Hi, Johan
Thanks for the fix.
在 2021年03月12日 01:00, [email protected] 写道:
> Date: Thu, 11 Mar 2021 08:54:30 +0000
> From: <[email protected]>
> To: <[email protected]>
> Subject: [Crash-utility] [PATCH] arm64: handle 1GB block
> Message-ID:
>
> <am0p193mb06428b158ee504fe3466b105e3...@am0p193mb0642.eurp193.prod.outlook.com>
>
> Content-Type: text/plain; charset="us-ascii"
>
> With enough continuous physical memory we can have 1GB block. This have
> been seen only in linear mapping region in kernel space. I have only
> verified this for VM_L3_4K.
>
> reference: alloc_init_pud(), use_1G_block() [arch/arm64/mm/mmu.c]
>
For this situation, do you know how to reproduce it easily? Can you share
your steps in detail?
BTW: I did the test, but I didn't enter into the kernel code path because
that condition was not met.
# dmesg|grep -i huge
[ 0.000000] Kernel command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-5.12.0-rc7+
root=/dev/mapper/rhel_gigabyte--r120--20-root ro arm-smmu.disable_bypass=n
initcall_blacklist=gtdt_sbsa_gwdt_init iommu.passthrough=1 crashkernel=512M
hugepagesz=1G hugepages=6 debug_pagealloc=on
rd.lvm.lv=rhel_gigabyte-r120-20/root rd.lvm.lv=rhel_gigabyte-r120-20/swap
[ 2.620634] HugeTLB registered 1.00 GiB page size, pre-allocated 6 pages
Thanks.
Lianbo
> This problem can for instance be seen with vtop command, example:
>
> crash> vtop ffffffd988008000
> VIRTUAL PHYSICAL
> ffffffd988008000 148008000
>
> PAGE DIRECTORY: ffffff9188c6c000
> PGD: ffffff9188c6cb30 => 68000140000711
> PMD: ffffffd980000200 => aa0003e2b9402fe1
> PAGE: 3e2b9400000 (2MB)
>
> PTE PHYSICAL FLAGS
> aa0003e2b9402fe1 3e2b9402000 (VALID|USER|RDONLY|SHARED|AF|NG)
> ---
> arm64.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> diff --git a/arm64.c b/arm64.c
> index 37aed07..4787fa6 100644
> --- a/arm64.c
> +++ b/arm64.c
> @@ -1260,11 +1260,14 @@ arm64_uvtop(struct task_context *tc, ulong uvaddr,
> physaddr_t *paddr, int verbos
> #define PTE_TO_PHYS(pteval) (machdep->max_physmem_bits == 52 ? \
> (((pteval & PTE_ADDR_LOW) | ((pteval & PTE_ADDR_HIGH) << 36))) :
> (pteval & PTE_ADDR_LOW))
>
> +#define PUD_TYPE_MASK 3
> +#define PUD_TYPE_SECT 1
> #define PMD_TYPE_MASK 3
> #define PMD_TYPE_SECT 1
> #define PMD_TYPE_TABLE 2
> #define SECTION_PAGE_MASK_2MB ((long)(~((MEGABYTES(2))-1)))
> #define SECTION_PAGE_MASK_512MB ((long)(~((MEGABYTES(512))-1)))
> +#define SECTION_PAGE_MASK_1GB ((long)(~((GIGABYTES(1))-1)))
>
> static int
> arm64_vtop_2level_64k(ulong pgd, ulong vaddr, physaddr_t *paddr, int verbose)
> @@ -1420,6 +1423,15 @@ arm64_vtop_3level_4k(ulong pgd, ulong vaddr,
> physaddr_t *paddr, int verbose)
> if (!pgd_val)
> goto no_page;
>
> + if ((pgd_val & PUD_TYPE_MASK) == PUD_TYPE_SECT) {
> + ulong sectionbase = (pgd_val & SECTION_PAGE_MASK_1GB) &
> PHYS_MASK;
> + if (verbose) {
> + fprintf(fp, " PAGE: %lx (1GB)\n\n", sectionbase);
> + arm64_translate_pte(pgd_val, 0, 0);
> + }
> + *paddr = sectionbase + (vaddr & ~SECTION_PAGE_MASK_1GB);
> + return TRUE;
> + }
> /*
> * #define __PAGETABLE_PUD_FOLDED
> */
> -- 2.17.1
--
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