| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Copyright 2016, Rashmica Gupta, IBM Corp. |
| * |
| * This traverses the kernel virtual memory and dumps the pages that are in |
| * the hash pagetable, along with their flags to |
| * /sys/kernel/debug/kernel_hash_pagetable. |
| * |
| * If radix is enabled then there is no hash page table and so no debugfs file |
| * is generated. |
| */ |
| #include <linux/debugfs.h> |
| #include <linux/fs.h> |
| #include <linux/io.h> |
| #include <linux/mm.h> |
| #include <linux/sched.h> |
| #include <linux/seq_file.h> |
| #include <asm/pgtable.h> |
| #include <linux/const.h> |
| #include <asm/page.h> |
| #include <asm/pgalloc.h> |
| #include <asm/plpar_wrappers.h> |
| #include <linux/memblock.h> |
| #include <asm/firmware.h> |
| |
| struct pg_state { |
| struct seq_file *seq; |
| const struct addr_marker *marker; |
| unsigned long start_address; |
| unsigned int level; |
| u64 current_flags; |
| }; |
| |
| struct addr_marker { |
| unsigned long start_address; |
| const char *name; |
| }; |
| |
| static struct addr_marker address_markers[] = { |
| { 0, "Start of kernel VM" }, |
| { 0, "vmalloc() Area" }, |
| { 0, "vmalloc() End" }, |
| { 0, "isa I/O start" }, |
| { 0, "isa I/O end" }, |
| { 0, "phb I/O start" }, |
| { 0, "phb I/O end" }, |
| { 0, "I/O remap start" }, |
| { 0, "I/O remap end" }, |
| { 0, "vmemmap start" }, |
| { -1, NULL }, |
| }; |
| |
| struct flag_info { |
| u64 mask; |
| u64 val; |
| const char *set; |
| const char *clear; |
| bool is_val; |
| int shift; |
| }; |
| |
| static const struct flag_info v_flag_array[] = { |
| { |
| .mask = SLB_VSID_B, |
| .val = SLB_VSID_B_256M, |
| .set = "ssize: 256M", |
| .clear = "ssize: 1T ", |
| }, { |
| .mask = HPTE_V_SECONDARY, |
| .val = HPTE_V_SECONDARY, |
| .set = "secondary", |
| .clear = "primary ", |
| }, { |
| .mask = HPTE_V_VALID, |
| .val = HPTE_V_VALID, |
| .set = "valid ", |
| .clear = "invalid", |
| }, { |
| .mask = HPTE_V_BOLTED, |
| .val = HPTE_V_BOLTED, |
| .set = "bolted", |
| .clear = "", |
| } |
| }; |
| |
| static const struct flag_info r_flag_array[] = { |
| { |
| .mask = HPTE_R_PP0 | HPTE_R_PP, |
| .val = PP_RWXX, |
| .set = "prot:RW--", |
| }, { |
| .mask = HPTE_R_PP0 | HPTE_R_PP, |
| .val = PP_RWRX, |
| .set = "prot:RWR-", |
| }, { |
| .mask = HPTE_R_PP0 | HPTE_R_PP, |
| .val = PP_RWRW, |
| .set = "prot:RWRW", |
| }, { |
| .mask = HPTE_R_PP0 | HPTE_R_PP, |
| .val = PP_RXRX, |
| .set = "prot:R-R-", |
| }, { |
| .mask = HPTE_R_PP0 | HPTE_R_PP, |
| .val = PP_RXXX, |
| .set = "prot:R---", |
| }, { |
| .mask = HPTE_R_KEY_HI | HPTE_R_KEY_LO, |
| .val = HPTE_R_KEY_HI | HPTE_R_KEY_LO, |
| .set = "key", |
| .clear = "", |
| .is_val = true, |
| }, { |
| .mask = HPTE_R_R, |
| .val = HPTE_R_R, |
| .set = "ref", |
| .clear = " ", |
| }, { |
| .mask = HPTE_R_C, |
| .val = HPTE_R_C, |
| .set = "changed", |
| .clear = " ", |
| }, { |
| .mask = HPTE_R_N, |
| .val = HPTE_R_N, |
| .set = "no execute", |
| }, { |
| .mask = HPTE_R_WIMG, |
| .val = HPTE_R_W, |
| .set = "writethru", |
| }, { |
| .mask = HPTE_R_WIMG, |
| .val = HPTE_R_I, |
| .set = "no cache", |
| }, { |
| .mask = HPTE_R_WIMG, |
| .val = HPTE_R_G, |
| .set = "guarded", |
| } |
| }; |
| |
| static int calculate_pagesize(struct pg_state *st, int ps, char s[]) |
| { |
| static const char units[] = "BKMGTPE"; |
| const char *unit = units; |
| |
| while (ps > 9 && unit[1]) { |
| ps -= 10; |
| unit++; |
| } |
| seq_printf(st->seq, " %s_ps: %i%c\t", s, 1<<ps, *unit); |
| return ps; |
| } |
| |
| static void dump_flag_info(struct pg_state *st, const struct flag_info |
