Re: [PATCH stable/4.0.y] ARM: 8325/1: exynos: move resume code to .text section

[Ben Hutchings <ben@decadent.org.uk>]

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On Tue, 2015-06-02 at 19:42 -0700, Kevin Hilman wrote:
> From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> 
> This code calls cpu_resume() using a straight branch (b), so
> now that we have moved cpu_resume() back to .text, this should
> be moved there as well. Any direct references to symbols that will
> remain in the .data section are replaced with explicit PC-relative
> references.

I don't get it.  cpu_resume() is still in the .data section in 4.0.
This appears to depend on:

commit d0776aff9a38b1390cc06ffc2c4dcf6ece7c05b9
Author: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date:   Wed Mar 25 07:39:21 2015 +0100

    ARM: 8324/1: move cpu_resume() to .text section

Ben.

> Acked-by: Nicolas Pitre <nico@linaro.org>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> (cherry picked from commit 12833bacf5d904c2dac0c3f52b2ebde5f2c5a2bc)
> Cc: <stable@vger.kernel.org> # v4.0+
> Signed-off-by: Kevin Hilman <khilman@linaro.org>
> ---
> This fixes compile errors on stable/linux-4.0.y when building for ARM
> using multi_v7_defconfig + CONFIG_THUMB2_KERNEL=y:
> 
> ../arch/arm/mach-exynos/sleep.S:72: Error: invalid immediate for address calculation (value = 0x00000004)
> ../arch/arm/mach-exynos/sleep.S:74: Error: invalid immediate for address calculation (value = 0x00000004)
>  
>  arch/arm/mach-exynos/sleep.S | 31 ++++++++++++++++---------------
>  1 file changed, 16 insertions(+), 15 deletions(-)
> 
> diff --git a/arch/arm/mach-exynos/sleep.S b/arch/arm/mach-exynos/sleep.S
> index 31d25834b9c4..cf950790fbdc 100644
> --- a/arch/arm/mach-exynos/sleep.S
> +++ b/arch/arm/mach-exynos/sleep.S
> @@ -23,14 +23,7 @@
>  #define CPU_MASK	0xff0ffff0
>  #define CPU_CORTEX_A9	0x410fc090
>  
> -	/*
> -	 * The following code is located into the .data section. This is to
> -	 * allow l2x0_regs_phys to be accessed with a relative load while we
> -	 * can't rely on any MMU translation. We could have put l2x0_regs_phys
> -	 * in the .text section as well, but some setups might insist on it to
> -	 * be truly read-only. (Reference from: arch/arm/kernel/sleep.S)
> -	 */
> -	.data
> +	.text
>  	.align
>  
>  	/*
> @@ -69,10 +62,12 @@ ENTRY(exynos_cpu_resume_ns)
>  	cmp	r0, r1
>  	bne	skip_cp15
>  
> -	adr	r0, cp15_save_power
> +	adr	r0, _cp15_save_power
>  	ldr	r1, [r0]
> -	adr	r0, cp15_save_diag
> +	ldr	r1, [r0, r1]
> +	adr	r0, _cp15_save_diag
>  	ldr	r2, [r0]
> +	ldr	r2, [r0, r2]
>  	mov	r0, #SMC_CMD_C15RESUME
>  	dsb
>  	smc	#0
> @@ -118,14 +113,20 @@ skip_l2x0:
>  skip_cp15:
>  	b	cpu_resume
>  ENDPROC(exynos_cpu_resume_ns)
> +
> +	.align
> +_cp15_save_power:
> +	.long	cp15_save_power - .
> +_cp15_save_diag:
> +	.long	cp15_save_diag - .
> +#ifdef CONFIG_CACHE_L2X0
> +1:	.long	l2x0_saved_regs - .
> +#endif /* CONFIG_CACHE_L2X0 */
> +
> +	.data
>  	.globl cp15_save_diag
>  cp15_save_diag:
>  	.long	0	@ cp15 diagnostic
>  	.globl cp15_save_power
>  cp15_save_power:
>  	.long	0	@ cp15 power control
> -
> -#ifdef CONFIG_CACHE_L2X0
> -	.align
> -1:	.long	l2x0_saved_regs - .
> -#endif /* CONFIG_CACHE_L2X0 */

-- 
Ben Hutchings
Never put off till tomorrow what you can avoid all together.

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