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97b25da8b1
`align_memory()` in hardware.py both modifies the first normal memory
region to adjust the base of it for alignment, and adds an extra
reserved region to our list of reserved regions. This then feeds
through `get_addrspace_exclude` which inverts the regions given
and turns it into the available "device memory" at user-level.
dev_mem = hardware.utils.memory.get_addrspace_exclude(
list(reserved) + phys_mem + kernel_devs, config)
Anything as an argument to this is not given as "device memory" by
the kernel. (It does not precisely match how the kernel works).
However, since `align_memory()` has adjusted both the phys_mem up
(which *would* have added this region as "device" memory) but also
added it to "reserved" region, which then made it disappear entirely,
as "reserved" regions are not exposed to userspace.
However, this **does not** match the behaviour of the kernel, as it was
not reserved, so this behaviour did not match the untypeds given to
userspace. This commit solves this by removing the extra reserved
region being added for that memory.
PR #1426 worked around this issue by removing the alignment on AArch64.
Whilst this fixed the issue that microkit was seeing, it just masked
the underlying issue. Reverting that PR, then applying this fix,
results in the following platform_gen.yaml:
devices:
- end: 0x1000000
start: 0x0
- end: 0xff800000
start: 0x3b400000
- end: 0xff841000
start: 0xff801000
- end: 0x100000000000
start: 0xff843000
memory:
- end: 0x3b400000
start: 0x1000000
Note especially the device region from 0x0 to 0x1000000; which is the
combination of the 0x0 to 0x1000 reserved region, and the 0x1000 to
0x1000000 reserved by the kernel's alignment requirement. Previously,
the platform_gen.yaml reported only the 0x0 to 0x1000 region,
devices:
- end: 0x1000
start: 0x0
- end: 0xff800000
start: 0x3b400000
- end: 0xff841000
start: 0xff801000
- end: 0x100000000000
start: 0xff843000
memory:
- end: 0x3b400000
start: 0x1000000
I will be following this commit up with a PR to instead make the
alignment-reserved region into a new memory region, since there's not
any reason why userspace can't use this memory.
This has been tested on a few platforms with sel4test and with
microkit on the pi4B.
Signed-off-by: julia <git.ts@trainwit.ch>