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authorColin Cross <ccross@android.com>2012-05-05 20:58:13 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-05-06 11:10:41 +0100
commitfde165b2a29673aabf18ceff14dea1f1cfb0daad (patch)
treeb1f12719f3d4f479d72fc6affb9c11cb3b15375b /arch/arm/kernel/smp.c
parent2f978366984a418f38fcf44137be1fbc5a89cfd9 (diff)
downloadvexpress-lsk-fde165b2a29673aabf18ceff14dea1f1cfb0daad.tar.gz
ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd
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. Cc: <stable@vger.kernel.org> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/kernel/smp.c')
-rw-r--r--arch/arm/kernel/smp.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index f6a4d32b042..8f464465977 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -251,8 +251,6 @@ 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.
@@ -264,6 +262,8 @@ 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();