ACTIVE - Kernel with migrating threads as IPC https://metanimi.dy.fi/cgit/kmi/atom?h=master 2024-10-30T00:32:02Z 2024-10-30T00:32:02Z Kimplul kimi.h.kuparinen@gmail.com 2024-10-30T00:32:02Z urn:sha1:7a23d95b6e432170d6575f515616e5936d53c85e 2024-10-30T00:18:12Z Kimplul kimi.h.kuparinen@gmail.com 2024-10-30T00:18:12Z urn:sha1:e7b5881903ad81efee63966e7d2c42524d465dfc 2024-10-29T19:17:31Z Kimplul kimi.h.kuparinen@gmail.com 2024-10-29T19:17:31Z urn:sha1:5976ad390a15726c3ddfacf8c8b282c8350f9554 2024-07-09T14:35:56Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-09T14:35:56Z urn:sha1:298636079d912d0936f8156a609fe74b839c547b + User has to 'free' the 0 page before it becomes accessible to mapping. Probably worth noting that this is likely VERY niche and mainly concerns stuff like certain kinds of emulators that I'm still eons from implementing, but still. Unbacked pages can also be useful for some kinds of notifications, like 'if someone writes to this page, please report it to me with this ID' or whatever, I remember seeing some discussion about it somewhere but that's also not really relevant for the moment. Most significantly, at least with the current design, after the null page is freed it becomes available for use to regular req_mem() calls, so users should probably using locks around memory requests. That's probably a good idea anyway as internally the kernal has to lock the virtual memory, and without a scheduler it might cause threads to spin for a while in the kernel which is rather bad. 2024-07-08T15:04:03Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-08T14:43:59Z urn:sha1:e134202611a50b358c147c92bfb8a7f443030b8b + Anything extern is right out as LLVM doesn't produce correct code for them. Maybe if I added some extra attributes but I'm skeptical. Replaced with static variables and getters/setters. + Inline ASM is apparently a bit buggy, so use an assembly stub when jumping to init. + Minimize work done in main() to minimize chance of LLVM doing something silly. Still not 100% certain that I shouldn't just write the main() as an assembly stub in arch/riscv64 to be absolutely sure everything works as intended. + Make .kernel.start section SHF_ALLOC, otherwise lld complains about pc-relative addressing Probably some other stuff as well that I'm forgetting right now. But at least with LLVM14 LTO seems to work, which is pretty cool? 2024-07-07T04:00:43Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-07T04:00:43Z urn:sha1:122374c362ba8bb9082385da3c82e264ab594f15 + Had some minor issues with a wraparound of size_t that effectively meant that some regions were allocated twice. Also, booting should be a bit more reliable now, turned out that the previous iteration of the booting was just accidentally working due to the kernel being placed 'close enough' in RAM to where it was linked to. Fixed by allocating a vmem of O1 that maps the kernel to a 2MiB boundary at boot, pretty nifty. 2024-07-06T16:31:13Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-06T16:31:13Z urn:sha1:f810f1583725b84d3538adfe2aab6dea00f5ae87 2024-07-06T15:14:04Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-06T15:14:04Z urn:sha1:76517486919657ecadda9867125dc6730f29a5b7 + The system is now a bit simpler and hopefully easier to understand, while also extending the shared memory to be 1:N, where there is one owner who may become a zombie while waiting for the N to die. 2024-07-05T17:14:46Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-05T17:14:46Z urn:sha1:83a6fc687cab3ee87c6cae1324728521f9877ad0 2024-07-05T16:38:11Z Kimplul kimi.h.kuparinen@gmail.com 2024-07-05T16:38:11Z urn:sha1:e09edb5d54e39bd9509a1dc450df5ab320759f97 + Took some fairly significant changes, for one the kernel is no longer relocated at the start of a boot, instead it sits wherever the user decides the kernel should sit. Similarly, the initial kernel stack and page table are stored within the binary, slightly bloating the size but making it much safer to boot since there's really no chance of us overwriting the fdt or initrd in memory.