Messages in this thread | | | Date | Wed, 4 Aug 2010 13:56:58 +0200 | From | Sam Ravnborg <> | Subject | Re: missing .data.shared_align placement in vmlinux |
| |
On Fri, May 21, 2010 at 04:58:53PM -0400, Mike Frysinger wrote: > am i missing something or does the .data.shared_align section lack > definition in vmlinux.lds.h and all arch vmlinux.lds.S files ? > > with the recent change "net: remove time limit in process_backlog()", > the softnet_data variable changed from "DEFINE_PER_CPU()" to > "DEFINE_PER_CPU_ALIGNED()" which moved it from the .data section to > the .data.shared_align section. i'm not saying this patch is wrong, > just that is what caused me to notice this larger problem. no one > else in the kernel is using this aligned macro variant, so i imagine > that's why no one has noticed yet. > > since .data.shared_align isnt declared in any vmlinux files that i can > see, the linker just places it last. this "just works" for most > people, but when building a ROM kernel on Blackfin systems, it causes > section overlap errors: > bfin-uclinux-ld.real: section .init.data [00000000202e06b8 -> > 00000000202e48b7] overlaps section .data.shared_aligned > [00000000202e06b8 -> 00000000202e0723] > i imagine other arches which support the ROM config option and thus do > funky placement would see similar issues ... > > on x86, it is stuck in a dedicated section: > [ 8] .data PROGBITS ffffffff810ec000 2ec000 > 0303a8 00 WA 0 0 4096 > [ 9] .data.shared_alig PROGBITS ffffffff8111c3c0 31c3c0 > 0000c8 00 WA 0 0 64 > > the ifdef forest in asm-generic/percpu.h is beyond a quick glance & > fix, so i leave it up to someone else ;)
as there any resolution on this? I briefly looked at it some time ago. And it looks like a plain oversight.
But I was also a bit lost in the forest of ifdef land...
Sam
| |