Files
servo/python
Jonathan Schwender 889ffc9880 ohos: Fix JIT detection (#40130)
On recent versions of HarmonyOS the previous JIT detection does not
appear to work anymore, since the second `mmap` succeeds. This moves the
failure in spidermonkey to a later point, when SM remaps memory to be
writable. On recent versions of HOS I observed that the `PROT_WRITE`
permission was silently ignored by mprotect, which lead to a crash later
on the first attempt to write to the memory region.
It's not exactly easy to determine if one can write to a memory location
(if mprotect lies to you), but we can use `read` to check if the memory
region is writable (without triggering a segfault), since `read` will
return an error for invalid addresses (which is possible since the
writing is handled in the kernel).

Since this solution does add more unsafe code than before, we only use
this detection on OpenHarmony, although we could use it on more
platforms later if there are other platforms which also may have JIT
forbidden.

Testing: Removing the explicit `--pref js_disable_jit=true` means the
detection is tested in CI.
Fixes: #40029

---------

Signed-off-by: Jonathan Schwender <schwenderjonathan@gmail.com>
Signed-off-by: Jonathan Schwender <55576758+jschwe@users.noreply.github.com>
Co-authored-by: Sam <16504129+sagudev@users.noreply.github.com>
2025-10-24 18:03:29 +00:00
..
2025-10-24 18:03:29 +00:00

This directory contains various Python modules used to support servo development.

servo

servo-specific python code e.g. implementations of mach commands. This is the canonical repository for this code.

tidy

servo-tidy is used to check licenses, line lengths, whitespace, ruff on Python files, lock file versions, and more.

wpt

servo-wpt is a module with support scripts for running, importing, exporting, updating manifests, and updating expectations for WPT tests.