| *flag, u64 pte, int num) |
| { |
| unsigned int i; |
| |
| for (i = 0; i < num; i++, flag++) { |
| const char *s = NULL; |
| u64 val; |
| |
| /* flag not defined so don't check it */ |
| if (flag->mask == 0) |
| continue; |
| /* Some 'flags' are actually values */ |
| if (flag->is_val) { |
| val = pte & flag->val; |
| if (flag->shift) |
| val = val >> flag->shift; |
| seq_printf(st->seq, " %s:%llx", flag->set, val); |
| } else { |
| if ((pte & flag->mask) == flag->val) |
| s = flag->set; |
| else |
| s = flag->clear; |
| if (s) |
| seq_printf(st->seq, " %s", s); |
| } |
| } |
| } |
| |
| static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r, |
| unsigned long rpn, int bps, int aps, unsigned long lp) |
| { |
| int aps_index; |
| |
| while (ea >= st->marker[1].start_address) { |
| st->marker++; |
| seq_printf(st->seq, "---[ %s ]---\n", st->marker->name); |
| } |
| seq_printf(st->seq, "0x%lx:\t", ea); |
| seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v)); |
| dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array)); |
| seq_printf(st->seq, " rpn: %lx\t", rpn); |
| dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array)); |
| |
| calculate_pagesize(st, bps, "base"); |
| aps_index = calculate_pagesize(st, aps, "actual"); |
| if (aps_index != 2) |
| seq_printf(st->seq, "LP enc: %lx", lp); |
| seq_putc(st->seq, '\n'); |
| } |
| |
| |
| static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64 |
| *r) |
| { |
| struct hash_pte *hptep; |
| unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v; |
| int i, ssize = mmu_kernel_ssize; |
| unsigned long shift = mmu_psize_defs[psize].shift; |
| |
| /* calculate hash */ |
| vsid = get_kernel_vsid(ea, ssize); |
| vpn = hpt_vpn(ea, vsid, ssize); |
| hash = hpt_hash(vpn, shift, ssize); |
| want_v = hpte_encode_avpn(vpn, psize, ssize); |
| |
| /* to check in the secondary hash table, we invert the hash */ |
| if (!primary) |
| hash = ~hash; |
| hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP; |
| for (i = 0; i < HPTES_PER_GROUP; i++) { |
| hptep = htab_address + hpte_group; |
| hpte_v = be64_to_cpu(hptep->v); |
| |
| if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) { |
| /* HPTE matches */ |
| *v = be64_to_cpu(hptep->v); |
| *r = be64_to_cpu(hptep->r); |
| return 0; |
| } |
| ++hpte_group; |
| } |
| return -1; |
| } |
| |
| static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r) |
| { |
| struct hash_pte ptes[4]; |
| unsigned long vsid, vpn, hash, hpte_group, want_v; |
| int i, j, ssize = mmu_kernel_ssize; |
| long lpar_rc = 0; |
| unsigned long shift = mmu_psize_defs[psize].shift; |
| |
| /* calculate hash */ |
| vsid = get_kernel_vsid(ea, ssize); |
| vpn = hpt_vpn(ea, vsid, ssize); |
| hash = hpt_hash(vpn, shift, ssize); |
| want_v = hpte_encode_avpn(vpn, psize, ssize); |
| |
| /* to check in the secondary hash table, we invert the hash */ |
| if (!primary) |
| hash = ~hash; |
| hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP; |
| /* see if we can find an entry in the hpte with this hash */ |
| for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) { |
| lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes); |
| |
| if (lpar_rc) |
| continue; |
| for (j = 0; j < 4; j++) { |
| if (HPTE_V_COMPARE(ptes[j].v, want_v) && |
| (ptes[j].v & HPTE_V_VALID)) { |
| /* HPTE matches */ |
| *v = ptes[j].v; |
| *r = ptes[j].r; |
| return 0; |
| } |
| } |
| } |
| return -1; |
| } |
| |
| static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps, |
| unsigned long *lp_bits) |
| { |
| struct mmu_psize_def entry; |
| unsigned long arpn, mask, lp; |
