The frame-pointer-based backtrace does not work without enabling
-fno-omit-frame-pointer explicitly and in most cases leads to page
faults because non-pointer stack values are dereferenced during the
walk. The best we can do is to limit the backtrace walk to the stack of
the current thread to prevent page faults unrelated to the system state
without the use of the backtrace utility.
This commit introduces a printable Backtrace class usable in
Genode::log(), Genode::trace(), etc. The class is based on the new
function for_each_return_address(auto const &fn) that walks the stack in
its limits and calls fn() for each discovered return address on the
stack in the new os/include/os/backtrace.h. Archtecture-specific
stack-pointer retrieval and walk loops are implemented in dedicated
os/include/spec/<arch>/os/for_each_return_address.h files. Also, the
well-known Genode::backtrace() function (which logs the return-address
values) is provided for backwards compatibility.
Fixes#5078
This API rework eases the access to memory-mapped I/O registers and
interrupts when using the platform driver. It introduces the notions of
- Platform::Device - one device obtained from a platform session
- Platform::Device::Mmio - locally-mapped MMIO registers of a device
- Platform::Device::Irq - interface for receiving device interrupts
The patch touches several drivers. Some drivers would require a
significant structural change to adopt the new API (e.g., net/virtio,
dde_linux drivers, imx gpio). In these cases, the patch adds
compatibility shims meant to be temporary. In other cases (e.g., imx
i2c), the adaptation was simple enough to carry through.
Fixes#4075
