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* [linux] Use host glibc system call wrappersMichael Brown2021-03-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | 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>
* [time] Allow timer to be selected at runtimeMichael Brown2017-01-261-16/+10Star
| | | | | | | | | | | | | | | | | | | | | | 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>
* [linux] Avoid starting currticks() from zero every timeMichael Brown2014-03-071-1/+7
| | | | | | | | | | | | | | | | | | | iPXE uses currticks() (along with the MAC address(es) of any network devices) to seed the (non-cryptographic) random number generator. The current implementation of linux_currticks() ensures that the first call to currticks() will always return zero; this results in identical random number sequences on each run of iPXE on a given machine. This can cause odd-looking behaviour due to e.g. the reuse of local TCP port numbers. Fix by effectively rounding down the start time recorded by linux_currticks() to the nearest whole second; this makes it unlikely that consecutive runs of iPXE will use the exact same RNG sequence. (Note that none of this affects the cryptographic RNG, which uses /dev/random as a source of entropy.) Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [linux] Add missing #include <stddef.h>Marin Hannache2013-07-141-0/+1
| | | | | Signed-off-by: Marin Hannache <git@mareo.fr> Signed-off-by: Michael Brown <mcb30@ipxe.org>
* [linux] Add timerPiotr Jaroszyński2010-08-191-0/+80
Add linux timer API. Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com> Signed-off-by: Michael Brown <mcb30@ipxe.org>