8000 Aarch64: 4KB granule check fails with FEAT_LPA2 · Issue #1461 · seL4/seL4 · GitHub
[go: up one dir, main page]
More Web Proxy on the site http://driver.im/
Skip to content

Aarch64: 4KB granule check fails with FEAT_LPA2 #1461

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for Gi 8000 tHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom
Open
fischerer opened this issue May 19, 2025 · 2 comments
Open

Aarch64: 4KB granule check fails with FEAT_LPA2 #1461

fischerer opened this issue May 19, 2025 · 2 comments

Comments

@fischerer
Copy link

If FEAT_LPA2 is implemented, 4KB granule support is indicated with TGran4 (ID_AA64MMFR0_EL1[31:28]) bits set to 0b0001, instead of 0b0000.

Workaround: Update granule check to if (granule == 0b1111).
@Indanz
Copy link
Contributor
Indanz commented May 19, 2025

Yes, they added 1 and said 0xf means not supported, while the old standard only mentioned 0 as meaning 4k supported. So the most conservative check would be checking against only 0 and 1. But the old implementations probably did return 0xf if 4k wasn't supported, if there was ever any such implementation, so just checking 0xf is fine too.

@Indanz
Copy link
Contributor
Indanz commented May 19, 2025

Would like like to create a pull request or would you prefer me to do it? Advantage of you doing it is that I can review your change, while someone else has to review my PR.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Assignees
No one assigned
Labels
None yet
Projects
None yet
Milestone
No milestone
Development

No branches or pull requests
2 participants
@Indanz @fischerer
0