linux-kernel - Re: [PATCH v6 13/21] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32

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Message-ID: <7056596.KRbB42JIuZ@wuerfel>
Date:	Fri, 08 Jan 2016 10:01:55 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Yury Norov <ynorov@...iumnetworks.com>
Cc:	catalin.marinas@....com, linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org, pinskia@...il.com,
	Prasun.Kapoor@...iumnetworks.com, schwab@...e.de,
	Nathan_Lynch@...tor.com, agraf@...e.de, klimov.linux@...il.com,
	broonie@...nel.org, jan.dakinevich@...il.com,
	ddaney.cavm@...il.com, bamvor.zhangjian@...wei.com,
	philipp.tomsich@...obroma-systems.com, joseph@...esourcery.com,
	christoph.muellner@...obroma-systems.com
Subject: Re: [PATCH v6 13/21] arm64: ptrace: handle ptrace_request differently for aarch32 and ilp32

On Friday 08 January 2016 02:34:31 Yury Norov wrote:
> +long compat_arch_ptrace(struct task_struct *child, compat_long_t request,
> +                       compat_ulong_t caddr, compat_ulong_t cdata)
> +{
> +       if (is_a32_compat_task())
> +               return compat_a32_ptrace(child, request, caddr, cdata);
> +
> +       return compat_ptrace_request(child, request, caddr, cdata);
> +}
> +

Looking at this again, I think we can avoid this runtime check
if we duplicate the compat_sys_ptrace function and make a special one
for a32 that is copied from the regular handler and but calls
compat_a32_ptrace directly. Or maybe make a separate handler for
arm64-ilp32 if that is smaller.

	Arnd