4/+5
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [pic8259] Fix definitions for "read IRR" and "read ISR" commandsMichael Brown2017-01-251-2/+2
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [undi] Clean up driver and device name informationMichael Brown2016-12-052-3/+2
| | | | | | | | | | | | | | | | | | | | Fix the <NULL> driver name reported by "ifstat" when using the undipci driver (due to the unnecessary extra device node inserted as a child of the PCI device). Remove the "UNDI-" prefix from device names since the driver name is also now visible via "ifstat", and tidy up the device name to match the format used by standard PCI devices. The output from "ifstat" now resembles: iPXE> ifstat net0: 52:54:00:12:34:56 using undipci on 0000:00:03.0 iPXE> ifstat net0: 52:54:00:12:34:56 using undionly on 0000:00:03.0 Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [acpi] Add support for ACPI power offMichael Brown2016-07-114-0/+30
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [rng] Check for functioning RTC interruptMichael Brown2016-07-101-0/+1
| | | | | | | | | | | | | | | | | | | | | On some platforms (observed in a small subset of Microsoft Azure (Hyper-V) virtual machines), the RTC appears to be incapable of generating an interrupt via the legacy PIC. The RTC status registers show that a periodic interrupt has been asserted, but the PIC IRR shows that IRQ8 remains inactive. On such systems, iPXE will currently freeze during the "iPXE initialising devices..." message. Work around this problem by checking that RTC interrupts are being raised before returning from rtc_entropy_enable(). If no interrupt is seen within 100ms, then we assume that the RTC interrupt mechanism is broken. In these circumstances, iPXE will continue to initialise but any subsequent attempt to generate entropy will fail. In particular, HTTPS connections will fail with an error indicating that no entropy is available. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [efi] Generalise EFI entropy generation to non-x86 CPUsMichael Brown2016-05-041-1/+0
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [tcpip] Do not fall back to using unoptimised TCP/IP checksummingMichael Brown2016-05-041-4/+2
| | | | | | | | Require architecture-specific code to make a deliberate choice to use the unoptimised generic_tcpip_continue_chksum() function, if there is no optimised version available. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [comboot] Support COMBOOT in 64-bit buildsMichael Brown2016-04-151-0/+130
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [int13] Allow default drive to be specified via "san-drive" settingMichael Brown2016-03-221-11/+0
| | | | | | | | | | | The DHCP option 175.189 has been defined (by us) since 2006 as containing the drive number to be used for a SAN boot, but has never been automatically used as such by iPXE. Use this option (if specified) to override the default SAN drive number. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [gdb] Add support for x86_64Michael Brown2016-03-221-0/+1
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [xen] Use generic test_and_clear_bit() functionMichael Brown2016-03-161-19/+0
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [bitops] Add generic atomic bit test, set, and clear functionsMichael Brown2016-03-161-0/+94
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Support ioremap() for addresses above 4GB in a 64-bit buildMichael Brown2016-02-263-0/+71
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [ioapi] Split ioremap() out to a separate IOMAP APIMichael Brown2016-02-262-16/+13
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Add support for running in 64-bit long modeMichael Brown2016-02-241-9/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for running the BIOS version of iPXE in 64-bit long mode. A 64-bit BIOS version of iPXE can be built using e.g. make bin-x86_64-pcbios/ipxe.usb make bin-x86_64-pcbios/8086100e.mrom The 64-bit BIOS version should appear to function identically to the normal 32-bit BIOS version. The physical memory layout is unaltered: iPXE is still relocated to the top of the available 32-bit address space. The code is linked to a virtual address of 0xffffffffeb000000 (in the negative 2GB as required by -mcmodel=kernel), with 4kB pages created to cover the whole of .textdata. 2MB pages are created to cover the whole of the 32-bit address space. The 32-bit portions of the code run with VIRTUAL_CS and VIRTUAL_DS configured such that truncating a 64-bit virtual address gives a 32-bit virtual address pointing to the same physical location. The stack pointer remains as a physical address when running in long mode (although the .stack section is accessible via the negative 2GB virtual address); this is done in order to simplify the handling of interrupts occurring while executing a portion of 32-bit code with flat physical addressing via PHYS_CODE(). Interrupts may be enabled in either 64-bit long mode, 32-bit protected mode with virtual addresses, 32-bit protected mode with physical addresses, or 16-bit real mode. Interrupts occurring in any mode other than real mode will be reflected down to real mode and handled by whichever ISR is hooked into the BIOS interrupt vector table. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Rename prot_call() to virt_call()Michael Brown2016-02-222-3/+3
