Bug 216545 - Add an option to disable sv57 support
Summary: Add an option to disable sv57 support
Status: NEW
Alias: None
Product: Platform Specific/Hardware
Classification: Unclassified
Component: Other (show other bugs)
Hardware: RISC-V Linux
: P1 normal
Assignee: platform_other
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2022-10-01 09:59 UTC by Felix Yan
Modified: 2022-10-01 10:03 UTC (History)
1 user (show)

See Also:
Kernel Version: 5.18,5.19,6.0,6.1
Subsystem:
Regression: No
Bisected commit-id:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Description Felix Yan 2022-10-01 09:59:47 UTC 
Since Linux 5.18, sv57 was added for 64-bit RISC-V architecture. Since sv57 is already supported as SATP mode in qemu-system-riscv64 too, Linux uses sv57 automatically and there is no easy option to disable it. This unfortunately breaks userspace programs as at least OpenJDK and v8 still have no support for this mode.

Considering that userspace programs still need significant time to adapt, it is beneficial to provide an option to disable kernel support for sv57 and build distribution kernels with it.

(Ubuntu already started to patch their kernel for this: http://sprunge.us/WGq6Pm and will most likely disable sv57 for kinetic.)
Note You need to log in before you can comment on or make changes to this bug.