[PATCH v4 2/8] ARM: kexec: ensure new kernel is entered in ARM state

Nicolas Pitre nico at fluxnic.net
Tue Aug 23 21:28:12 EDT 2011


On Tue, 23 Aug 2011, Will Deacon wrote:

> Commit 540b5738 ("ARM: 6999/1: head, zImage: Always Enter the kernel in
> ARM state") mandates that the kernel should be entered in ARM state.
> 
> If a Thumb-2 kernel kexecs a new kernel image, we need to ensure that
> we change state when branching to the new code. This patch replaces a
> mov pc, lr with a bx lr so that we transition to ARM state if need be.

This will break kexec support on ARMv4 targets.  No idea if any ARMv4 
target uses kexec though.

> Signed-off-by: Will Deacon <will.deacon at arm.com>
> ---
>  arch/arm/kernel/relocate_kernel.S |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/kernel/relocate_kernel.S b/arch/arm/kernel/relocate_kernel.S
> index 9cf4cbf..0908633 100644
> --- a/arch/arm/kernel/relocate_kernel.S
> +++ b/arch/arm/kernel/relocate_kernel.S
> @@ -57,7 +57,7 @@ relocate_new_kernel:
>  	mov r0,#0
>  	ldr r1,kexec_mach_type
>  	ldr r2,kexec_boot_atags
> -	mov pc,lr
> +	bx lr
>  
>  	.align
>  
> -- 
> 1.7.0.4
> 
> 
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