Messages in this thread | | | From | Mike Frysinger <> | Date | Fri, 21 May 2010 16:58:53 -0400 | Subject | missing .data.shared_align placement in vmlinux |
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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 ;) -mike
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