| Date | Thu, 22 Apr 2010 12:07:59 -0700 | From | Greg KH <> | Subject | [028/197] sh: Enable the mmu in start_secondary() |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Matt Fleming <matt@console-pimps.org>
commit 4bea3418c737891894b9d3d3e9f8bbd67d66fa38 upstream.
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> Signed-off-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- a/arch/sh/kernel/smp.c +++ b/arch/sh/kernel/smp.c @@ -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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