Commit 4bea3418 authored Mar 28, 2010 by Matt Fleming Committed by Paul Mundt Mar 29, 2010

sh: Enable the mmu in start_secondary()



For the boot, enable_mmu() is called from setup_arch() but we don't call
setup_arch() for any of the other cpus. So turn on the non-boot cpu's
mmu inside of start_secondary().

I noticed this bug on an SMP board when trying to map I/O memory
(smsc911x registers) into the kernel address space. Since the Address
Translation bit in MMUCR wasn't set, accessing the virtual address where
the smsc911x registers were supposedly mapped actually performed a
physical address access.

Signed-off-by: Matt Fleming <matt@console-pimps.org>
Cc: stable@kernel.org
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

parent d5ab7803

arch/sh/kernel/smp.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -69,6 +69,7 @@ asmlinkage void __cpuinit start_secondary(void)
		unsigned int cpu;
		struct mm_struct *mm = &init_mm;

		enable_mmu();
		atomic_inc(&mm->mm_count);
		atomic_inc(&mm->mm_users);
		current->active_mm = mm;

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