Re: linux-next: manual merge of the akpm-current tree with the risc-v tree

Atish Patra
2020-10-07T04:48:10Z

On Tue, 2020-10-06 at 21:32 -0700, Palmer Dabbelt wrote:
> On Tue, 06 Oct 2020 03:39:06 PDT (-0700), Stephen Rothwell wrote:
> > Hi all,
> >
> > Today's linux-next merge of the akpm-current tree got a conflict
> > in:
> >
> > arch/riscv/mm/init.c
> >
> > between commit:
> >
> > c29c38fa2a8b ("RISC-V: Remove any memblock representing unusable
> > memory area")
> >
> > from the risc-v tree and commits:
> >
> > 3520eeb79142 ("arch, drivers: replace for_each_membock() with
> > for_each_mem_range()")
> >
> > from the akpm-current tree.
> >
> > I fixed it up (see below) and can carry the fix as necessary. This
> > is now fixed as far as linux-next is concerned, but any non trivial
> > conflicts should be mentioned to your upstream maintainer when your
> > tree
> > is submitted for merging. You may also want to consider
> > cooperating
> > with the maintainer of the conflicting tree to minimise any
> > particularly
> > complex conflicts.
> >
> > It also looks like there is a bug in that risc-v tree patch:
> > mem_start
> > is used uninitialised in setup_bootmem().
> > --
> > Cheers,
> > Stephen Rothwell
> >
> > diff --cc arch/riscv/mm/init.c
> > index 812a48c91a95,bc72bb6b5fe0..000000000000
> > --- a/arch/riscv/mm/init.c
> > +++ b/arch/riscv/mm/init.c
> > @@@ -152,20 -141,25 +152,20 @@@ disable
> > }
> > #endif /* CONFIG_BLK_DEV_INITRD */
> >
> > -static phys_addr_t dtb_early_pa __initdata;
> > -
> > void __init setup_bootmem(void)
> > {
> > - struct memblock_region *reg;
> > - phys_addr_t mem_start, end = 0;
> > - phys_addr_t mem_size = 0;
> > - phys_addr_t total_mem = 0;
> > + phys_addr_t mem_start, start, end = 0;
> > phys_addr_t vmlinux_end = __pa_symbol(&_end);
> > phys_addr_t vmlinux_start = __pa_symbol(&_start);
> > + u64 i;
> >
> > /* Find the memory region containing the kernel */
> > - for_each_memblock(memory, reg) {
> > - end = reg->base + reg->size;
> > + for_each_mem_range(i, &start, &end) {
> > + phys_addr_t size = end - start;
> > - if (!total_mem)
> > + if (!mem_start)
> > - mem_start = reg->base;
> > - if (reg->base <= vmlinux_start && vmlinux_end <= end)
> > - BUG_ON(reg->size == 0);
> > + mem_start = start;
> > + if (start <= vmlinux_start && vmlinux_end <= end)
> > + BUG_ON(size == 0);
> > - total_mem = total_mem + size;
> > }
> >
> > /*
> > @@@ -542,18 -455,11 +533,18 @@@ static void __init
> > setup_vm_final(void
> > {
> > uintptr_t va, map_size;
> > phys_addr_t pa, start, end;
> > - struct memblock_region *reg;
> > + u64 i;
> >
> > - /* Set mmu_enabled flag */
> > - mmu_enabled = true;
> > -
> > + /**
> > + * MMU is enabled at this point. But page table setup is not
> > complete yet.
> > + * fixmap page table alloc functions should be used at this
> > point
> > + */
> > + pt_ops.alloc_pte = alloc_pte_fixmap;
> > + pt_ops.get_pte_virt = get_pte_virt_fixmap;
> > +#ifndef __PAGETABLE_PMD_FOLDED
> > + pt_ops.alloc_pmd = alloc_pmd_fixmap;
> > + pt_ops.get_pmd_virt = get_pmd_virt_fixmap;
> > +#endif
> > /* Setup swapper PGD for fixmap */
> > create_pgd_mapping(swapper_pg_dir, FIXADDR_START,
> > __pa_symbol(fixmap_pgd_next),
>
> Thanks for pointing this out. Given that this is the tip of my for-
> next I'm
> just going to drop it, we'll sort out the bug and the conflict.

Thanks. I will rebase on top of next after fixing the bug and resend.

--
Regards,
Atish