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Support userptr_t in 64-bit buildsMichael Brown2016-02-211-1/+23
| | | | | | | | | | | | | | In a 64-bit build, the entirety of the 32-bit address space is identity-mapped and so any valid physical address may immediately be used as a virtual address. Conversely, a virtual address that is already within the 32-bit address space may immediately be used as a physical address. A valid virtual address that lies outside the 32-bit address space must be an address within .textdata, and so can be converted to a physical address by adding virt_offset. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Mark virt_offset, text16, data16, rm_cs, and rm_ds as constantMichael Brown2016-02-211-5/+5
| | | | | | | | The physical locations of .textdata, .text16 and .data16 are constant from the point of view of C code. Mark the relevant variables as constant to allow gcc to optimise out redundant reads. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Add phys_call() wrapper for calling code with physical addressingMichael Brown2016-02-201-3/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a phys_call() wrapper function (analogous to the existing real_call() wrapper function) for calling code with flat physical addressing, and use this wrapper within the PHYS_CODE() macro. Move the relevant functionality inside librm.S, where it more naturally belongs. The COMBOOT code currently uses explicit calls to _virt_to_phys and _phys_to_virt. These will need to be rewritten if our COMBOOT support is ever generalised to be able to run in a 64-bit build. Specifically: - com32_exec_loop() should be restructured to use PHYS_CODE() - com32_wrapper.S should be restructured to use an equivalent of prot_call(), passing parameters via a struct i386_all_regs - there appears to be no need for com32_wrapper.S to switch between external and internal stacks; this could be omitted to simplify the design. For now, librm.S continues to expose _virt_to_phys and _phys_to_virt for use by com32.c and com32_wrapper.S. Similarly, librm.S continues to expose _intr_to_virt for use by gdbidt.S. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Prepare for long-mode memory mapMichael Brown2016-02-191-3/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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()Michael Brown2016-02-191-4/+1
| | | | | | | | | | | | | 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>
* [librm] Provide an abstraction wrapper for prot_callMichael Brown2016-02-181-1/+22
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [librm] Discard argument as part of return from real_call()Michael Brown2016-02-161-1/+0
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [bios] Add bin-x86_64-pcbios build platformMichael Brown2016-02-1654-0/+5429
| | | | | | | | | | | | | | 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>
* [vmware] Expose GuestRPC mechanism in 64-bit buildsMichael Brown2016-01-052-0/+149
| | | | | | | | | The GuestRPC mechanism (used for VMWARE_SETTINGS and CONSOLE_VMWARE) does not use any real-mode code and so can be exposed in both 64-bit and 32-bit builds. Reported-by: Matthew Helton <mwhelton@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [xen] Wait for and clear XenStore event before receiving dataMichael Brown2015-06-301-0/+19
| | | | | | | | | | | | | | | Older, out-of-tree Xen kernel modules (such as those provided with SuSE Linux Enterprise Server 11) do not clear the leftover "event pending" bit when opening an event channel. Consequently, no event is ever delivered to indicate that there is information in the XenStore ring buffer, and the system hangs shortly after loading the xen-platform-pci kernel module. Work around this problem by always waiting for the XenStore event channel to be signalled, and clearing the event before processing the received data. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [serial] Add general abstraction of a 16550-compatible UARTMichael Brown2015-06-292-0/+42
| | | | Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [int13con] Add basic ability to log to a local disk via INT 13Michael Brown2015-05-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | Several popular public cloud providers do not provide any sensible mechanism for obtaining debug output from an OS which is failing to boot. For example, Amazon EC2 provides the "Get System Log" facility, which occasionally deigns to report a random subset of the characters emitted via the VM's serial port, but usually returns only a blank screen. (Amazingly, this is still superior to the debugging facilities provided by Azure.) Work around these shortcomings by adding a console type which sends output to a magically detected raw disk partition, and including such a partition within any iPXE .usb-format image. To use this facility: - build an iPXE .usb image with CONSOLE_INT13 enabled - boot the cloud VM from this image - after the boot fails, attach the VM's boot disk to a second VM - from this second VM, use "less -f -R /dev/sdb3" (or similar) to view the iPXE output. Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [efi] Add EFI entropy sourceMichael Brown2015-04-141-0/+1
| | | | | Originally-implemented-by: Jarrod Johnson <jbjohnso@us.ibm.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>
generated by cgit (git 2.34.1) at 2025-02-24 12:33:49 +0000