1 files changed, 23 insertions, 39 deletions

diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index c6b1f3b96f45..223b093c9440 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -58,14 +58,6 @@ unsigned long __stack_chk_guard __read_mostly;
 EXPORT_SYMBOL(__stack_chk_guard);
 #endif
 
-void soft_restart(unsigned long addr)
-{
-	setup_mm_for_reboot();
-	cpu_soft_restart(virt_to_phys(cpu_reset), addr);
-	/* Should never get here */
-	BUG();
-}
-
 /*
  * Function pointers to optional machine specific functions
  */
@@ -136,9 +128,7 @@ void machine_power_off(void)
 
 /*
  * Restart requires that the secondary CPUs stop performing any activity
- * while the primary CPU resets the system. Systems with a single CPU can
- * use soft_restart() as their machine descriptor's .restart hook, since that
- * will cause the only available CPU to reset. Systems with multiple CPUs must
+ * while the primary CPU resets the system. Systems with multiple CPUs must
  * provide a HW restart implementation, to ensure that all CPUs reset at once.
  * This is required so that any code running after reset on the primary CPU
  * doesn't have to co-ordinate with other CPUs to ensure they aren't still
@@ -243,7 +233,8 @@ void release_thread(struct task_struct *dead_task)
 
 int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
 {
-	fpsimd_preserve_current_state();
+	if (current->mm)
+		fpsimd_preserve_current_state();
 	*dst = *src;
 	return 0;
 }
@@ -254,35 +245,35 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 		unsigned long stk_sz, struct task_struct *p)
 {
 	struct pt_regs *childregs = task_pt_regs(p);
-	unsigned long tls = p->thread.tp_value;
 
 	memset(&p->thread.cpu_context, 0, sizeof(struct cpu_context));
 
 	if (likely(!(p->flags & PF_KTHREAD))) {
 		*childregs = *current_pt_regs();
 		childregs->regs[0] = 0;
-		if (is_compat_thread(task_thread_info(p))) {
-			if (stack_start)
+
+		/*
+		 * Read the current TLS pointer from tpidr_el0 as it may be
+		 * out-of-sync with the saved value.
+		 */
+		asm("mrs %0, tpidr_el0" : "=r" (*task_user_tls(p)));
+
+		if (stack_start) {
+			if (is_compat_thread(task_thread_info(p)))
 				childregs->compat_sp = stack_start;
-		} else {
-			/*
-			 * Read the current TLS pointer from tpidr_el0 as it may be
-			 * out-of-sync with the saved value.
-			 */
-			asm("mrs %0, tpidr_el0" : "=r" (tls));
-			if (stack_start) {
-				/* 16-byte aligned stack mandatory on AArch64 */
-				if (stack_start & 15)
-					return -EINVAL;
+			/* 16-byte aligned stack mandatory on AArch64 */
+			else if (stack_start & 15)
+				return -EINVAL;
+			else
 				childregs->sp = stack_start;
-			}
 		}
+
 		/*
 		 * If a TLS pointer was passed to clone (4th argument), use it
 		 * for the new thread.
 		 */
 		if (clone_flags & CLONE_SETTLS)
-			tls = childregs->regs[3];
+			p->thread.tp_value = childregs->regs[3];
 	} else {
 		memset(childregs, 0, sizeof(struct pt_regs));
 		childregs->pstate = PSR_MODE_EL1h;
@@ -291,7 +282,6 @@ int copy_thread(unsigned long clone_flags, unsigned long stack_start,
 	}
 	p->thread.cpu_context.pc = (unsigned long)ret_from_fork;
 	p->thread.cpu_context.sp = (unsigned long)childregs;
-	p->thread.tp_value = tls;
 
 	ptrace_hw_copy_thread(p);
 
@@ -302,18 +292,12 @@ static void tls_thread_switch(struct task_struct *next)
 {
 	unsigned long tpidr, tpidrro;
 
-	if (!is_compat_task()) {
-		asm("mrs %0, tpidr_el0" : "=r" (tpidr));
-		current->thread.tp_value = tpidr;
-	}
+	asm("mrs %0, tpidr_el0" : "=r" (tpidr));
+	*task_user_tls(current) = tpidr;
 
-	if (is_compat_thread(task_thread_info(next))) {
-		tpidr = 0;
-		tpidrro = next->thread.tp_value;
-	} else {
-		tpidr = next->thread.tp_value;
-		tpidrro = 0;
-	}
+	tpidr = *task_user_tls(next);
+	tpidrro = is_compat_thread(task_thread_info(next)) ?
+		  next->thread.tp_value : 0;
 
 	asm(
 	"	msr	tpidr_el0, %0\n"