[PATCH] ARM: Fix data abort accessing proc_info from __lookup_processor_type (Re: [PATCH 03/10] ARM: hotplug cpu: Keep processor information, startup code & __lookup_processor_type)
Tony Lindgren
tony at atomide.com
Sat Oct 23 14:18:19 EDT 2010
* Russell King - ARM Linux <linux at arm.linux.org.uk> [101023 01:21]:
> On Fri, Oct 22, 2010 at 11:51:08AM -0700, Tony Lindgren wrote:
> > diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
> > index 1953e3d..a58b91d 100644
> > --- a/arch/arm/kernel/vmlinux.lds.S
> > +++ b/arch/arm/kernel/vmlinux.lds.S
> > @@ -114,6 +114,7 @@ SECTIONS
> > *(.glue_7)
> > *(.glue_7t)
> > *(.got) /* Global offset table */
> > + . = ALIGN(4);
> > ARM_CPU_KEEP(PROC_INFO)
>
> The got table should also be word aligned - but the kernel doesn't use
> one. In any case, it would be a good idea to place it before the .got.
OK, updated patch below.
By moving ARM_CPU_KEEP(PROC_INFO) around I've confirmed that it's
happening at rodata.*. Do you want also another align before .glue_7
as well?
Regards,
Tony
From: Tony Lindgren <tony at atomide.com>
Date: Fri, 22 Oct 2010 12:41:55 -0700
Subject: [PATCH] ARM: Fix data abort accessing proc_info from __lookup_processor_type
Commit 5085f3ff458521045f7e43da62b8c30ea7df2e82 added better support for
CONFIG_HOTPLUG_CPU by keeping proc_info around. However, depending on
the Kconfig options selected, this can make the booting fail mysteriously
early on.
Turns out a data abort can happen in __lookup_processor in ldmia r5 {r3, r4}.
When it happens the address loaded to r5 is not aligned. Fix the problem by
aligning proc_info.
Reported-by: Anand Gadiyar <gadiyar at ti.com>
Signed-off-by: Tony Lindgren <tony at atomide.com>
Tested-by: Anand Gadiyar <gadiyar at ti.com>
diff --git a/arch/arm/kernel/vmlinux.lds.S b/arch/arm/kernel/vmlinux.lds.S
index 1953e3d..cead889 100644
--- a/arch/arm/kernel/vmlinux.lds.S
+++ b/arch/arm/kernel/vmlinux.lds.S
@@ -113,6 +113,7 @@ SECTIONS
*(.rodata.*)
*(.glue_7)
*(.glue_7t)
+ . = ALIGN(4);
*(.got) /* Global offset table */
ARM_CPU_KEEP(PROC_INFO)
}
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