ARM: mm: Could I change module space size or place modules in vmalloc area?
From: Gioh Kim <hidden>
Date: 2014-03-12 06:38:44
Also in:
linux-mm
I am sorry to read your mail so late. My module had been a proprietary driver so that I requested to strip it and got small size driver. Thank you for attention.
-----Original Message----- From: Arnd Bergmann [mailto:arnd at arndb.de] Sent: Friday, January 03, 2014 10:24 PM To: linux-arm-kernel at lists.infradead.org Cc: Russell King - ARM Linux; HyoJun Im; linux-mm at kvack.org; Gioh Kim Subject: Re: ARM: mm: Could I change module space size or place modules in vmalloc area? On Friday 03 January 2014, Russell King - ARM Linux wrote:quoted
On Fri, Jan 03, 2014 at 01:10:09PM +0100, Arnd Bergmann wrote:quoted
Aside from the good comments that Russell made, I would remark that the fact that you need multiple megabytes worth of modules indicates that you are doing something wrong. Can you point to a git tree containing those modules?From the comments which have been made, one point that seems to have been identified is that if this module is first stripped and then loaded, it can load, but if it's unstripped, it's too big. This sounds suboptimal to me - the debug info shouldn't be loaded into thekernel. Reading the layout_and_allocate() function, that is probably the intention already, and if something goes wrong there on ARM, it could be fixed up in an arch specific module_frob_arch_sections() function.quoted
However, I guess there's bad interactions with module signing if you don't do this and the module was signed with the debug info present, so I don't think there's a good solution for this.My point was another anyway: I can't think of any good reason why you would end up with this many modules on any sane system. The only cases I've seen so far are - modules written in C++, with libstdc++ linked into the module - a closed-source platform port hidden in a loadable module that contains all the device drivers and subsystems while ignoring the infrastructure we have in the kernel, and the possible legal implications. - a bug in the module using large arrays that should just be dynamically allocated. - device firmware statically linked into the module rather than loaded using request_firmware. In each of these cases, the real answer is to fix the code they are trying to load to do things in a more common way, especially if the intention is to eventually merge the code upstream. It is of course possible that they are indeed trying something valid, that's why I asked to see the source code. Arnd