openarch 0.9.0、两个板级包的 run 档 - #342
Merged
Merged
Conversation
`mcpplibs.openarch@0.9.0` adds an ARMv7-A backend, and with it the answer to a question the layer's three original machines could not ask. All of them are 64-bit with 64-bit page-table entries, and `pte_encode.h` recorded that as a fact about every machine there. ARMv7-A's short-descriptor entry is 32 bits. The value fits in the `arch_u64` the interface carries, so the carrier did not change; what was missing is a way to ASK for the storage width. A kernel sizing a table from `sizeof(arch::pte)` builds one twice as large as the hardware walks, and nothing diagnoses it — the table is well formed, the entries are correct, and the machine reads the gaps. `arch_pte_entry_bytes()` is the answer and every backend implements it. Cortex-M could not settle this: it is a 32-bit machine with an MPU and no page table, so its pte group exists and refuses. A 32-bit machine WITHOUT paging leaves the question where it was. `openarch:preemption` is withheld on armv7a, by the mechanism Cortex-M already uses to withhold `openarch:address-space`: the resumption address lives on the SVC stack rather than in a register, so a trap-time switch is well defined only if the resumed context was suspended the same way, and that is not a design this backend has measured. `mcpplibs.riscv-virt-rt@0.7.1` and `mcpplibs.aarch64-virt-rt@0.2.1` move their emulator onto the `run` tier. The untiered form meant `Always`, so a CI job that compiled firmware and never ran it downloaded 33-36 MB of emulator for nothing. The engine has had `when` since 2026.9.4.2 and `cortex-m-rt` adopted it; these two had not, which left one batch with two spellings. Audited before submission: 37 versions, 74 URLs fetched and hashed against the index, every tarball's own manifest checked for identity, version and escaping path dependencies.
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
openarch 0.9.0 加了 ARMv7-A 后端,以及它回答的那个宽度问题:原来三台机器都是 64 位、条目也是 64 位,
pte_encode.h把这条当成事实写着;ARMv7-A 短描述符是 32 位。值放得下,存储放不下——用sizeof(arch::pte)定尺寸的页表会大一倍,而没有任何东西会诊断它。新增arch_pte_entry_bytes(),五个后端各自实现。Cortex-M settle 不了这个问题:32 位但没有页表,pte 组是「存在并拒绝」。
openarch:preemption在 armv7a 上被扣住,用的是 Cortex-M 扣住openarch:address-space的同一机制。两个板级包把模拟器移到
run档:无档等于Always,只编译不运行的 CI 也会下 33–36 MB。引擎从 2026.9.4.2 起就有when,cortex-m-rt 迁了、这两个没有。审计:37 个版本、74 个 URL 全下载核 sha256,并核对每个 tarball 内 manifest 的身份、版本与逃逸 path。