On Tue, Nov 03, 2020 at 04:25:15PM +0000, Alexandru Elisei wrote:
> Hi,
>
> On 11/3/20 4:10 PM, Andrew Jones wrote:
> > On Tue, Nov 03, 2020 at 03:49:32PM +0000, Nikos Nikoleris wrote:
> >>>> diff --git a/lib/arm64/asm/page.h b/lib/arm64/asm/page.h
> >>>> index 46af552..2a06207 100644
> >>>> --- a/lib/arm64/asm/page.h
> >>>> +++ b/lib/arm64/asm/page.h
> >>>> @@ -10,38 +10,51 @@
> >>>> * This work is licensed under the terms of the GNU GPL, version 2.
> >>>> */
> >>>> +#include <config.h>
> >>>> #include <linux/const.h>
> >>>> -#define PGTABLE_LEVELS 2
> >>>> #define VA_BITS 42
> >>> Let's bump VA_BITS to 48 while we're at it.
> > I tried my suggestion to go to 48 VA bits, but it seems to break
> > things for 64K pages.
>
> I believe that is because we end up with PGTABLE_LEVELS=3 and in
> mmu_set_ranges_sect() we try to install a block mapping at the PUD level, which is
> forbidden by the architecture.
>
> I think the easiest fix for that is to always try to install block mapping at the
> pmd level. The diff below fixed all errors (with 16k and 64k pages):
>
> diff --git a/lib/arm/mmu.c b/lib/arm/mmu.c
> index 6d1c75b00eaa..d33948a8a06a 100644
> --- a/lib/arm/mmu.c
> +++ b/lib/arm/mmu.c
> @@ -134,20 +134,22 @@ void mmu_set_range_sect(pgd_t *pgtable, uintptr_t virt_offset,
> phys_addr_t phys_start, phys_addr_t phys_end,
> pgprot_t prot)
> {
> - phys_addr_t paddr = phys_start & PUD_MASK;
> - uintptr_t vaddr = virt_offset & PUD_MASK;
> + phys_addr_t paddr = phys_start & PMD_MASK;
> + uintptr_t vaddr = virt_offset & PMD_MASK;
> uintptr_t virt_end = phys_end - paddr + vaddr;
> pgd_t *pgd;
> pud_t *pud;
> - pud_t entry;
> + pmd_t *pmd;
> + pmd_t entry;
>
> - for (; vaddr < virt_end; vaddr += PUD_SIZE, paddr += PUD_SIZE) {
> - pud_val(entry) = paddr;
> - pud_val(entry) |= PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S;
> - pud_val(entry) |= pgprot_val(prot);
> + for (; vaddr < virt_end; vaddr += PMD_SIZE, paddr += PMD_SIZE) {
> + pmd_val(entry) = paddr;
> + pmd_val(entry) |= PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S;
> + pmd_val(entry) |= pgprot_val(prot);
> pgd = pgd_offset(pgtable, vaddr);
> pud = pud_alloc(pgd, vaddr);
> - WRITE_ONCE(*pud, entry);
> + pmd = pmd_alloc(pud, vaddr);
> + WRITE_ONCE(*pmd, entry);
> flush_tlb_page(vaddr);
Nice work! This resolves my issue as well. And, I can run with 16K pages
on my thunderx now too.
> }
> }
> diff --git a/lib/arm64/asm/page.h b/lib/arm64/asm/page.h
> index 2a06207444aa..f649f56bf16f 100644
> --- a/lib/arm64/asm/page.h
> +++ b/lib/arm64/asm/page.h
> @@ -13,7 +13,7 @@
> #include <config.h>
> #include <linux/const.h>
>
> -#define VA_BITS 42
> +#define VA_BITS 46
Let's use 48.
>
> #define PAGE_SIZE CONFIG_PAGE_SIZE
> #if PAGE_SIZE == 65536
>
> Thanks,
>
> Alex
>
Thanks,
drew
