Messages in this thread | | | From | Bjorn Helgaas <> | Subject | Re: [PATCH 6/9] resources: add arch hook for preventing allocation in reserved areas | Date | Thu, 16 Dec 2010 15:56:06 -0700 |
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On Thursday, December 16, 2010 03:03:21 pm Linus Torvalds wrote: > On Thu, Dec 16, 2010 at 9:38 AM, Bjorn Helgaas <bjorn.helgaas@hp.com> wrote: > > > > This adds arch_remove_reservations(), which an arch can implement if it > > needs to protect part of the address space from allocation. > > Oh, I just realized - we've had gcc (or maybe "as") bugs when the weak > symbol is in the same compilation unit as the caller, and some part of > the toolchain just ends up short-circuiting it (either gcc inlines it, > or maybe it was that as resolves it early). Making the "weak" part not > work, because it binds strongly. > > It may be that we don't support those gcc versions any more, but I > thought I'd bring the issue up. It's safer to put the weak functions > in some other file if possible.
I'd be glad to repost and do that if necessary. Does anybody know for sure if it is?
I did find these cases where we have a weak symbol definition in the same file as the caller, as well as another version elsewhere, so maybe those toolchains are indeed no longer supported?
arch_disable_smp_support() defined and called in init/main.c (used for "nosmp" arg) also defined in arch/x86/kernel/apic/io_apic.c
smp_setup_processor_id() defined and called in init/main.c also defined in arch/s390/kernel/smp.c also defined in arch/sparc/kernel/smp_64.c
arch_enable_nonboot_cpus_begin() defined and called in kernel/cpu.c also defined in arch/x86/kernel/smpboot.c
arch_irq_work_raise() defined and called in kernel/irq_work.c also defined in arch/sparc/kernel/pcr.c also defined in arch/x86/kernel/irq_work.c
arch_jump_label_text_poke_early() defined and called in kernel/jump_label.c also defined in arch/sparc/kernel/jump_label.c also defined in arch/x86/kernel/jump_label.c
arch_deref_entry_point() defined and called in kernel/kprobes.c also defined in arch/ia64/kernel/kprobes.c also defined in arch/powerpc/kernel/kprobes.c
arch_scale_smt_power() defined and called in kernel/sched_fair.c also defined in arch/x86/kernel/cpu/sched.c
memblock_nid_range() defined and called in mm/memblock.c also defined in arch/sparc/mm/init_64.c
If this toolchain bug is still a problem, I would think all of the above would be defects, so my guess is that we don't have to worry about it any more.
Bjorn
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