9 Dec
2024
9 Dec
'24
12:36 p.m.
On Mon, Dec 09, 2024 at 06:52:37PM +0800, Weizhao Ouyang wrote:
When using svcr_in to check ZA and Streaming Mode, we should make sure that the value in x2 is correct, otherwise it may trigger an Illegal instruction if FEAT_SVE and !FEAT_SME.
// Set SVCR if we're doing SME
- cbz x1, 1f adrp x2, svcr_in ldr x2, [x2, :lo12:svcr_in]
- cbz x1, 1f msr S3_3_C4_C2_2, x2
This is against an older verison of the code so wouldn't apply now. It's not also checking the value of SVCR, this is checking the SME flag passed in via x1. You can see that the SVCR value is loaded into x2 but the check is against x1.