zynq7000: SMP kernel

[jmaksymowicz]

Allows tasks to be scheduled on both CPU cores on zynq7000 platform.

Description

NOTE: the corresponding PR in PLO must be merged first - otherwise on zynq7000 kernel will hang waiting for other CPU cores which will never start.

Code is capable of detecting number of available CPUs at runtime, the NUM_CPUS constant is used as maximum number of CPUs to prepare for.

One change was made not related to SMP: size of page directories was changed from 0x4000 bytes to 0x2000 bytes, as the upper half was unnecessary

Memory attributes were changed in common armv7a code, which affects imx6ull (but should not cause significant change).

Using SMP on armv7a9-zynq7000-qemu causes drastic slowdown (about 4x-5x slower) when executing single-core workloads. This is because under QEMU the idle thread creates a lot of load on the host CPU, as well as contention on the timer spinlock. This slowdown does not occur on real hardware. For this reason I suggest limiting QEMU to emulating only one core, as we can test SMP configurations on real hardware.

Motivation and Context

Types of changes

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [ ] Chore (refactoring, style fixes, git/CI config, submodule management, no code logic changes)

How Has This Been Tested?

• [x] Already covered by automatic testing.
• [ ] New test added: (add PR link here).
• [x] Tested by hand on: armv7a9-zynq7000-zturn, armv7a9-zynq7000-qemu

Checklist:

• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [x] All new and existing linter checks and tests passed.
• [x] My changes generate no new compilation warnings for any of the targets.

Special treatment

• [x] This PR needs additional PRs to work: https://github.com/phoenix-rtos/plo/pull/329 https://github.com/phoenix-rtos/phoenix-rtos-devices/pull/504
• [ ] I will merge this PR by myself when appropriate.

[github-actions[bot]]

Unit Test Results

7 460 tests  +724   6 745 :white_check_mark: +695   39m 33s :stopwatch: + 6m 14s   420 suites ±  0     715 :zzz: + 75      1 files   ±  0       0 :x:  -  46 

Results for commit b1884db6. ± Comparison against base commit 47ac14ed.

This pull request removes 20 and adds 744 tests. Note that renamed tests count towards both.

``` phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit phoenix-rtos-tests/libc/exit ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/exit phoenix-rtos-tests/libc/math ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/math phoenix-rtos-tests/libc/misc ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/misc phoenix-rtos-tests/libc/pthread ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/pthread phoenix-rtos-tests/libc/scanf ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/scanf phoenix-rtos-tests/libc/stdio ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/stdio phoenix-rtos-tests/libc/stdlib ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/stdlib phoenix-rtos-tests/libc/string ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/string phoenix-rtos-tests/libc/time ‑ riscv64-generic-qemu:phoenix-rtos-tests/libc/time … ``` ``` phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_in phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_in_big phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_inout phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_inout_big phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_out phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.data_out_big phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.in_val phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.invalid_req phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.no_data phoenix-rtos-tests/ioctl/unit ‑ riscv64-generic-qemu:phoenix-rtos-tests/ioctl/unit.ioctl.not_valid_fd … ```

:recycle: This comment has been updated with latest results.

[jmaksymowicz]

Reverted change that activated L2 cache - it caused stability problems in some tests. I haven't found the reason for it yet. Because it's not necessary for SMP I think we should do it in a different PR.

EDIT: it didn't help, only reduced frequency of failing