arm64/sme: Restore SMCR_EL1.EZT0 on exit from suspend

The fields in SMCR_EL1 reset to an architecturally UNKNOWN value. Since we do not otherwise manage the traps configured in this register at runtime we need to reconfigure them after a suspend in case nothing else was kind enough to preserve them for us. Do so for SMCR_EL1.EZT0. Fixes: d4913ee ("arm64/sme: Add basic enumeration for SME2") Reported-by: Jackson Cooper-Driver <[email protected]> Signed-off-by: Mark Brown <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>
AsahiLinux · Feb 20, 2024 · d7b77a0 · d7b77a0
1 parent 9533864
commit d7b77a0
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
@@ -1320,6 +1320,8 @@ void sme_suspend_exit(void)
 
 	if (system_supports_fa64())
 		smcr |= SMCR_ELx_FA64;
+	if (system_supports_sme2())
+		smcr |= SMCR_ELx_EZT0;
 
 	write_sysreg_s(smcr, SYS_SMCR_EL1);
 	write_sysreg_s(0, SYS_SMPRI_EL1);