Michael Ellerman <m...@ellerman.id.au> writes: > Andrew Morton <a...@linux-foundation.org> writes: >> On Mon, 6 Aug 2018 12:39:21 +0200 Geert Uytterhoeven <ge...@linux-m68k.org> >> wrote: >> >>> CC Dan, Michael, AKPM, powerpc >>> >>> On Mon, Apr 16, 2018 at 3:10 PM Geert Uytterhoeven <ge...@linux-m68k.org> >>> wrote: >>> > Below is the list of build error/warning regressions/improvements in >>> > v4.17-rc1[1] compared to v4.16[2]. >>> >>> I'd like to point your attention to: >>> >>> > + warning: vmlinux.o(.text+0x376518): Section mismatch in reference >>> > from the function .devm_memremap_pages() to the function >>> > .meminit.text:.arch_add_memory(): => N/A >>> > + warning: vmlinux.o(.text+0x376d64): Section mismatch in reference >>> > from the function .devm_memremap_pages_release() to the function >>> > .meminit.text:.arch_remove_memory(): => N/A >> >> hm. Dan isn't around at present so we're on our own with this one. >> >> x86 doesn't put arch_add_memory and arch_remove_memory into __meminit. >> x86 does >> >> #ifdef CONFIG_MEMORY_HOTPLUG >> int arch_add_memory(int nid, u64 start, u64 size, struct vmem_altmap *altmap, >> bool want_memblock) >> { >> ... >> >> >> So I guess powerpc should do that as well? > > But we only recently added it to fix a section mismatch warning: > > WARNING: vmlinux.o(.text+0x6da88): Section mismatch in reference from the > function .arch_add_memory() to the function > .meminit.text:.create_section_mapping() > The function .arch_add_memory() references > the function __meminit .create_section_mapping(). > This is often because .arch_add_memory lacks a __meminit > annotation or the annotation of .create_section_mapping is wrong. > > > I think the problem is that the section mismatch logic isn't able to > cope with __meminit's changing semantics. > > When CONFIG_MEMORY_HOTPLUG=y references from .text to .meminit.text > should be allowed, because they're just folded in together in the linker > script. > > When CONFIG_MEMORY_HOTPLUG=n references from .text to .meminit.text > should NOT be allowed, because .meminit.text becomes .init.text and will > be freed. > > I don't see anything in the section mismatch logic to cope with that > difference. > > It looks like __meminit is saving us about 1K on powerpc, so I'm > strongly inclined to just remove it entirely from arch/powerpc.
Gah that doesn't work. Our arch routines call things in mm/ that are __meminit, so we have to mark our code __meminit too, otherwise we get a section mismatch warning. cheers