1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright 2016, Rashmica Gupta, IBM Corp.
5 * This traverses the kernel virtual memory and dumps the pages that are in
6 * the hash pagetable, along with their flags to
7 * /sys/kernel/debug/kernel_hash_pagetable.
9 * If radix is enabled then there is no hash page table and so no debugfs file
12 #include <linux/debugfs.h>
16 #include <linux/sched.h>
17 #include <linux/seq_file.h>
18 #include <linux/const.h>
20 #include <asm/pgalloc.h>
21 #include <asm/plpar_wrappers.h>
22 #include <linux/memblock.h>
23 #include <asm/firmware.h>
27 const struct addr_marker *marker;
28 unsigned long start_address;
34 unsigned long start_address;
38 static struct addr_marker address_markers[] = {
39 { 0, "Start of kernel VM" },
40 { 0, "vmalloc() Area" },
41 { 0, "vmalloc() End" },
42 { 0, "isa I/O start" },
44 { 0, "phb I/O start" },
46 { 0, "I/O remap start" },
47 { 0, "I/O remap end" },
48 { 0, "vmemmap start" },
61 static const struct flag_info v_flag_array[] = {
64 .val = SLB_VSID_B_256M,
66 .clear = "ssize: 1T ",
68 .mask = HPTE_V_SECONDARY,
69 .val = HPTE_V_SECONDARY,
78 .mask = HPTE_V_BOLTED,
85 static const struct flag_info r_flag_array[] = {
87 .mask = HPTE_R_PP0 | HPTE_R_PP,
91 .mask = HPTE_R_PP0 | HPTE_R_PP,
95 .mask = HPTE_R_PP0 | HPTE_R_PP,
99 .mask = HPTE_R_PP0 | HPTE_R_PP,
103 .mask = HPTE_R_PP0 | HPTE_R_PP,
107 .mask = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
108 .val = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
141 static int calculate_pagesize(struct pg_state *st, int ps, char s[])
143 static const char units[] = "BKMGTPE";
144 const char *unit = units;
146 while (ps > 9 && unit[1]) {
150 seq_printf(st->seq, " %s_ps: %i%c\t", s, 1<<ps, *unit);
154 static void dump_flag_info(struct pg_state *st, const struct flag_info
155 *flag, u64 pte, int num)
159 for (i = 0; i < num; i++, flag++) {
160 const char *s = NULL;
163 /* flag not defined so don't check it */
166 /* Some 'flags' are actually values */
168 val = pte & flag->val;
170 val = val >> flag->shift;
171 seq_printf(st->seq, " %s:%llx", flag->set, val);
173 if ((pte & flag->mask) == flag->val)
178 seq_printf(st->seq, " %s", s);
183 static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
184 unsigned long rpn, int bps, int aps, unsigned long lp)
188 while (ea >= st->marker[1].start_address) {
190 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
192 seq_printf(st->seq, "0x%lx:\t", ea);
193 seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
194 dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
195 seq_printf(st->seq, " rpn: %lx\t", rpn);
196 dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));
198 calculate_pagesize(st, bps, "base");
199 aps_index = calculate_pagesize(st, aps, "actual");
201 seq_printf(st->seq, "LP enc: %lx", lp);
202 seq_putc(st->seq, '\n');
206 static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
209 struct hash_pte *hptep;
210 unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
211 int i, ssize = mmu_kernel_ssize;
212 unsigned long shift = mmu_psize_defs[psize].shift;
215 vsid = get_kernel_vsid(ea, ssize);
216 vpn = hpt_vpn(ea, vsid, ssize);
217 hash = hpt_hash(vpn, shift, ssize);
218 want_v = hpte_encode_avpn(vpn, psize, ssize);
220 /* to check in the secondary hash table, we invert the hash */
223 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
224 for (i = 0; i < HPTES_PER_GROUP; i++) {
225 hptep = htab_address + hpte_group;
226 hpte_v = be64_to_cpu(hptep->v);
228 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
230 *v = be64_to_cpu(hptep->v);
231 *r = be64_to_cpu(hptep->r);
239 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
241 struct hash_pte ptes[4];
242 unsigned long vsid, vpn, hash, hpte_group, want_v;
243 int i, j, ssize = mmu_kernel_ssize;
245 unsigned long shift = mmu_psize_defs[psize].shift;
248 vsid = get_kernel_vsid(ea, ssize);
249 vpn = hpt_vpn(ea, vsid, ssize);
250 hash = hpt_hash(vpn, shift, ssize);
251 want_v = hpte_encode_avpn(vpn, psize, ssize);
253 /* to check in the secondary hash table, we invert the hash */
256 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
257 /* see if we can find an entry in the hpte with this hash */
258 for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
259 lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
261 if (lpar_rc != H_SUCCESS)
263 for (j = 0; j < 4; j++) {
264 if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
265 (ptes[j].v & HPTE_V_VALID)) {
276 static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
277 unsigned long *lp_bits)
279 struct mmu_psize_def entry;
280 unsigned long arpn, mask, lp;
281 int penc = -2, idx = 0, shift;
284 * The LP field has 8 bits. Depending on the actual page size, some of
285 * these bits are concatenated with the APRN to get the RPN. The rest
286 * of the bits in the LP field is the LP value and is an encoding for
287 * the base page size and the actual page size.
289 * - find the mmu entry for our base page size
290 * - go through all page encodings and use the associated mask to
291 * find an encoding that matches our encoding in the LP field.
