[rng] Use fixed-point calculations for min-entropy quantities
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>
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>
Rewrite (and relicense) the header files which are included in all
builds of iPXE (including non-Linux builds).
Signed-off-by: Michael Brown <mcb30@ipxe.org>
There exists an smbios userspace library so implementing this is
probably possible, but doesn't seem really important to have in
userspace. Hence provide a dummy implementation returning an error.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Add user access API for linux.
On linux userspace virtual == user == phys addresses. Physical
addresses also being the same is wrong, but there is no general way of
converting userspace addresses to physical as what appears to be
contiguous in userspace is physically fragmented. Currently only the
DMA memory is special-cased, but its conversion to bus addresses is
done in phys_to_bus. This is known to break virtio as it is passing
phys addresses to the virtual device.
Signed-off-by: Piotr Jaroszyński <p.jaroszynski@gmail.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Michael Brown