From: Colin Cross Date: Sat, 5 May 2012 19:58:13 +0000 (+0100) Subject: ARM: 7414/1: SMP: prevent use of the console when using idmap_pgd X-Git-Tag: v3.2.17~13 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2f03a6bb3e9dc3a1b5fb10c7885033809896c4f9;p=pandora-kernel.git 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 Signed-off-by: Russell King Signed-off-by: Ben Hutchings --- Reading git-diff-tree failed