293 arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
296 entry = mmu_psize_defs[bps];
297 while (idx < MMU_PAGE_COUNT) {
298 penc = entry.penc[idx];
299 if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
300 shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT;
301 mask = (0x1 << (shift)) - 1;
302 if ((lp & mask) == penc) {
303 *aps = mmu_psize_to_shift(idx);
304 *lp_bits = lp & mask;
305 *rpn = arpn >> shift;
313 static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
316 if (IS_ENABLED(CONFIG_PPC_PSERIES) && firmware_has_feature(FW_FEATURE_LPAR))
317 return pseries_find(ea, psize, primary, v, r);
319 return native_find(ea, psize, primary, v, r);
322 static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
326 unsigned long rpn, lp_bits;
327 int base_psize = 0, actual_psize = 0;
329 if (ea < PAGE_OFFSET)
332 /* Look in primary table */
333 slot = base_hpte_find(ea, psize, true, &v, &r);
335 /* Look in secondary table */
337 slot = base_hpte_find(ea, psize, false, &v, &r);
344 * We found an entry in the hash page table:
345 * - check that this has the same base page
346 * - find the actual page size
349 base_psize = mmu_psize_to_shift(psize);
351 if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
352 decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
354 /* 4K actual page size */
356 rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
357 /* In this case there are no LP bits */
361 * We didn't find a matching encoding, so the PTE we found isn't for
364 if (actual_psize == -1)
367 dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
371 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
373 pte_t *pte = pte_offset_kernel(pmd, 0);
374 unsigned long addr, pteval, psize;
377 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
378 addr = start + i * PAGE_SIZE;
379 pteval = pte_val(*pte);
381 if (addr < VMALLOC_END)
382 psize = mmu_vmalloc_psize;
384 psize = mmu_io_psize;
386 /* check for secret 4K mappings */
387 if (IS_ENABLED(CONFIG_PPC_64K_PAGES) &&
388 ((pteval & H_PAGE_COMBO) == H_PAGE_COMBO ||
389 (pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
390 psize = mmu_io_psize;
392 /* check for hashpte */
393 status = hpte_find(st, addr, psize);
395 if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
397 /* found a hpte that is not in the linux page tables */
398 seq_printf(st->seq, "page probably bolted before linux"
399 " pagetables were set: addr:%lx, pteval:%lx\n",
405 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
407 pmd_t *pmd = pmd_offset(pud, 0);
411 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
412 addr = start + i * PMD_SIZE;
415 walk_pte(st, pmd, addr);
419 static void walk_pud(struct pg_state *st, p4d_t *p4d, unsigned long start)
421 pud_t *pud = pud_offset(p4d, 0);
425 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
426 addr = start + i * PUD_SIZE;
429 walk_pmd(st, pud, addr);
433 static void walk_p4d(struct pg_state *st, pgd_t *pgd, unsigned long start)
435 p4d_t *p4d = p4d_offset(pgd, 0);
439 for (i = 0; i < PTRS_PER_P4D; i++, p4d++) {
440 addr = start + i * P4D_SIZE;
443 walk_pud(st, p4d, addr);
447 static void walk_pagetables(struct pg_state *st)
449 pgd_t *pgd = pgd_offset_k(0UL);
454 * Traverse the linux pagetable structure and dump pages that are in
455 * the hash pagetable.
457 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
458 addr = KERN_VIRT_START + i * PGDIR_SIZE;
461 walk_p4d(st, pgd, addr);
466 static void walk_linearmapping(struct pg_state *st)
471 * Traverse the linear mapping section of virtual memory and dump pages
472 * that are in the hash pagetable.
474 unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;
476 for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
477 memblock_end_of_DRAM(); addr += psize)
478 hpte_find(st, addr, mmu_linear_psize);
481 static void walk_vmemmap(struct pg_state *st)
483 struct vmemmap_backing *ptr = vmemmap_list;
485 if (!IS_ENABLED(CONFIG_SPARSEMEM_VMEMMAP))
488 * Traverse the vmemmaped memory and dump pages that are in the hash
492 hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
495 seq_puts(st->seq, "---[ vmemmap end ]---\n");
498 static void populate_markers(void)
500 address_markers[0].start_address = PAGE_OFFSET;
501 address_markers[1].start_address = VMALLOC_START;
502 address_markers[2].start_address = VMALLOC_END;
503 address_markers[3].start_address = ISA_IO_BASE;
504 address_markers[4].start_address = ISA_IO_END;
505 address_markers[5].start_address = PHB_IO_BASE;
506 address_markers[6].start_address = PHB_IO_END;
507 address_markers[7].start_address = IOREMAP_BASE;
508 address_markers[8].start_address = IOREMAP_END;
509 address_markers[9].start_address = H_VMEMMAP_START;
512 static int ptdump_show(struct seq_file *m, void *v)
514 struct pg_state st = {
516 .start_address = PAGE_OFFSET,
517 .marker = address_markers,
520 * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
521 * dump pages that are in the hash pagetable.
523 walk_linearmapping(&st);
524 walk_pagetables(&st);
529 static int ptdump_open(struct inode *inode, struct file *file)
531 return single_open(file, ptdump_show, NULL);
534 static const struct file_operations ptdump_fops = {
538 .release = single_release,
541 static int ptdump_init(void)
543 if (!radix_enabled()) {
545 debugfs_create_file("kernel_hash_pagetable", 0400, NULL, NULL,
550 device_initcall(ptdump_init);