On Tue, Apr 16, 2024 at 07:31:54PM +0300, Mike Rapoport wrote:
> > @@ -238,17 +237,9 @@ static void __init setup_bootmem(void)
> > /*
> > * memblock allocator is not aware of the fact that last 4K bytes of
> > * the addressable memory can not be mapped because of IS_ERR_VALUE
> > - * macro. Make sure that last 4k bytes are not usable by memblock
> > - * if end of dram is equal to maximum addressable memory. For 64-bit
> > - * kernel, this problem can't happen here as the end of the virtual
> > - * address space is occupied by the kernel mapping then this check must
> > - * be done as soon as the kernel mapping base address is determined.
> > + * macro. Make sure that last 4k bytes are not usable by memblock.
> > */
>
> It's not only memblock, but buddy as well, so maybe
>
> /*
> * The last 4K bytes of the addressable memory can not be used
> * because of IS_ERR_VALUE macro. Make sure that last 4K bytes are
> * not usable by kernel memory allocators.
> */
>
> > - if (!IS_ENABLED(CONFIG_64BIT)) {
> > - max_mapped_addr = __pa(~(ulong)0);
> > - if (max_mapped_addr == (phys_ram_end - 1))
> > - memblock_set_current_limit(max_mapped_addr - 4096);
> > - }
> > + memblock_reserve(__pa(-PAGE_SIZE), PAGE_SIZE);
>
> Ack.
Can this go to generic code instead of letting architecture maintainers
fall over it?
