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| author | Colin Cross <ccross@android.com> | 2012-05-05 20:58:13 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-05-21 09:39:58 -0700 |
| commit | cb68af469fa453694a03553c6efd0681f2c5264f (patch) | |
| tree | 226e40edf0684a01c36d65a8265587ffa410278f /arch/arm | |
| parent | 6007ca9964e4607fd5835be19391b1d85ebc07a4 (diff) | |
| download | lwn-cb68af469fa453694a03553c6efd0681f2c5264f.tar.gz lwn-cb68af469fa453694a03553c6efd0681f2c5264f.zip | |
ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd
commit fde165b2a29673aabf18ceff14dea1f1cfb0daad upstream.
Commit 4e8ee7de227e3ab9a72040b448ad728c5428a042 (ARM: SMP: use
idmap_pgd for mapping MMU enable during secondary booting)
switched secondary boot to use idmap_pgd, which is initialized
during early_initcall, instead of a page table initialized during
__cpu_up. This causes idmap_pgd to contain the static mappings
but be missing all dynamic mappings.
If a console is registered that creates a dynamic mapping, the
printk in secondary_start_kernel will trigger a data abort on
the missing mapping before the exception handlers have been
initialized, leading to a hang. Initial boot is not affected
because no consoles have been registered, and resume is usually
not affected because the offending console is suspended.
Onlining a cpu with hotplug triggers the problem.
A workaround is to the printk in secondary_start_kernel until
after the page tables have been switched back to init_mm.
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/kernel/smp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index e7f92a4321f3..fea97f64221b 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -279,8 +279,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void) struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id(); - printk("CPU%u: Booted secondary processor\n", cpu); - /* * All kernel threads share the same mm context; grab a * reference and switch to it. @@ -292,6 +290,8 @@ asmlinkage void __cpuinit secondary_start_kernel(void) enter_lazy_tlb(mm, current); local_flush_tlb_all(); + printk("CPU%u: Booted secondary processor\n", cpu); + cpu_init(); preempt_disable(); trace_hardirqs_off(); |