Bug 221198 – CeilingOnPageSize too low for Loongson CPUs

• Status: RESOLVED
• Resolution: FIXED
• Component: JavaScriptCore

[Alberto Garcia]

CeilingOnPageSize is set to 4KB for MIPS on Linux, but that value is not permitted on Loongson CPUs which have a 16KB page size:

https://sources.debian.org/src/linux/5.10.9-1/arch/mips/Kconfig/#L2213-L2215

[Xan Lopez]

Our guess is that we are crashing in WTF::pageSize():

        RELEASE_ASSERT_WITH_MESSAGE(s_pageSize <= CeilingOnPageSize, "CeilingOnPageSize is too low, raise it in PageBlock.h!");

For Loongson CPUs that will be 16 <= 4, which won't work.

We can change the general ceiling value for MIPS to something else, at least 16KB, or try to detect Loongson CPUs and change it just for those.

[Alberto Garcia]

(In reply to Xan Lopez from comment #1)
> We can change the general ceiling value for MIPS to something else,
> at least 16KB, or try to detect Loongson CPUs and change it just for
> those.

For distributions I don't think the latter is an option, because
there's no guarantee that the machine where the package is built is
the same where it is installed and run.

But I can patch that downstream if there's no good general solution.

[Radar WebKit Bug Importer]

<rdar://problem/74089683>

[Alberto Garcia]

This was fixed for 32-bit MIPS in r276583 (bug 225030), I think we should also do it for MIPS64.

[Michael Catanzaro]

(In reply to Alberto Garcia from comment #4)
> This was fixed for 32-bit MIPS in r276583 (bug 225030), I think we should
> also do it for MIPS64.

Do it!

[Alberto Garcia]

Created attachment 428747 [details]
Patch

[EWS]

Committed r277551 (237779@main): <https://commits.webkit.org/237779@main>

All reviewed patches have been landed. Closing bug and clearing flags on attachment 428747 [details].

[Michael Catanzaro]

*** Bug 223721 has been marked as a duplicate of this bug. ***