From mboxrd@z Thu Jan 1 00:00:00 1970 From: catalin.marinas@arm.com (Catalin Marinas) Date: Thu, 15 Jun 2017 17:37:47 +0100 Subject: [PATCH 1/5] arm64: signal: split frame link record from sigcontext structure In-Reply-To: <1497535442-11586-2-git-send-email-Dave.Martin@arm.com> References: <1497535442-11586-1-git-send-email-Dave.Martin@arm.com> <1497535442-11586-2-git-send-email-Dave.Martin@arm.com> Message-ID: <20170615163747.GA17424@e104818-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 I'm fine with this approach: Reviewed-by: Catalin Marinas