[PATCH] ARM: bootm: recalculate decompression space

[Alexander Kurz]

Hi Stefan,
FYI, I just got a compiler warning obviously related to your patch
On Fri Jul 1 07:48:39 PDT 2016, Stefan Müller-Klieser wrote:

> diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
> index 803aa94..be1259b 100644
> --- a/arch/arm/lib/bootm.c
> +++ b/arch/arm/lib/bootm.c
> @@ -81,10 +81,15 @@ static int get_kernel_addresses(size_t image_size,
>  		return ret;
>  
>  	/*
> -	 * We don't know the exact decompressed size so just use a 
> conservative
> -	 * default of 4 times the size of the compressed image.
> +	 * The kernel documentation "Documentation/arm/Booting" advises
> +	 * to place the compressed image outside of the lowest 32 MiB to
> +	 * avoid relocation. We should do this if we have at least 64 MiB
> +	 * of ram. If we have less space, we assume a maximum
> +	 * compression factor of 5.
>  	 */
> -	image_decomp_size = PAGE_ALIGN(image_size * 4);
> +	image_decomp_size = PAGE_ALIGN(image_size * 5);
> +	if (mem_size >= SZ_64M)
> +		image_decomp_size = max(image_decomp_size, SZ_32M);
>  
>  	/*
>  	 * By default put oftree/initrd close behind compressed kernel 
> image to

this one:
>   CC      arch/arm/lib/bootm.o
> In file included from include/common.h:30:0,
>                  from arch/arm/lib/bootm.c:2:
> arch/arm/lib/bootm.c: In function 'get_kernel_addresses':
> include/linux/kernel.h:110:17: warning: comparison of distinct pointer 
> types lacks a cast
>   (void) (&_max1 == &_max2);  \
>                 ^
> arch/arm/lib/bootm.c:92:23: note: in expansion of macro 'max'
>    image_decomp_size = max(image_decomp_size, SZ_32M);
>                        ^

I am using
$ gcc --version
arm-arm1136jfs-linux-gnueabi-gcc (crosstool-NG crosstool-ng-1.22.0) 5.2.0

Regards, Alexander