Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 fixes from Catalin Marinas:
 "More SVE/SME fixes for ptrace() and for the (potentially future) case
  where SME is implemented in hardware without SVE support"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64/fpsimd: Sync and zero pad FPSIMD state for streaming SVE
  arm64/fpsimd: Sync FPSIMD state with SVE for SME only systems
  arm64/ptrace: Don't enable SVE when setting streaming SVE
  arm64/ptrace: Flush FP state when setting ZT0
  arm64/fpsimd: Clear SME state in the target task when setting the VL

Author: torvalds

arch/arm64/kernel/fpsimd.c

@@ -679,7 +679,7 @@ static void fpsimd_to_sve(struct task_struct *task)
 	void *sst = task->thread.sve_state;
 	struct user_fpsimd_state const *fst = &task->thread.uw.fpsimd_state;
 
-	if (!system_supports_sve())
+	if (!system_supports_sve() && !system_supports_sme())
 		return;
 
 	vq = sve_vq_from_vl(thread_get_cur_vl(&task->thread));
@@ -705,7 +705,7 @@ static void sve_to_fpsimd(struct task_struct *task)
 	unsigned int i;
 	__uint128_t const *p;
 
-	if (!system_supports_sve())
+	if (!system_supports_sve() && !system_supports_sme())
 		return;
 
 	vl = thread_get_cur_vl(&task->thread);
@@ -835,7 +835,8 @@ void sve_sync_from_fpsimd_zeropad(struct task_struct *task)
 	void *sst = task->thread.sve_state;
 	struct user_fpsimd_state const *fst = &task->thread.uw.fpsimd_state;
 
-	if (!test_tsk_thread_flag(task, TIF_SVE))
+	if (!test_tsk_thread_flag(task, TIF_SVE) &&
+	    !thread_sm_enabled(&task->thread))
 		return;
 
 	vq = sve_vq_from_vl(thread_get_cur_vl(&task->thread));
@@ -909,7 +910,7 @@ int vec_set_vector_length(struct task_struct *task, enum vec_type type,
 			 */
 			task->thread.svcr &= ~(SVCR_SM_MASK |
 					       SVCR_ZA_MASK);
-			clear_thread_flag(TIF_SME);
+			clear_tsk_thread_flag(task, TIF_SME);
 			free_sme = true;
 		}
 	}

arch/arm64/kernel/ptrace.c

@@ -932,11 +932,13 @@ static int sve_set_common(struct task_struct *target,
 	/*
 	 * Ensure target->thread.sve_state is up to date with target's
 	 * FPSIMD regs, so that a short copyin leaves trailing
-	 * registers unmodified.  Always enable SVE even if going into
-	 * streaming mode.
+	 * registers unmodified.  Only enable SVE if we are
+	 * configuring normal SVE, a system with streaming SVE may not
+	 * have normal SVE.
 	 */
 	fpsimd_sync_to_sve(target);
-	set_tsk_thread_flag(target, TIF_SVE);
+	if (type == ARM64_VEC_SVE)
+		set_tsk_thread_flag(target, TIF_SVE);
 	target->thread.fp_type = FP_STATE_SVE;
 
 	BUILD_BUG_ON(SVE_PT_SVE_OFFSET != sizeof(header));
@@ -1180,6 +1182,8 @@ static int zt_set(struct task_struct *target,
 	if (ret == 0)
 		target->thread.svcr |= SVCR_ZA_MASK;
 
+	fpsimd_flush_task_state(target);
+
 	return ret;
 }