On Tue, Apr 16, 2024 at 06:19:44PM +0200, Nam Cao wrote:
> On 2024-04-16 Björn Töpel wrote:
> > Nam Cao <namcao@xxxxxxxxxxxxx> writes:
> >
> > > Fixed version:
> > >
> > > diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> > > index fa34cf55037b..af4192bc51d0 100644
> > > --- a/arch/riscv/mm/init.c
> > > +++ b/arch/riscv/mm/init.c
> > > @@ -245,6 +245,7 @@ static void __init setup_bootmem(void)
> > > * be done as soon as the kernel mapping base address is determined.
> > > */
> > > if (!IS_ENABLED(CONFIG_64BIT)) {
> > > + memblock_reserve(__pa(-PAGE_SIZE), PAGE_SIZE);
> > > max_mapped_addr = __pa(~(ulong)0);
> > > if (max_mapped_addr == (phys_ram_end - 1))
> > > memblock_set_current_limit(max_mapped_addr - 4096);
> >
> > Nice!
> >
> > Can't we get rid of the if-statement, and max_mapped_address as well?
>
> I don't see why not :D
>
> Best regards,
> Nam
>
> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
> index fa34cf55037b..f600cfee0aef 100644
> --- a/arch/riscv/mm/init.c
> +++ b/arch/riscv/mm/init.c
> @@ -197,7 +197,6 @@ early_param("mem", early_mem);
> static void __init setup_bootmem(void)
> {
> phys_addr_t vmlinux_end = __pa_symbol(&_end);
> - phys_addr_t max_mapped_addr;
> phys_addr_t phys_ram_end, vmlinux_start;
>
> if (IS_ENABLED(CONFIG_XIP_KERNEL))
> @@ -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.
> min_low_pfn = PFN_UP(phys_ram_base);
> max_low_pfn = max_pfn = PFN_DOWN(phys_ram_end);
>
--
Sincerely yours,
Mike.