| int penc = -2, idx = 0, shift; |
| |
| /*. |
| * The LP field has 8 bits. Depending on the actual page size, some of |
| * these bits are concatenated with the APRN to get the RPN. The rest |
| * of the bits in the LP field is the LP value and is an encoding for |
| * the base page size and the actual page size. |
| * |
| * - find the mmu entry for our base page size |
| * - go through all page encodings and use the associated mask to |
| * find an encoding that matches our encoding in the LP field. |
| */ |
| arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT; |
| lp = arpn & 0xff; |
| |
| entry = mmu_psize_defs[bps]; |
| while (idx < MMU_PAGE_COUNT) { |
| penc = entry.penc[idx]; |
| if ((penc != -1) && (mmu_psize_defs[idx].shift)) { |
| shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT; |
| mask = (0x1 << (shift)) - 1; |
| if ((lp & mask) == penc) { |
| *aps = mmu_psize_to_shift(idx); |
| *lp_bits = lp & mask; |
| *rpn = arpn >> shift; |
| return; |
| } |
| } |
| idx++; |
| } |
| } |
| |
| static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v, |
| u64 *r) |
| { |
| if (IS_ENABLED(CONFIG_PPC_PSERIES) && firmware_has_feature(FW_FEATURE_LPAR)) |
| return pseries_find(ea, psize, primary, v, r); |
| |
| return native_find(ea, psize, primary, v, r); |
| } |
| |
| static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize) |
| { |
| unsigned long slot; |
| u64 v = 0, r = 0; |
| unsigned long rpn, lp_bits; |
| int base_psize = 0, actual_psize = 0; |
| |
| if (ea < PAGE_OFFSET) |
| return -1; |
| |
| /* Look in primary table */ |
| slot = base_hpte_find(ea, psize, true, &v, &r); |
| |
| /* Look in secondary table */ |
| if (slot == -1) |
| slot = base_hpte_find(ea, psize, false, &v, &r); |
| |
| /* No entry found */ |
| if (slot == -1) |
| return -1; |
| |
| /* |
| * We found an entry in the hash page table: |
| * - check that this has the same base page |
| * - find the actual page size |
| * - find the RPN |
| */ |
| base_psize = mmu_psize_to_shift(psize); |
| |
| if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) { |
| decode_r(psize, r, &rpn, &actual_psize, &lp_bits); |
| } else { |
| /* 4K actual page size */ |
| actual_psize = 12; |
| rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT; |
| /* In this case there are no LP bits */ |
| lp_bits = -1; |
| } |
| /* |
| * We didn't find a matching encoding, so the PTE we found isn't for |
| * this address. |
| */ |
| if (actual_psize == -1) |
| return -1; |
| |
| dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits); |
| return 0; |
| } |
| |
| static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start) |
| { |
| pte_t *pte = pte_offset_kernel(pmd, 0); |
| unsigned long addr, pteval, psize; |
| int i, status; |
| |
| for (i = 0; i < PTRS_PER_PTE; i++, pte++) { |
| addr = start + i * PAGE_SIZE; |
| pteval = pte_val(*pte); |
| |
| if (addr < VMALLOC_END) |
| psize = mmu_vmalloc_psize; |
| else |
| psize = mmu_io_psize; |
| |
| /* check for secret 4K mappings */ |
| if (IS_ENABLED(CONFIG_PPC_64K_PAGES) && |
| ((pteval & H_PAGE_COMBO) == H_PAGE_COMBO || |
| (pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN)) |
| psize = mmu_io_psize; |
| |
| /* check for hashpte */ |
| status = hpte_find(st, addr, psize); |
| |
| if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE) |
| && (status != -1)) { |
| /* found a hpte that is not in the linux page tables */ |
| seq_printf(st->seq, "page probably bolted before linux" |
| " pagetables were set: addr:%lx, pteval:%lx\n", |
| addr, pteval); |
| } |
| } |
| } |
| |
