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authorRussell King <rmk+kernel@arm.linux.org.uk>2015-09-09 21:19:49 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2015-09-09 23:26:44 +0100
commitaf4cb25df93d2e7a97d65db2bfacaa4400988dea (patch)
treea19e89d89937303b0196351636d81df712c9a456 /arch/arm/kernel
parent296254f3223d201f2aa53f5f717eedfdc63f3db8 (diff)
downloadlinux-linaro-stable-af4cb25df93d2e7a97d65db2bfacaa4400988dea.tar.gz
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 <ariel@vanguardiasur.com.ar> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel')
-rw-r--r--arch/arm/kernel/process.c2
1 files changed, 2 insertions, 0 deletions
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();