[PATCH] arch/arm64: elfcorehdr should be the first allocation

[Will Deacon]

On Mon, Dec 11, 2017 at 11:03:32AM +0530, Prabhakar Kushwaha wrote:
> From: Abhimanyu Saini <abhimanyu.saini at nxp.com>
> 
> elfcorehdr_addr is assigned by kexec-utils and device tree of
> dump kernel is fixed in chosen node with parameter "linux,elfcorehdr".
> So, memory should be first reserved for elfcorehdr,
> otherwise overlaps may happen with other memory allocations
> which were done before the allocation of elcorehdr in the crash kernel

What happens in that case? Do you have a crash log we can include in
the commit message?

> Signed-off-by: Guanhua <guanhua.gao at nxp.com>
> Signed-off-by: Poonam Aggrwal <poonam.aggrwal at nxp.com>
> Signed-off-by: Abhimanyu Saini <abhimanyu.saini at nxp.com>
> ---

Really? How on Earth did you get three people co-developing this patch?

>  arch/arm64/mm/init.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 5960bef0170d..551048cfcfff 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -453,6 +453,10 @@ void __init arm64_memblock_init(void)
>  	 * Register the kernel text, kernel data, initrd, and initial
>  	 * pagetables with memblock.
>  	 */
> +
> +	/* make this the first reservation so that there are no chances of
> +	 * overlap */
> +	reserve_elfcorehdr();
>  	memblock_reserve(__pa_symbol(_text), _end - _text);
>  #ifdef CONFIG_BLK_DEV_INITRD
>  	if (initrd_start) {
> @@ -474,8 +478,6 @@ void __init arm64_memblock_init(void)
>  
>  	reserve_crashkernel();
>  
> -	reserve_elfcorehdr();

Why isn't this also a problem for reserve_crashkernel() or any other
static reservations?

Will