Before the kernel v5.7, the VMEMMAP_END does not exit. In the patch "e397e1b arm64: update the modules/vmalloc/vmemmap ranges" it sets -1(0xffffffffffffffffUL) for vmemmap_end for the kernel versions before v5.7. But from the arch/arm64/mm/dump.c (before kernel v5.7): ...................................... { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" } ...................................... we can know that the vmemmap_end should always be: vmemmap_end = vmemmap_vaddr + vmemmap_size; This patch fixes this issue. Signed-off-by: Huang Shijie <shijie(a)os.amperecomputing.com&gt; --- arm64.c | 26 +++++++++++--------------- 1 file changed, 11 insertions(+), 15 deletions(-) diff --git a/arm64.c b/arm64.c index d81c2b9..f75599e 100644 --- a/arm64.c +++ b/arm64.c @@ -285,11 +285,7 @@ arm64_init(int when) ms->vmalloc_start_addr = r->vmalloc_start_addr; ms->vmalloc_end = r->vmalloc_end - 1; ms->vmemmap_vaddr = r->vmemmap_vaddr; - if (THIS_KERNEL_VERSION >= LINUX(5, 7, 0)) - ms->vmemmap_end = r->vmemmap_end - 1; - else - ms->vmemmap_end = -1; - + ms->vmemmap_end = r->vmemmap_end - 1; } else if (ms->VA_BITS_ACTUAL) { ms->modules_vaddr = (st->_stext_vmlinux & TEXT_OFFSET_MASK) - ARM64_MODULES_VSIZE; ms->modules_end = ms->modules_vaddr + ARM64_MODULES_VSIZE -1; @@ -739,15 +735,15 @@ static struct kernel_range *arm64_get_range_v5_4(struct machine_specific *ms) vmemmap_size = (_PAGE_END(v) - PAGE_OFFSET) >> vmem_shift; r->vmemmap_vaddr = (-vmemmap_size - SZ_2M); - if (THIS_KERNEL_VERSION >= LINUX(5, 7, 0)) { - /* - * In the v5.7, the patch: "bbd6ec605c arm64/mm: Enable memory hot remove" - * adds the VMEMMAP_END. - */ - r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size; - } else { - r->vmemmap_end = 0xffffffffffffffffUL; - } + /* + * In the v5.7, the patch: "bbd6ec605c arm64/mm: Enable memory hot remove" + * adds the VMEMMAP_END. + * + * But before the VMEMMAP_END was added to kernel, we can also see + * the following in arch/arm64/mm/dump.c: + * { VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" }, + */ + r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size; /* Get the VMALLOC_START ~ VMALLOC_END */ PUD_SIZE = arm64_get_pud_size(); @@ -795,7 +791,7 @@ static struct kernel_range *arm64_get_range_v5_0(struct machine_specific *ms) vmemmap_size = (1UL << (v - machdep->pageshift - 1 + arm64_get_struct_page_max_shift(ms))); r->vmemmap_vaddr = page_offset - vmemmap_size; - r->vmemmap_end = 0xffffffffffffffffUL; /* this kernel does not have VMEMMAP_END */ + r->vmemmap_end = r->vmemmap_vaddr + vmemmap_size; /* See the arch/arm64/mm/dump.c */ /* Get the VMALLOC_START ~ VMALLOC_END */ PUD_SIZE = arm64_get_pud_size(); -- 2.30.2