From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Ellerman Date: Tue, 19 Sep 2017 10:22:37 +0000 Subject: Re: [PATCH 3/5] powerpc64: Add .opd based function descriptor dereference Message-Id: <87shfjkmxe.fsf@concordia.ellerman.id.au> List-Id: References: <20170916035347.19705-1-sergey.senozhatsky@gmail.com> <20170916035347.19705-4-sergey.senozhatsky@gmail.com> <20170916094345.d332z3odceqiyrll@naverao1-tp.localdomain> In-Reply-To: <20170916094345.d332z3odceqiyrll@naverao1-tp.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "Naveen N. Rao" , Sergey Senozhatsky Cc: Tony Luck , Fenghua Yu , Benjamin Herrenschmidt , Paul Mackerras , "James E . J . Bottomley" , Helge Deller , Petr Mladek , linux-ia64@vger.kernel.org, linux-parisc@vger.kernel.org, Alexei Starovoitov , Steven Rostedt , linux-kernel@vger.kernel.org, Jessica Yu , Andrew Morton , linuxppc-dev@lists.ozlabs.org, Nicholas Piggin "Naveen N. Rao" writes: > On 2017/09/16 12:53PM, Sergey Senozhatsky wrote: >> We are moving towards separate kernel and module function descriptor >> dereference callbacks. This patch enables it for powerpc64. >> >> For pointers that belong to the kernel >> - Added __start_opd and __end_opd pointers, to track the kernel >> .opd section address range; >> >> - Added dereference_kernel_function_descriptor(). Now we >> will dereference only function pointers that are within >> [__start_opd, __end_opd]; >> >> For pointers that belong to a module >> - Added dereference_module_function_descriptor() to handle module >> function descriptor dereference. Now we will dereference only >> pointers that are within [module->opd.start, module->opd.end]. > > Would it be simpler to just use kernel_text_address() and dereference > everything else? See commit 83e840c770f2c5 ("powerpc64/elfv1: Only > dereference function descriptor for non-text symbols") for a related > patch. Yeah that would be a lot simpler and probably work perfectly well. cheers