[Git pull request] fix to the vexpress/mcpm branch

[Lorenzo Pieralisi]

On Wed, Aug 14, 2013 at 03:25:14PM +0100, Nicolas Pitre wrote:
> On Tue, 13 Aug 2013, Olof Johansson wrote:
> 
> > Hi Nico,
> > 
> > On Mon, Aug 12, 2013 at 02:37:54PM -0400, Nicolas Pitre wrote:
> > > 
> > > Please pull the following:
> > > 
> > > 	git://git.linaro.org/people/nico/linux mcpm+tc2
> > > 
> > > which will update your vexpress/mcpm branch with one additional commit 
> > > fixing the build issue with CONFIG_FRAME_POINTER reported by RMK.  This 
> > > commit's SHA1 is 95fbdc9cf542.
> > 
> > So, I just replaced my branch with the one from Pawel, and the topmost patch
> > in your branch seems to no longer apply.
> 
> Weird.  It still applies perfectly here.
> 
> Here's the patch nevertheless.  Please apply ASAP as Lorenzo wishes to 
> base his next pull request on top of this.

Thanks Nico. For the records, I applied your patch against arm-soc
vexpress/mcpm and my pull request for the CPUidle driver still applies
cleanly on top of that branch, so there should not be anything to do on
my side, but I am here if anything goes wrong.

Lorenzo

> 
> ----- >8
> 
> From: Nicolas Pitre <nicolas.pitre at linaro.org>
> Date: Mon, 12 Aug 2013 12:47:13 -0400
> Subject: [PATCH] ARM: vexpress/MCPM: fix cache disable sequence when CONFIG_FRAME_POINTER=y
> 
> If CONFIG_FRAME_POINTER=y we hget the following error:
> 
> arch/arm/mach-vexpress/tc2_pm.c: In function 'tc2_pm_down':
> arch/arm/mach-vexpress/tc2_pm.c:200:1: error: fp cannot be used in asm here
> 
> Let's fix that by explicitly preserving r11 on the stack and removing it
> from the clobber list.
> 
> Reported-by: Russell King <rmk+kernel at arm.linux.org.uk>
> Reviewed-by: Dave Martin <Dave.Martin at arm.com>
> Signed-off-by: Nicolas Pitre <nico at linaro.org>
> 
> diff --git a/arch/arm/mach-vexpress/dcscb.c b/arch/arm/mach-vexpress/dcscb.c
> index 85fffa702f..3a6384c6c4 100644
> --- a/arch/arm/mach-vexpress/dcscb.c
> +++ b/arch/arm/mach-vexpress/dcscb.c
> @@ -144,8 +144,13 @@ static void dcscb_power_down(void)
>  		 * Let's do it in the safest possible way i.e. with
>  		 * no memory access within the following sequence
>  		 * including to the stack.
> +		 *
> +		 * Note: fp is preserved to the stack explicitly prior doing
> +		 * this since adding it to the clobber list is incompatible
> +		 * with having CONFIG_FRAME_POINTER=y.
>  		 */
>  		asm volatile(
> +		"str	fp, [sp, #-4]! \n\t"
>  		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
>  		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
> @@ -156,9 +161,10 @@ static void dcscb_power_down(void)
>  		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
>  		"isb	\n\t"
> -		"dsb	"
> +		"dsb	\n\t"
> +		"ldr	fp, [sp], #4"
>  		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
> -		      "r9","r10","r11","lr","memory");
> +		      "r9","r10","lr","memory");
>  
>  		/*
>  		 * This is a harmless no-op.  On platforms with a real
> @@ -182,6 +188,7 @@ static void dcscb_power_down(void)
>  		 * Let's do it in the safest possible way as above.
>  		 */
>  		asm volatile(
> +		"str	fp, [sp, #-4]! \n\t"
>  		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
>  		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
> @@ -192,9 +199,10 @@ static void dcscb_power_down(void)
>  		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
>  		"isb	\n\t"
> -		"dsb	"
> +		"dsb	\n\t"
> +		"ldr	fp, [sp], #4"
>  		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
> -		      "r9","r10","r11","lr","memory");
> +		      "r9","r10","lr","memory");
>  	}
>  
>  	__mcpm_cpu_down(cpu, cluster);
> diff --git a/arch/arm/mach-vexpress/tc2_pm.c b/arch/arm/mach-vexpress/tc2_pm.c
> index ddd97dd4e9..2b7c93a724 100644
> --- a/arch/arm/mach-vexpress/tc2_pm.c
> +++ b/arch/arm/mach-vexpress/tc2_pm.c
> @@ -150,8 +150,13 @@ static void tc2_pm_down(u64 residency)
>  		 * Let's do it in the safest possible way i.e. with
>  		 * no memory access within the following sequence
>  		 * including the stack.
> +		 *
> +		 * Note: fp is preserved to the stack explicitly prior doing
> +		 * this since adding it to the clobber list is incompatible
> +		 * with having CONFIG_FRAME_POINTER=y.
>  		 */
>  		asm volatile(
> +		"str	fp, [sp, #-4]! \n\t"
>  		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
>  		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
> @@ -162,9 +167,10 @@ static void tc2_pm_down(u64 residency)
>  		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
>  		"isb	\n\t"
> -		"dsb	"
> +		"dsb	\n\t"
> +		"ldr	fp, [sp], #4"
>  		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
> -		      "r9","r10","r11","lr","memory");
> +		      "r9","r10","lr","memory");
>  
>  		cci_disable_port_by_cpu(mpidr);
>  
> @@ -185,6 +191,7 @@ static void tc2_pm_down(u64 residency)
>  		 * Let's do it in the safest possible way as above.
>  		 */
>  		asm volatile(
> +		"str	fp, [sp, #-4]! \n\t"
>  		"mrc	p15, 0, r0, c1, c0, 0	@ get CR \n\t"
>  		"bic	r0, r0, #"__stringify(CR_C)" \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 0	@ set CR \n\t"
> @@ -195,9 +202,10 @@ static void tc2_pm_down(u64 residency)
>  		"bic	r0, r0, #(1 << 6)	@ disable local coherency \n\t"
>  		"mcr	p15, 0, r0, c1, c0, 1	@ set AUXCR \n\t"
>  		"isb	\n\t"
> -		"dsb	"
> +		"dsb	\n\t"
> +		"ldr	fp, [sp], #4"
>  		: : : "r0","r1","r2","r3","r4","r5","r6","r7",
> -		      "r9","r10","r11","lr","memory");
> +		      "r9","r10","lr","memory");
>  	}
>  
>  	__mcpm_cpu_down(cpu, cluster);
> 
> 
>