[PATCH 1/5] arm64: signal: split frame link record from sigcontext structure

[Catalin Marinas]

On Thu, Jun 15, 2017 at 03:03:38PM +0100, Dave P Martin wrote:
> In order to be able to increase the amount of the data currently
> written to the __reserved[] array in the signal frame, it is
> necessary to overwrite the locations currently occupied by the
> {fp,lr} frame link record pushed at the top of the signal stack.
> 
> In order for this to work, this patch detaches the frame link
> record from struct rt_sigframe and places it separately at the top
> of the signal stack.  This will allow subsequent patches to insert
> data between it and __reserved[].
> 
> This change relies on the non-ABI status of the placement of the
> frame record with respect to struct sigframe: this status is
> undocumented, but the placement is not declared or described in the
> user headers, and known unwinder implementations (libgcc,
> libunwind, gdb) appear not to rely on it.
> 
> Signed-off-by: Dave Martin <Dave.Martin at arm.com>

I'm fine with this approach:

Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>