65 lines
3.3 KiB
Plaintext
65 lines
3.3 KiB
Plaintext
* Fix pre-ARMv7 support
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Currently the cross-tools are compiled to default to ARMv7, Cortex-A8, and
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hardware floating point. This works around the missing atomic support, see
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below. This should be done by setting the -mcpu,-march and -mfloat-abi
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switches at build time, however, they aren't passed on to haikuporter
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during the bootstrap build, leading to the ports failing to find the
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gcc atomic ops again.
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* Determine how to handle atomic functions on ARM.
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GCC inlines are not supported, since the instructionset is ill-equiped for
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this on older (pre-ARMv7) architectures. We possibly have to do something
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similar to the linux kernel helper functions for this....
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On ARMv7 and later, this is not an issue. Not sure about ARMv6, we may get
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it going there. ARMv5 definitely needs us to write some code, but is it
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worth the trouble?
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* Fix multilib support
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ARM-targetting versions of gcc are usually built with multilib support, to
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allow targetting architectures with or without FPU, and using either ARM
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or Thumb instructions. This bascally means a different libgcc and libstdc++
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are built for each combination.
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The cross-tools can be built with multilib support. However, we do some
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tricks to get a separate libgcc and libstdc++ for the kernel (without C++11
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threads support, as that would not build in the kernel). Building this lib
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is not done in a multilib-aware way, so you get one only for the default
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arch/cpu/abi the compiler is targetting. This is good enough, as long as that
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arch is the one we want to use for the kernel...
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Later on, the bootstrap build of the native gcc compiler will fail, because
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it tries to build its multilib library set by linking against the different
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versions of libroot (with and without fpu, etc). We only build one libroot,
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so this also fails.
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* Figure out how to get page flags (modified/accessed) and implement it ;)
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use unmapped/read-only mappings to trigger soft faults
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for tracking used/modified flags for ARMv5 and ARMv6
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* Fix serial port mapping. Currently kernel uses the haiku_loader identity
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mapping for it, but this lives in user virtual address space...
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(Need to not use identity mapping in haiku_loader but just
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map_physical_memory() there too so it can be handed over without issues).
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* Seperate ARM architecture/System-On-Chip IP code. Needed very early on
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(Interrupt Controller, Timer IP block). Should use FDT for this too.
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* Use FDT to remove all the seperate board definitions in the build. Use a
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"minimal ARM architecture version" as the compile flag for ARM support.
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This to be able to optimize a kernel build for a specific SoC (or family).
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* KDL disasm module.
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cf.
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http://fxr.watson.org/fxr/source/arch/arm/arm/disassem.c?v=NETBSD
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* Add KDL hangman to the boot floppy image for more enjoyment during porting....
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* Userland...........
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* Bootloader TODOs:
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- Better handling of memory ranges. Currently no checks are done, and
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memory is assumed to be a single contiguous range, and the "input"
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ranges for mmu_init are setup, but never considered.
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- Allocate the pagetable range using mmu_allocate() instead of identity
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mapping it. That way, there's a bit more flexibility in where to place
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it both physically and virtually. This will need a minor change on the
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kernel side too (in the early pagetable allocator).
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