Genode code already expects MMU to be disabled when starting the
kernel. It is enabled eventually in Bootstrap::Platform::enable_mmu,
after setting up translation tables. Unfortunately nothing ensures
this is actually the case. If MMU happens to be enabled when entering
the kernel things go downhill pretty fast after we start messing with
TTBR.
This patch ensures MMU is disabled for EL1, EL2, EL3 dependent on the
exception level of the CPU core, which is entering the kernel.
This should allow base-hw to start correctly on Quartz64 A board.
The `lookup_translation` function got introduced and is used only in the
context to proof whether a cache maintainance function can be executed
safely by the kernel. Unfortunately, it did not checked write permissions,
which can lead to permission faults. This commit restricts the lookup
function to only succeed when the target page is writeable. Consequently,
the lookup function gets renamed to `lookup_rw_translation`.
Fixgenodelabs/genode#4348
According to ARM Cortex-A55 Core Technical Reference Manual r1p0 the
lowest 8 bits (Aff0) of MPIDR register represent thread IDs within a
multi-threaded core. The actual core identification bits are in Aff1.
This layout can be identified by checking the MT bit of MPIDR register.
Basically, if MT=1 core id is in Aff1, if MT=0 core id is in Aff0.
Without this change Genode will identify all CPU cores on A55 as primary
(0) core.
Its worth to mention that Cortex-A55 by itself is not a multi-threaded
CPU. Aff0 values are always expected to be 0 for pure A55 cores. A55
cores can however be paired with cores that are multi-threaded. To
support such big.LITTLE CPUs in Genode we'd probably need to add a
different mechanism for mapping MPIDR values to logical, contignous
core IDs which Genode expects.
Ref:
https://developer.arm.com/documentation/100442/0100/register-descriptions/aarch64-system-registers/mpidr-el1--multiprocessor-affinity-register--el1?lang=en
The soft ABI implies purely software floating point implementation.
This is not the case for Genode however. For example core's
exception_vector.S uses vmsr instruction. This builds fine with with
GCC based toolchain, but clang with integrated-as complains:
src/core/spec/arm/exception_vector.S:122:2: error: instruction requires: VFP2
vmsr fpexc, r1
^
Fix this by passing softfp to mfloat-abi command on ARMv7. This allows
usage of FP HW, but implies soft-floating point ABI.
Issue #4421
According to C++11 reference:
"If the strictest (largest) alignas on a declaration is weaker than
the alignment it would have without any alignas specifiers (that is,
weaker than its natural alignment or weaker than alignas on another
declaration of the same object or type), the program is ill-formed:"
https://en.cppreference.com/w/cpp/language/alignas
The code requests 4 byte alignment for Genode::Arm_cpu::Context.
The Context structure inherits Genode::Arm_cpu::Fpu_context which
has minimum alignment requirement of 8 bytes, due to uint64_t d0_d31
member. This makes the 4 byte value in Context's alignas specifier
invalid (smaller than allowed minimum).
Similar situation takes place in Arm_64 case. The claimed minimum
alignment of Context is 8 bytes, but the fpu_state member imposes 16
bytes alignment (explicitly specified in Fpu_state declaration).
In both cases the code builds fine with GCC 8.3.0, but fails with
clang which claims that "requested alignment is less than minimum
alignment of X for type", where X is 8 on ARM and 16 on AArch64.
Ref: https://eel.is/c++draft/dcl.align#5
Issue #4421
Even though the use of the C++ exception mechanism (and the implicit use
of the cxx heap) is not a problem at the server side, this patch
nevertheless replaces the exception-based return-value handling to make
the code consistent with the ipc_call path.
Issue #3612
On some boards or emulators a CPU might be executing in hyp mode
when entering Genode's bootstrap code. In that mode the 'cps' instruction
is not defined. Therefore, we change the way the boot cpu is identified.
Ref #3415
* renamed rpi pic to Bcm2835_pic
* renamed rpi3 pic to Bcm2837_pic
* added bcm2837 control for setting prescaler value (to fix timer_accuracy)
* changed handling of all interrupts for rpi3 by cascading to bcm2835 pic
* rpi3 irq controller base address made consistent with rpi
* added usb controller memory region for pic on rpi3 (for SOF interrupts)
Ref #3415
This patch improves the robustness of the CPU-affinity handling.
- The types in base/affinity.h received the accessors
'Location::within(space)' and 'Affinity::valid', which alleviates
the fiddling with coordinates when sanity checking the values,
in init or core.
- The 'Affinity::Location::valid' method got removed because its
meaning was too vague. For sanity checks of affinity configurations,
the new 'within' method is approriate. In cases where only the x,y
values are used for selecting a physical CPU (during thread creation),
the validity check (width*height > 0) was not meaningful anyway.
- The 'Affinity::Location::from_xml' requires a 'Affinity::Space'
as argument because a location always relates to the bounds of
a specific space. This function now implements the selection of
whole rows or columns, which has previously a feature of the
sandbox library only.
- Whenever the sandbox library (init) encounters an invalid affinity
configuration, it prints a warning message as a diagnostic aid.
