The 'base-linux' API is used by hybrid Genode/Linux programs for the
lx_hybrid library. This API archive happend to contain other libraries -
like seccomp - that are solely needed for building core. With the change
of the build system in issue #4599, the build system would attempt to
build all libraries instead of merely the library dependencies of the
available targets. Hence, it would trigger the build of, e.g., the
seccomp library for each user of the base-linux API.
This patch avoids these superfluous build steps by pruning the content
of lib/mk/ to the libraries actually needed for lx_hybrid users.
Issue #4599
The kernel-agnostic 'Trace::timestamp' function for arm_64 executes the
'mrs %0, pmccntr_el0' instruction, which is not permitted for user-level
programs on Linux. This patch shadows the generic timestamp.h header
with dummy that returns zero. This return value prompts the timeout
framework to disable the interpolation of time based on timestamps. This
avoid the illegal-instruction abort but comes with two llimitations:
First, time measurements are effectlively limited to a granulariry of 1
millisecond (deliberately constrained by the timer driver).
The quirk is applied when using the base-linux API. Should a generic
application (that uses the base API only) call 'Trace::timestamp'
directly, the illegal instruction is executed.
Issue #4136
This patch adds support for running Genode/Linux on the AARCH64
architecture.
- The kernel-agnostic startup code (crt0) had to be extended to
capture the initial stack pointer, which the Linux kernel uses
to pass the process environment. This is in line with the
existing startup code for x86_32 and x86_64.
- The link order of the host libraries linked to lx_hybrid
programs had to be adjusted such that libgcc appears at last
because the other libraries depend on symbols provided by
libgcc.
- When using AARCH64 Linux as host, one can execute run scripts
via 'make run/<script> KERNEL=linux BOARD=linux' now.
Issue #4136
By moving core's build-description to a library - a pattern already
employed for the other base platforms - we become able to cleanly split
x86-specific code (I/O-port access) from generic code. This is a
prerequisite for enabling non-x86 architectures such as AARCH64.
Issue #4136
