lib/libc: Enable picolibc on qemu_x86_tiny #54186
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This was referenced Jan 28, 2023
Use the existing bits for newlib to make sure the picolibc files are also placed in pinned memory. Signed-off-by: Keith Packard <[email protected]>
When there's no malloc heap needed for picolibc, don't reserve the page frames that would be needed. This makes sure the kernel.demand_paging tests provoke the page faults as expected. Signed-off-by: Keith Packard <[email protected]>
Add another clause in the test_ram_perms code to verify that any pinned regions have the correct flags. Signed-off-by: Keith Packard <[email protected]>
These tests don't need any libc heap and currently fail when one is available. Signed-off-by: Keith Packard <[email protected]>
This test has trouble on qemu_x86_tiny and randomly generates a Double Fault error. I couldn't get it to reliably run with picolibc as a Double Fault usually occured before the test completed. I spent a couple of hours attempting to track this down and found that it happens when code pages for the main thread get unmapped because the qemu_x86_tiny intentionally offers very few available PTEs. Work around this by just using the minimal libc for this test. Signed-off-by: Keith Packard <[email protected]>
With all of the test suite issues on this board fixed, qemu_x86_tiny should now be usable with picolibc. Signed-off-by: Keith Packard <[email protected]>
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dcpleung
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This series resolves the small number of failures when running the test suite using picolibc by default. All of them are pretty straightforward except for the change to the
kernel.memory_protectiontest -- that test generates double fault errors on this board during nearly every run, even with the minimal C library, although in that case the error usually occurs after the test completes, during the cleanup code. I spent some quality time digging into it and it looks like whatever memory protection changes are made cause troubles when faulting in text pages for the main thread. I'm afraid I gave up attempting to find the actual problem and just switched to forcing that test to use the minimal C library.Fixes #54148