[Crash-utility] [PATCH v2] arm64: handle 1GB block for VM_L4_4K

[Rongwei Wang]

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 at nec.com>
Signed-off-by: Rongwei Wang <rongwei.wang at linux.alibaba.com>
---
 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