- A new 'Affinity::unrestricted' function constructs an affinity that
covers the whole affinity space. The named functions clarifies
the meaning over the previous use of the default constructor.
- Core's CPU service denies session requests with an invalid
affinity parameter. Previously, it would fall back to an
unrestricted affinity.
Issue #4300
This patch changes the 'Allocator' interface to the use of 'Attempt'
return values instead of using exceptions for propagating errors.
To largely uphold compatibility with components using the original
exception-based interface - in particluar use cases where an 'Allocator'
is passed to the 'new' operator - the traditional 'alloc' is still
supported. But it existes merely as a wrapper around the new
'try_alloc'.
Issue #4324
The includes for the address-space-ID allocator and the translation table are
usually specific to the CPU in use. Therefore these includes can be moved from
their current location in the board header to the CPU headers. This reduces the
number of decisions a board maintainer has to make if the CPU model he's aiming
for is already available.
This can probably also be applied for other includes in the board headers but I
intentionally leave it for a future commit as I don't have the time to do it
all now.
Ref #4217
For base-hw Core, we used to add quite some hardware-specific include paths
to 'INC_DIR'. Generic code used to include, for instance, '<cpu.h>' and
'<translation_table.h>' using these implicit path resolutions. This commit
removes hardware-specific include paths except for
1) the '<board.h>' include paths (e.g., 'src/core/board/pbxa9'),
2) most architecture-specific include paths (e.g., 'src/core/spec/arm_v7'),
3) include paths that reflect usage of virtualization or ARM Trustzone
(e.g., 'src/core/spec/arm/virtualization').
The first category is kept because, in contrast to the former "spec"-mechanism,
the board variable used for this type of resolution is not deprecated and the
board headers are meant to be the front end of hardware-specific headers
towards generic code which is why they must be available generically via
'<board.h>'.
The second category is kept because it was suggested by other maintainers that
simple arch-dependent headers (like for the declaration of a CPU state) should
not imply the inclusion of the whole '<board.h>' and because the architecture
is given also without the former "spec"-mechanism through the type of the build
directory. I think this is questionable but am fine with it.
The third category is kept because the whole way of saying whether
virtualization resp. ARM Trustzone is used is done in an out-dated manner and
changing it now would blow up this commit a lot and exceed the time that I'm
willing to spend. This category should be subject to a future issue.
Ref #4217
The 'src/core/board/<board>/board.h' header is thought as front end of
hardware-specific headers of a given board towards the generic base-hw Core
code. Therefore it leads to problems (circular includes) if the board.h header
is included from within another hardware-specific header.
If hardware-specific headers access declarations from namespace Board in a
definition, the definition should be moved to a compilation unit that may
include board.h. If hardware-specific headers access declarations from board.h
in a declaration, they should either use the primary declaration from the
original header or, if the declaration must be selected according to the board,
another board-specific header should be introduced to reflect this abstraction.
This is applied by this commit for the current state of base-hw.
Ref #4217
It is not necessary to have a class, an object, and a generic header for the
perfomance counter. The kernel merely enables the counter using cpu registers
('msr' instructions, no MMIO) on arm_v6 and arm_v7 only. Therefore this commit
makes the header arm-specific and replaces class and global static object with
a function for enabling the counter.
Fixes#4217
Let the kernel's driver for the global IRQ controller be a member of the one
Kernel::Main object instead of having it as static variables in the drivers for
the local IRQ controllers. Note that this commit spares out renaming 'Pic' to
'Local_interrupt_controller' which would be more sensible now with the new
'Global_interrupt_controller' class. Furthermore, on ARM boards the commit
doesn't move 'Distributer' stuff to the new global IRQ controller class as they
don't have real data members (only MMIO) and can be instanciated for each CPU
anew. However, the right way would be to instanciate them only once in Main as
well.
Ref #4217
The unmanaged-singleton approach was used in this context only because of the
alignment requirement of the Core main-UTCB. This, however can also be achieved
with the new 'Aligned' utility, allowing the UTCB to be a member of the Core
main-thread object.
Ref #4217
It's sufficient to access the boot info only on kernel initialization time.
Therfore, it can remain completely hidden to the rest of the kernel inside
kernel/main.cc in the initialization function.
Ref #4217
This commit introduces the Kernel::Main class that replaces the former way of
initializing the kernel (former 'kernel_init' function) and calling the C++
kernel entry handler (former 'kernel' function). These two are now
'Main::initialize_and_handle_kernel_entry' and 'Main::handle_kernel_entry'.
Also reading the execution time of the idle threads was already moved to
'Main'. The one static Main instance is meant to successivly replace all the
global static objects of the base-hw kernel with data members of the Main
instance making the data model of the kernel much more comprehensible. The
instance and most of its interface are hidden in kernel/main.cc. There are only
rare cases where parts of the Main interface must be accessible from the
outside. This should be done in the most specific way possible (see main.h)
and, if possible, without handing out references to Main data members or the
Main instance itself.
Ref #4217
