On Thursday 17 August 2017 05:31 AM, Bradley Bolen wrote:
> From: Bradley Bolen <bbolen at lexmark.com>
>
> makedumpfile was generating large (> 500MB) vmcore files for an arm64
> board with 2GB of DRAM. It was not excluding any pages because the
> mem_map address was not being converted correctly.
>
> readmem: Can't convert a virtual address(ffffffc07fff6000) to physical
> address.
> readmem: type_addr: 0, addr:ffffffc07fff6000, size:16
> section_mem_map_addr: Can't get a struct mem_section(ffffffc07fff6000).
> mem_map (0)
> mem_map : 0
>
> makedumpfile was not handling 1GB sections in the PGD and was trying to
> drill down to a PTE in which it was trying to dereference invalid
> memory. This patch adds code to check the PGD for a section type and
> handle it instead of treating it as a table entry.
>
> Signed-off-by: Bradley Bolen <bradleybolen at gmail.com>
Reviewed-by: Pratyush Anand <panand at redhat.com>
> ---
> Changes in v2:
> - updated comments
>
> arch/arm64.c | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64.c b/arch/arm64.c
> index 958f57f..25d7a1f 100644
> --- a/arch/arm64.c
> +++ b/arch/arm64.c
> @@ -57,6 +57,8 @@ static unsigned long kimage_voffset;
> #define PGDIR_SHIFT ((PAGESHIFT() - 3) * pgtable_level + 3)
> #define PTRS_PER_PGD (1 << (va_bits - PGDIR_SHIFT))
> #define PUD_SHIFT get_pud_shift_arm64()
> +#define PUD_SIZE (1UL << PUD_SHIFT)
> +#define PUD_MASK (~(PUD_SIZE - 1))
> #define PTRS_PER_PTE (1 << (PAGESHIFT() - 3))
> #define PTRS_PER_PUD PTRS_PER_PTE
> #define PMD_SHIFT ((PAGESHIFT() - 3) * 2 + 3)
> @@ -79,6 +81,10 @@ static unsigned long kimage_voffset;
> #define PMD_TYPE_SECT 1
> #define PMD_TYPE_TABLE 3
>
> +#define PUD_TYPE_MASK 3
> +#define PUD_TYPE_SECT 1
> +#define PUD_TYPE_TABLE 3
> +
> #define pgd_index(vaddr) (((vaddr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
> #define pgd_offset(pgdir, vaddr) ((pgd_t *)(pgdir) + pgd_index(vaddr))
>
> @@ -253,6 +259,13 @@ vaddr_to_paddr_arm64(unsigned long vaddr)
> return NOT_PADDR;
> }
>
> + if ((pud_val(pudv) & PUD_TYPE_MASK) == PUD_TYPE_SECT) {
> + /* 1GB section for Page Table level = 4 and Page Size = 4KB */
> + paddr = (pud_val(pudv) & (PUD_MASK & PMD_SECTION_MASK))
> + + (vaddr & (PUD_SIZE - 1));
> + return paddr;
> + }
> +
> pmda = pmd_offset(puda, &pudv, vaddr);
> if (!readmem(PADDR, (unsigned long long)pmda, &pmdv, sizeof(pmdv))) {
> ERRMSG("Can't read pmd\n");
> @@ -278,7 +291,7 @@ vaddr_to_paddr_arm64(unsigned long vaddr)
> }
> break;
> case PMD_TYPE_SECT:
> - /* 1GB section */
> + /* 512MB section for Page Table level = 3 and Page Size = 64KB*/
> paddr = (pmd_val(pmdv) & (PMD_MASK & PMD_SECTION_MASK))
> + (vaddr & (PMD_SIZE - 1));
> break;
>
--
Regards
Pratyush
