Subject: [PATCH 2/3] arm64: Treat handle_arch_irq as a function pointer

From: [email-masked] (Will Deacon)
Date: Tue, 22 Apr 2014 11:48:06 +0100

On Fri, Apr 18, 2014 at 01:47:02AM +0100, Laura Abbott wrote:
> handle_arch_irq isn't actually text, it's just a function
> pointer. It doesn't need to be stored in the text section
> and doing so causes problems if we ever want to make the
> kernel text readonly. Move it to the data section.
> 
> Change-Id: I682ff82f5c8c429129dd81bbcc91571f278c62e2
> Signed-off-by: Laura Abbott <[email-masked]>
> ---
>  arch/arm64/kernel/entry.S | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
> index 39ac630..5051f30 100644
> --- a/arch/arm64/kernel/entry.S
> +++ b/arch/arm64/kernel/entry.S
> @@ -139,7 +139,8 @@ tsk	.req	x28		// current thread_info
>   * Interrupt handling.
>   */
>  	.macro	irq_handler
> -	ldr	x1, handle_arch_irq
> +	ldr	x1, =handle_arch_irq
> +	ldr	x1, [x1]
>  	mov	x0, sp
>  	blr	x1
>  	.endm
> @@ -678,5 +679,6 @@ ENTRY(sys_rt_sigreturn_wrapper)
>  	b	sys_rt_sigreturn
>  ENDPROC(sys_rt_sigreturn_wrapper)
>  
> +.data
>  ENTRY(handle_arch_irq)

Probably worth dropping the ENTRY directive if we're putting this in .data
and using an explicit .align instead.

Will