On Wed, Sep 27, 2023 at 06:32:44AM +0000, HAGIO KAZUHITO(萩尾 一仁) wrote: > On 2023/09/14 18:22, Aditya Gupta wrote: > > Currently 'makedumpfile' fails to collect vmcore on upstream kernel, > > with the errors: > > > > readpage_elf: Attempt to read non-existent page at 0x4000000000000000. > > readmem: type_addr: 0, addr:0, size:8 > > get_vmemmap_list_info: Can't get vmemmap region addresses > > get_machdep_info_ppc64: Can't get vmemmap list info. > > > > This occurs since makedumpfile depends on 'vmemmap_list' for translating > > vmemmap addresses. But with below commit in Linux, vmemmap_list can be > > empty, in case of Radix MMU on PowerPC64 > > > > 368a0590d954: (powerpc/book3s64/vmemmap: switch radix to use a > > different vmemmap handling function) > > > > In case vmemmap_list is empty, then it's head is NULL, which causes > > makedumpfile to fail with above error. > > > > Since with above commit, 'vmemmap_list' is not populated (when MMU is > > Radix MMU), kernel populates corresponding page table entries in kernel > > page table. Hence, instead of depending on 'vmemmap_list' for address > > translation for vmemmap addresses, do a kernel pagetable walk. > > > > And since the pte can also be introduced at higher levels in the page > > table, such as at PMD level, add hugepage support, by checking for > > PAGE_PTE flag > > > > Reported-by: Sachin Sant <sachinp@xxxxxxxxxxxxx> > > Signed-off-by: Aditya Gupta <adityag@xxxxxxxxxxxxx> > > Thank you for the patch, applied. > > https://github.com/makedumpfile/makedumpfile/commit/a34f017965583e89c4cb0b00117c200a6c191e54 Thanks for the update. > > Sorry for the delay, exceptionally busy this month.. No issues :) Thanks, - Aditya Gupta > > Thanks, > Kazu > > > --- > > arch/ppc64.c | 111 ++++++++++++++++++++++++++++++++++--------------- > > makedumpfile.h | 6 +++ > > 2 files changed, 84 insertions(+), 33 deletions(-) > > > > diff --git a/arch/ppc64.c b/arch/ppc64.c > > index 5e70acb51aba..9456b8b570c5 100644 > > --- a/arch/ppc64.c > > +++ b/arch/ppc64.c > > @@ -196,6 +196,10 @@ ppc64_vmemmap_init(void) > > int psize, shift; > > ulong head; > > > > + /* initialise vmemmap_list in case SYMBOL(vmemmap_list) is not found */ > > + info->vmemmap_list = NULL; > > + info->vmemmap_cnt = 0; > > + > > if ((SYMBOL(vmemmap_list) == NOT_FOUND_SYMBOL) > > || (SYMBOL(mmu_psize_defs) == NOT_FOUND_SYMBOL) > > || (SYMBOL(mmu_vmemmap_psize) == NOT_FOUND_SYMBOL) > > @@ -216,15 +220,24 @@ ppc64_vmemmap_init(void) > > return FALSE; > > info->vmemmap_psize = 1 << shift; > > > > - if (!readmem(VADDR, SYMBOL(vmemmap_list), &head, sizeof(unsigned long))) > > - return FALSE; > > - > > /* > > - * Get vmemmap list count and populate vmemmap regions info > > - */ > > - info->vmemmap_cnt = get_vmemmap_list_info(head); > > - if (info->vmemmap_cnt == 0) > > - return FALSE; > > + * vmemmap_list symbol can be missing or set to 0 in the kernel. > > + * This would imply vmemmap region is mapped in the kernel pagetable. > > + * > > + * So, read vmemmap_list anyway, and use 'vmemmap_list' if it's not empty > > + * (head != NULL), or we will do a kernel pagetable walk for vmemmap address > > + * translation later > > + **/ > > + readmem(VADDR, SYMBOL(vmemmap_list), &head, sizeof(unsigned long)); > > + > > + if (head) { > > + /* > > + * Get vmemmap list count and populate vmemmap regions info > > + */ > > + info->vmemmap_cnt = get_vmemmap_list_info(head); > > + if (info->vmemmap_cnt == 0) > > + return FALSE; > > + } > > > > info->flag_vmemmap = TRUE; > > return TRUE; > > @@ -347,29 +360,6 @@ ppc64_vmalloc_init(void) > > return TRUE; > > } > > > > -/* > > - * If the vmemmap address translation information is stored in the kernel, > > - * make the translation. > > - */ > > -static unsigned long long > > -ppc64_vmemmap_to_phys(unsigned long vaddr) > > -{ > > - int i; > > - ulong offset; > > - unsigned long long paddr = NOT_PADDR; > > - > > - for (i = 0; i < info->vmemmap_cnt; i++) { > > - if ((vaddr >= info->vmemmap_list[i].virt) && (vaddr < > > - (info->vmemmap_list[i].virt + info->vmemmap_psize))) { > > - offset = vaddr - info->vmemmap_list[i].virt; > > - paddr = info->vmemmap_list[i].phys + offset; > > - break; > > - } > > - } > > - > > - return paddr; > > -} > > - > > static unsigned long long > > ppc64_vtop_level4(unsigned long vaddr) > > { > > @@ -379,6 +369,8 @@ ppc64_vtop_level4(unsigned long vaddr) > > unsigned long long pgd_pte, pud_pte; > > unsigned long long pmd_pte, pte; > > unsigned long long paddr = NOT_PADDR; > > + uint is_hugepage = 0; > > + uint pdshift; > > uint swap = 0; > > > > if (info->page_buf == NULL) { > > @@ -413,6 +405,13 @@ ppc64_vtop_level4(unsigned long vaddr) > > if (!pgd_pte) > > return NOT_PADDR; > > > > + if (IS_HUGEPAGE(pgd_pte)) { > > + is_hugepage = 1; > > + pte = pgd_pte; > > + pdshift = info->l4_shift; > > + goto out; > > + } > > + > > /* > > * Sometimes we don't have level3 pagetable entries > > */ > > @@ -426,6 +425,13 @@ ppc64_vtop_level4(unsigned long vaddr) > > pud_pte = swap64(ULONG((info->page_buf + PAGEOFFSET(page_upper))), swap); > > if (!pud_pte) > > return NOT_PADDR; > > + > > + if (IS_HUGEPAGE(pud_pte)) { > > + is_hugepage = 1; > > + pte = pud_pte; > > + pdshift = info->l3_shift; > > + goto out; > > + } > > } else { > > pud_pte = pgd_pte; > > } > > @@ -440,6 +446,13 @@ ppc64_vtop_level4(unsigned long vaddr) > > if (!(pmd_pte)) > > return NOT_PADDR; > > > > + if (IS_HUGEPAGE(pmd_pte)) { > > + is_hugepage = 1; > > + pte = pmd_pte; > > + pdshift = info->l2_shift; > > + goto out; > > + } > > + > > pmd_pte = pmd_page_vaddr_l4(pmd_pte); > > page_table = (ulong *)(pmd_pte) > > + (BTOP(vaddr) & (info->ptrs_per_l1 - 1)); > > @@ -456,8 +469,40 @@ ppc64_vtop_level4(unsigned long vaddr) > > if (!pte) > > return NOT_PADDR; > > > > - paddr = PAGEBASE(PTOB((pte & info->pte_rpn_mask) >> info->pte_rpn_shift)) > > +out: > > + if (is_hugepage) { > > + paddr = PAGEBASE(PTOB((pte & info->pte_rpn_mask) >> info->pte_rpn_shift)) > > + + (vaddr & ((1UL << pdshift) - 1)); > > + } else { > > + paddr = PAGEBASE(PTOB((pte & info->pte_rpn_mask) >> info->pte_rpn_shift)) > > + PAGEOFFSET(vaddr); > > + } > > + > > + return paddr; > > +} > > + > > +/* > > + * If the vmemmap address translation information is stored in the kernel, > > + * make the translation. > > + */ > > +static unsigned long long > > +ppc64_vmemmap_to_phys(unsigned long vaddr) > > +{ > > + int i; > > + ulong offset; > > + unsigned long long paddr = NOT_PADDR; > > + > > + if (!info->vmemmap_list) > > + return ppc64_vtop_level4(vaddr); > > + > > + for (i = 0; i < info->vmemmap_cnt; i++) { > > + if ((vaddr >= info->vmemmap_list[i].virt) && (vaddr < > > + (info->vmemmap_list[i].virt + info->vmemmap_psize))) { > > + offset = vaddr - info->vmemmap_list[i].virt; > > + paddr = info->vmemmap_list[i].phys + offset; > > + break; > > + } > > + } > > > > return paddr; > > } > > @@ -567,8 +612,8 @@ get_machdep_info_ppc64(void) > > return FALSE; > > } > > > > + info->vmemmap_start = VMEMMAP_REGION_ID << REGION_SHIFT; > > if (SYMBOL(vmemmap_list) != NOT_FOUND_SYMBOL) { > > - info->vmemmap_start = VMEMMAP_REGION_ID << REGION_SHIFT; > > info->vmemmap_end = info->vmemmap_start; > > if (ppc64_vmemmap_init() == FALSE) { > > ERRMSG("Can't get vmemmap list info.\n"); > > diff --git a/makedumpfile.h b/makedumpfile.h > > index 85e5a4932983..056aee191519 100644 > > --- a/makedumpfile.h > > +++ b/makedumpfile.h > > @@ -678,6 +678,12 @@ unsigned long get_kvbase_arm64(void); > > #define REGION_SHIFT (60UL) > > #define VMEMMAP_REGION_ID (0xfUL) > > > > +/* > > + * If PAGE_PTE is set, then it's a leaf PTE for hugepage > > + */ > > +#define PAGE_PTE (1UL << 62) > > +#define IS_HUGEPAGE(pte) (!!((pte) & PAGE_PTE)) > > + > > /* 4-level page table support */ > > > > /* 4K pagesize */ _______________________________________________ kexec mailing list kexec@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/kexec
