[PATCH] arm64/sme: Fix EFI save/restore

[Mark Brown]

The EFI save/restore code is confused. When saving the check for saving
FFR is inverted due to confusion with the streaming mode check, and when
restoring we check if we need to restore FFR by checking the percpu
efi_sm_state without the required wrapper rather than based on the
combination of FA64 support and streaming mode.

Fixes: e0838f6373e5 ("arm64/sme: Save and restore streaming mode over EFI runtime calls")
Reported-by: kernel test robot <lkp at intel.com>
Signed-off-by: Mark Brown <broonie at kernel.org>
---

Compile tested only at this point.

 arch/arm64/kernel/fpsimd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c
index 819979398127..3c66a061ff6f 100644
--- a/arch/arm64/kernel/fpsimd.c
+++ b/arch/arm64/kernel/fpsimd.c
@@ -1916,10 +1916,11 @@ void __efi_fpsimd_begin(void)
 			if (system_supports_sme()) {
 				svcr = read_sysreg_s(SYS_SVCR);
 
-				if (!system_supports_fa64())
-					ffr = svcr & SVCR_SM_MASK;
+				__this_cpu_write(efi_sm_state,
+						 svcr & SVCR_SM_MASK);
 
-				__this_cpu_write(efi_sm_state, ffr);
+				if (!system_supports_fa64())
+					ffr = !(svcr & SVCR_SM_MASK);
 			}
 
 			sve_save_state(sve_state + sve_ffr_offset(sve_max_vl()),
@@ -1965,7 +1966,7 @@ void __efi_fpsimd_end(void)
 							   0,
 							   SVCR_SM_MASK);
 					if (!system_supports_fa64())
-						ffr = efi_sm_state;
+						ffr = false;
 				}
 			}
 
-- 
2.30.2