On Tue, Mar 31, 2015 at 11:22:29AM -0400, Nicolas Pitre wrote: > On Mon, 30 Mar 2015, Ard Biesheuvel wrote: > > > On 30 March 2015 at 16:13, Michal Marek <mmarek@xxxxxxx> wrote: [...] > > > What you could do is to add a Kconfig option to arch/arm/Kconfig adding > > > -ffunction-sections to the compiler flags. Then allyesconfig would > > > select it and work around the problem in a somewhat elegant way. > > > > > > > Excellent idea! Arnd hasn't chimed in yet, but he is the one doing > > lots and lots of randconfig builds and other test builds, so I will > > wait for him to confirm that this is a useful thing to have. > > I'm using -ffunction-sections as well for the kernel size reduction work > I'm currently doing. The linker script has to be adapted so .text.* is > specified along .text otherwise those functions end up appended at the > end of the binary. Interesting ... do you also mean using --gc-sections at link time? We'd need to avoid pruning needed code that has no explicit caller, and functions that are part of the kernel/module ABI but not used within vmlinux. The GCC docs suggest that -ffunction-sections may impact performance and/or increase code size, but I don't know by how much. Maybe it interferes with inling. Cheers ---Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kbuild" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