| static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start) |
| { |
| pmd_t *pmd = pmd_offset(pud, 0); |
| unsigned long addr; |
| unsigned int i; |
| |
| for (i = 0; i < PTRS_PER_PMD; i++, pmd++) { |
| addr = start + i * PMD_SIZE; |
| if (!pmd_none(*pmd)) |
| /* pmd exists */ |
| walk_pte(st, pmd, addr); |
| } |
| } |
| |
| static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start) |
| { |
| pud_t *pud = pud_offset(pgd, 0); |
| unsigned long addr; |
| unsigned int i; |
| |
| for (i = 0; i < PTRS_PER_PUD; i++, pud++) { |
| addr = start + i * PUD_SIZE; |
| if (!pud_none(*pud)) |
| /* pud exists */ |
| walk_pmd(st, pud, addr); |
| } |
| } |
| |
| static void walk_pagetables(struct pg_state *st) |
| { |
| pgd_t *pgd = pgd_offset_k(0UL); |
| unsigned int i; |
| unsigned long addr; |
| |
| /* |
| * Traverse the linux pagetable structure and dump pages that are in |
| * the hash pagetable. |
| */ |
| for (i = 0; i < PTRS_PER_PGD; i++, pgd++) { |
| addr = KERN_VIRT_START + i * PGDIR_SIZE; |
| if (!pgd_none(*pgd)) |
| /* pgd exists */ |
| walk_pud(st, pgd, addr); |
| } |
| } |
| |
| |
| static void walk_linearmapping(struct pg_state *st) |
| { |
| unsigned long addr; |
| |
| /* |
| * Traverse the linear mapping section of virtual memory and dump pages |
| * that are in the hash pagetable. |
| */ |
| unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift; |
| |
| for (addr = PAGE_OFFSET; addr < PAGE_OFFSET + |
| memblock_end_of_DRAM(); addr += psize) |
| hpte_find(st, addr, mmu_linear_psize); |
| } |
| |
| static void walk_vmemmap(struct pg_state *st) |
| { |
| struct vmemmap_backing *ptr = vmemmap_list; |
| |
| if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP)) |
| return; |
| /* |
| * Traverse the vmemmaped memory and dump pages that are in the hash |
| * pagetable. |
| */ |
| while (ptr->list) { |
| hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize); |
| ptr = ptr->list; |
| } |
| seq_puts(st->seq, "---[ vmemmap end ]---\n"); |
| } |
| |
| static void populate_markers(void) |
| { |
| address_markers[0].start_address = PAGE_OFFSET; |
| address_markers[1].start_address = VMALLOC_START; |
| address_markers[2].start_address = VMALLOC_END; |
| address_markers[3].start_address = ISA_IO_BASE; |
| address_markers[4].start_address = ISA_IO_END; |
| address_markers[5].start_address = PHB_IO_BASE; |
| address_markers[6].start_address = PHB_IO_END; |
| address_markers[7].start_address = IOREMAP_BASE; |
| address_markers[8].start_address = IOREMAP_END; |
| address_markers[9].start_address = H_VMEMMAP_START; |
| } |
| |
| static int ptdump_show(struct seq_file *m, void *v) |
| { |
| struct pg_state st = { |
| .seq = m, |
| .start_address = PAGE_OFFSET, |
| .marker = address_markers, |
| }; |
| /* |
| * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and |
| * dump pages that are in the hash pagetable. |
| */ |
| walk_linearmapping(&st); |
| walk_pagetables(&st); |
| walk_vmemmap(&st); |
| return 0; |
| } |
| |
| static int ptdump_open(struct inode *inode, struct file *file) |
| { |
| return single_open(file, ptdump_show, NULL); |
| } |
| |
| static const struct file_operations ptdump_fops = { |
| .open = ptdump_open, |
| .read = seq_read, |
| .llseek = seq_lseek, |
| .release = single_release, |
| }; |
| |
| static int ptdump_init(void) |
| { |
| struct dentry *debugfs_file; |
| |
| if (!radix_enabled()) { |
| populate_markers(); |
| debugfs_file = debugfs_create_file("kernel_hash_pagetable", |
| 0400, NULL, NULL, &ptdump_fops); |
| return debugfs_file ? 0 : -ENOMEM; |
| } |
| return 0; |
| } |
| device_initcall(ptdump_init); |