From af4cb25df93d2e7a97d65db2bfacaa4400988dea Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 9 Sep 2015 21:19:49 +0100 Subject: [PATCH] ARM: uaccess: fix undefined instruction on ARMv7M/noMMU The use of get_domain() in copy_thread() results in an oops on ARMv7M/noMMU systems. The thread cpu_domain value is only used when CONFIG_CPU_USE_DOMAINS is enabled, so there's no need to save the value in copy_thread() except when this is enabled, and this option will never be enabled on these platforms. Unhandled exception: IPSR = 00000006 LR = fffffff1 CPU: 0 PID: 0 Comm: swapper Not tainted 4.2.0-next-20150909-00001-gb8ec5ad #41 Hardware name: NXP LPC18xx/43xx (Device Tree) task: 2823fbe0 ti: 2823c000 task.ti: 2823c000 PC is at copy_thread+0x18/0x92 LR is at copy_thread+0x19/0x92 pc : [<2800a46e>] lr : [<2800a46f>] psr: 4100000b sp : 2823df00 ip : 00000000 fp : 287c81c0 r10: 00000000 r9 : 00800300 r8 : 287c8000 r7 : 287c8000 r6 : 2818908d r5 : 00000000 r4 : 287ca000 r3 : 00000000 r2 : 00000000 r1 : fffffff0 r0 : 287ca048 xPSR: 4100000b Reported-by: Ariel D'Alessandro Signed-off-by: Russell King --- arch/arm/kernel/process.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 3f18098dfd08..e550a4541f48 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -233,6 +233,7 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start, memset(&thread->cpu_context, 0, sizeof(struct cpu_context_save)); +#ifdef CONFIG_CPU_USE_DOMAINS /* * Copy the initial value of the domain access control register * from the current thread: thread->addr_limit will have been @@ -240,6 +241,7 @@ copy_thread(unsigned long clone_flags, unsigned long stack_start, * kernel/fork.c */ thread->cpu_domain = get_domain(); +#endif if (likely(!(p->flags & PF_KTHREAD))) { *childregs = *current_pt_regs(); -- 2.11.0