forked from luck/tmp_suning_uos_patched
ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd
Commit 4e8ee7de22
(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.
Cc: <stable@vger.kernel.org>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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parent
2f97836698
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@ -251,8 +251,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
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struct mm_struct *mm = &init_mm;
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unsigned int cpu = smp_processor_id();
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printk("CPU%u: Booted secondary processor\n", cpu);
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/*
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* All kernel threads share the same mm context; grab a
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* reference and switch to it.
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@ -264,6 +262,8 @@ asmlinkage void __cpuinit secondary_start_kernel(void)
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enter_lazy_tlb(mm, current);
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local_flush_tlb_all();
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printk("CPU%u: Booted secondary processor\n", cpu);
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cpu_init();
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preempt_disable();
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trace_hardirqs_off();
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