1 files changed, 60 insertions, 4 deletions

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 2dc0f8482210..b2adcce7bc18 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -49,6 +49,7 @@
 #include <linux/notifier.h>
 #include <trace/events/power.h>
 #include <linux/percpu.h>
+#include <linux/thread_info.h>
 
 #include <asm/alternative.h>
 #include <asm/compat.h>
@@ -170,6 +171,39 @@ void machine_restart(char *cmd)
 	while (1);
 }
 
+static void print_pstate(struct pt_regs *regs)
+{
+	u64 pstate = regs->pstate;
+
+	if (compat_user_mode(regs)) {
+		printk("pstate: %08llx (%c%c%c%c %c %s %s %c%c%c)\n",
+			pstate,
+			pstate & COMPAT_PSR_N_BIT ? 'N' : 'n',
+			pstate & COMPAT_PSR_Z_BIT ? 'Z' : 'z',
+			pstate & COMPAT_PSR_C_BIT ? 'C' : 'c',
+			pstate & COMPAT_PSR_V_BIT ? 'V' : 'v',
+			pstate & COMPAT_PSR_Q_BIT ? 'Q' : 'q',
+			pstate & COMPAT_PSR_T_BIT ? "T32" : "A32",
+			pstate & COMPAT_PSR_E_BIT ? "BE" : "LE",
+			pstate & COMPAT_PSR_A_BIT ? 'A' : 'a',
+			pstate & COMPAT_PSR_I_BIT ? 'I' : 'i',
+			pstate & COMPAT_PSR_F_BIT ? 'F' : 'f');
+	} else {
+		printk("pstate: %08llx (%c%c%c%c %c%c%c%c %cPAN %cUAO)\n",
+			pstate,
+			pstate & PSR_N_BIT ? 'N' : 'n',
+			pstate & PSR_Z_BIT ? 'Z' : 'z',
+			pstate & PSR_C_BIT ? 'C' : 'c',
+			pstate & PSR_V_BIT ? 'V' : 'v',
+			pstate & PSR_D_BIT ? 'D' : 'd',
+			pstate & PSR_A_BIT ? 'A' : 'a',
+			pstate & PSR_I_BIT ? 'I' : 'i',
+			pstate & PSR_F_BIT ? 'F' : 'f',
+			pstate & PSR_PAN_BIT ? '+' : '-',
+			pstate & PSR_UAO_BIT ? '+' : '-');
+	}
+}
+
 void __show_regs(struct pt_regs *regs)
 {
 	int i, top_reg;
@@ -186,10 +220,9 @@ void __show_regs(struct pt_regs *regs)
 	}
 
 	show_regs_print_info(KERN_DEFAULT);
-	print_symbol("PC is at %s\n", instruction_pointer(regs));
-	print_symbol("LR is at %s\n", lr);
-	printk("pc : [<%016llx>] lr : [<%016llx>] pstate: %08llx\n",
-	       regs->pc, lr, regs->pstate);
+	print_pstate(regs);
+	print_symbol("pc : %s\n", regs->pc);
+	print_symbol("lr : %s\n", lr);
 	printk("sp : %016llx\n", sp);
 
 	i = top_reg;
@@ -241,11 +274,27 @@ void release_thread(struct task_struct *dead_task)
 {
 }
 
+void arch_release_task_struct(struct task_struct *tsk)
+{
+	fpsimd_release_task(tsk);
+}
+
+/*
+ * src and dst may temporarily have aliased sve_state after task_struct
+ * is copied.  We cannot fix this properly here, because src may have
+ * live SVE state and dst's thread_info may not exist yet, so tweaking
+ * either src's or dst's TIF_SVE is not safe.
+ *
+ * The unaliasing is done in copy_thread() instead.  This works because
+ * dst is not schedulable or traceable until both of these functions
+ * have been called.
+ */
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
 	if (current->mm)
 		fpsimd_preserve_current_state();
 	*dst = *src;
+
 	return 0;
 }
 
@@ -258,6 +307,13 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 
 	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 
+	/*
+	 * Unalias p->thread.sve_state (if any) from the parent task
+	 * and disable discard SVE state for p:
+	 */
+	clear_tsk_thread_flag(p, TIF_SVE);
+	p->thread.sve_state = NULL;
+
 	if (likely(!(p->flags & PF_KTHREAD))) {
 		*childregs = *current_pt_regs();
 		childregs->regs[0] = 0;