[PATCH 4/5] arm64: signal: factor out signal frame record allocation

[Catalin Marinas]

On Thu, Jun 15, 2017 at 03:03:41PM +0100, Dave P Martin wrote:
> This patch factors out the allocator for signal frame optional
> records into a separate function, to ensure consistency and
> facilitate later expansion.
> 
> No overrun checking is currently done, because the allocation is in
> user memory and anyway the kernel never tries to allocate enough
> space in the signal frame yet for an overrun to occur.  This
> behaviour will be refined in future patches.
> 
> The approach taken in this patch to allocation of the terminator
> record is not very clean: this will also be replaced in subsequent
> patches.
> 
> For future extension, a comment is added in sigcontext.h
> documenting the current static allocations in __reserved[].  This
> will be important for determining under what circumstances
> userspace may or may not see an expanded signal frame.
> 
> Signed-off-by: Dave Martin <Dave.Martin at arm.com>

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