Hi, thanks for the patch. > -----Original Message----- > Subject: [Crash-utility] [PATCH RFC] arm64: fix vtop command when handling PUD mapping I think probably this issue will appear not only with vtop command, so I would suggest "arm64: handle 1GB block for VM_L4_4K" like the patch fixing a similar issue for VM_L3_4K: commit c25234e3573a7a0744430e922146ee362 Author: Johan Erlandsson <johan.erlandsson(a)sony.com&gt; Date: Thu Mar 11 08:54:30 2021 +0000 arm64: handle 1GB block for VM_L3_4K

Otherwise, the patch looks good to me. With the change above: Acked-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; Thanks, Kazu > When arm64 is configed with PAGE_SIZE=4k and 4 level > translation, the pagetable of all pages may be created > with block mapping or contiguous mapping as much as > possible, likes disable CONFIG_RODATA_FULL_DEFAULT_ENABLED. > But now, vtop command can not handle pud mapping well, and > just shows a seek error: > > crash> vtop ffff00184a800000 > VIRTUAL PHYSICAL > ffff00184a800000 188a800000 > > PAGE DIRECTORY: ffff8000110aa000 > PGD: ffff8000110aa000 => 203fff9003 > PUD: ffff001fffff9308 => 68001880000705 > PMD: ffff0018400002a0 => ffff8000103b4fd0 > vtop: seek error: kernel virtual address: ffff7fffd03b4000 type: "page table" > > This patch fixes it, and shows as following: > > crash> vtop ffff00184a800000 > VIRTUAL PHYSICAL > ffff00184a800000 188a800000 > > PAGE DIRECTORY: ffff8000110aa000 > PGD: ffff8000110aa000 => 203fff9003 > PUD: ffff001fffff9308 => 68001880000705 > PAGE: 1880000000 (1GB) > > PTE PHYSICAL FLAGS > 68001880000705 1880000000 (VALID|SHARED|AF|PXN|UXN) > > PAGE PHYSICAL MAPPING INDEX CNT FLAGS > fffffe00610a0000 188a800000 0 0 0 77fffe0000000000 > > Signed-off-by: Rongwei Wang <rongwei.wang(a)linux.alibaba.com&gt; > --- > arm64.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/arm64.c b/arm64.c > index 2177c52..65f6cdf 100644 > --- a/arm64.c > +++ b/arm64.c > @@ -1999,6 +1999,16 @@ arm64_vtop_4level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) > if (!pud_val) > goto no_page; > > + if ((pud_val & PUD_TYPE_MASK) == PUD_TYPE_SECT) { > + ulong sectionbase = (pud_val & SECTION_PAGE_MASK_1GB) & PHYS_MASK; > + if (verbose) { > + fprintf(fp, " PAGE: %lx (1GB)\n\n", sectionbase); > + arm64_translate_pte(pud_val, 0, 0); > + } > + *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_1GB); > + return TRUE; > + } > + > pmd_base = (ulong *)PTOV(pud_val & PHYS_MASK & (s32)machdep->pagemask); > FILL_PMD(pmd_base, KVADDR, PTRS_PER_PMD_L4_4K * sizeof(ulong)); > pmd_ptr = pmd_base + (((vaddr) >> PMD_SHIFT_L4_4K) & (PTRS_PER_PMD_L4_4K - 1)); > -- > 2.27.0 > > -- > Crash-utility mailing list > Crash-utility(a)redhat.com > https://listman.redhat.com/mailman/listinfo/crash-utility > Contribution Guidelines: https://github.com/crash-utility/crash/wiki

When arm64 is configured with PAGE_SIZE=4k and 4 level translation, the pagetable of all pages may be created with block mapping or contiguous mapping as much as possible, likes disable CONFIG_RODATA_FULL_DEFAULT_ENABLED. But now, vtop command can not handle 1GB block (PUD mapping) well, and just shows a seek error: crash> vtop ffff00184a800000 VIRTUAL PHYSICAL ffff00184a800000 188a800000 PAGE DIRECTORY: ffff8000110aa000 PGD: ffff8000110aa000 => 203fff9003 PUD: ffff001fffff9308 => 68001880000705 PMD: ffff0018400002a0 => ffff8000103b4fd0 vtop: seek error: kernel virtual address: ffff7fffd03b4000 type: "page table" This patch fixes it, and shows as following: crash> vtop ffff00184a800000 VIRTUAL PHYSICAL ffff00184a800000 188a800000 PAGE DIRECTORY: ffff8000110aa000 PGD: ffff8000110aa000 => 203fff9003 PUD: ffff001fffff9308 => 68001880000705 PAGE: 1880000000 (1GB) PTE PHYSICAL FLAGS 68001880000705 1880000000 (VALID|SHARED|AF|PXN|UXN) PAGE PHYSICAL MAPPING INDEX CNT FLAGS fffffe00610a0000 188a800000 0 0 0 77fffe0000000000 Acked-by: Kazuhito Hagio <k-hagio-ab(a)nec.com&gt; Signed-off-by: Rongwei Wang <rongwei.wang(a)linux.alibaba.com&gt; --- arm64.c | 10 ++++++++++ 1 file changed, 10 insertions(+) diff --git a/arm64.c b/arm64.c index 2177c52..65f6cdf 100644 --- a/arm64.c +++ b/arm64.c @@ -1999,6 +1999,16 @@ arm64_vtop_4level_4k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose) if (!pud_val) goto no_page; + if ((pud_val & PUD_TYPE_MASK) == PUD_TYPE_SECT) { + ulong sectionbase = (pud_val & SECTION_PAGE_MASK_1GB) & PHYS_MASK; + if (verbose) { + fprintf(fp, " PAGE: %lx (1GB)\n\n", sectionbase); + arm64_translate_pte(pud_val, 0, 0); + } + *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_1GB); + return TRUE; + } + pmd_base = (ulong *)PTOV(pud_val & PHYS_MASK & (s32)machdep->pagemask); FILL_PMD(pmd_base, KVADDR, PTRS_PER_PMD_L4_4K * sizeof(ulong)); pmd_ptr = pmd_base + (((vaddr) >> PMD_SHIFT_L4_4K) & (PTRS_PER_PMD_L4_4K - 1));