2 * Copyright 2016, Rashmica Gupta, IBM Corp.
4 * This traverses the kernel virtual memory and dumps the pages that are in
5 * the hash pagetable, along with their flags to
6 * /sys/kernel/debug/kernel_hash_pagetable.
8 * If radix is enabled then there is no hash page table and so no debugfs file
11 * This program is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU General Public License
13 * as published by the Free Software Foundation; version 2
16 #include <linux/debugfs.h>
20 #include <linux/sched.h>
21 #include <linux/seq_file.h>
22 #include <asm/pgtable.h>
23 #include <linux/const.h>
25 #include <asm/pgalloc.h>
26 #include <asm/plpar_wrappers.h>
27 #include <linux/memblock.h>
28 #include <asm/firmware.h>
32 const struct addr_marker *marker;
33 unsigned long start_address;
39 unsigned long start_address;
43 static struct addr_marker address_markers[] = {
44 { 0, "Start of kernel VM" },
45 { 0, "vmalloc() Area" },
46 { 0, "vmalloc() End" },
47 { 0, "isa I/O start" },
49 { 0, "phb I/O start" },
51 { 0, "I/O remap start" },
52 { 0, "I/O remap end" },
53 { 0, "vmemmap start" },
66 static const struct flag_info v_flag_array[] = {
69 .val = SLB_VSID_B_256M,
71 .clear = "ssize: 1T ",
73 .mask = HPTE_V_SECONDARY,
74 .val = HPTE_V_SECONDARY,
83 .mask = HPTE_V_BOLTED,
90 static const struct flag_info r_flag_array[] = {
92 .mask = HPTE_R_PP0 | HPTE_R_PP,
96 .mask = HPTE_R_PP0 | HPTE_R_PP,
100 .mask = HPTE_R_PP0 | HPTE_R_PP,
104 .mask = HPTE_R_PP0 | HPTE_R_PP,
108 .mask = HPTE_R_PP0 | HPTE_R_PP,
112 .mask = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
113 .val = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
146 static int calculate_pagesize(struct pg_state *st, int ps, char s[])
148 static const char units[] = "BKMGTPE";
149 const char *unit = units;
151 while (ps > 9 && unit[1]) {
155 seq_printf(st->seq, " %s_ps: %i%c\t", s, 1<<ps, *unit);
159 static void dump_flag_info(struct pg_state *st, const struct flag_info
160 *flag, u64 pte, int num)
164 for (i = 0; i < num; i++, flag++) {
165 const char *s = NULL;
168 /* flag not defined so don't check it */
171 /* Some 'flags' are actually values */
173 val = pte & flag->val;
175 val = val >> flag->shift;
176 seq_printf(st->seq, " %s:%llx", flag->set, val);
178 if ((pte & flag->mask) == flag->val)
183 seq_printf(st->seq, " %s", s);
188 static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
189 unsigned long rpn, int bps, int aps, unsigned long lp)
193 while (ea >= st->marker[1].start_address) {
195 seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
197 seq_printf(st->seq, "0x%lx:\t", ea);
198 seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
199 dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
200 seq_printf(st->seq, " rpn: %lx\t", rpn);
201 dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));
203 calculate_pagesize(st, bps, "base");
204 aps_index = calculate_pagesize(st, aps, "actual");
206 seq_printf(st->seq, "LP enc: %lx", lp);
207 seq_putc(st->seq, '\n');
211 static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
214 struct hash_pte *hptep;
215 unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
216 int i, ssize = mmu_kernel_ssize;
217 unsigned long shift = mmu_psize_defs[psize].shift;
220 vsid = get_kernel_vsid(ea, ssize);
221 vpn = hpt_vpn(ea, vsid, ssize);
222 hash = hpt_hash(vpn, shift, ssize);
223 want_v = hpte_encode_avpn(vpn, psize, ssize);
225 /* to check in the secondary hash table, we invert the hash */
228 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
229 for (i = 0; i < HPTES_PER_GROUP; i++) {
230 hptep = htab_address + hpte_group;
231 hpte_v = be64_to_cpu(hptep->v);
233 if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
235 *v = be64_to_cpu(hptep->v);
236 *r = be64_to_cpu(hptep->r);
244 #ifdef CONFIG_PPC_PSERIES
245 static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
247 struct hash_pte ptes[4];
248 unsigned long vsid, vpn, hash, hpte_group, want_v;
249 int i, j, ssize = mmu_kernel_ssize;
251 unsigned long shift = mmu_psize_defs[psize].shift;
254 vsid = get_kernel_vsid(ea, ssize);
255 vpn = hpt_vpn(ea, vsid, ssize);
256 hash = hpt_hash(vpn, shift, ssize);
257 want_v = hpte_encode_avpn(vpn, psize, ssize);
259 /* to check in the secondary hash table, we invert the hash */
262 hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
263 /* see if we can find an entry in the hpte with this hash */
264 for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
265 lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
267 if (lpar_rc != H_SUCCESS)
269 for (j = 0; j < 4; j++) {
270 if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
271 (ptes[j].v & HPTE_V_VALID)) {
283 static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
284 unsigned long *lp_bits)
286 struct mmu_psize_def entry;
287 unsigned long arpn, mask, lp;
288 int penc = -2, idx = 0, shift;
291 * The LP field has 8 bits. Depending on the actual page size, some of
292 * these bits are concatenated with the APRN to get the RPN. The rest
293 * of the bits in the LP field is the LP value and is an encoding for
294 * the base page size and the actual page size.
296 * - find the mmu entry for our base page size
297 * - go through all page encodings and use the associated mask to
298 * find an encoding that matches our encoding in the LP field.
300 arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
303 entry = mmu_psize_defs[bps];
304 while (idx < MMU_PAGE_COUNT) {
305 penc = entry.penc[idx];
306 if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
307 shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT;
308 mask = (0x1 << (shift)) - 1;
309 if ((lp & mask) == penc) {
310 *aps = mmu_psize_to_shift(idx);
311 *lp_bits = lp & mask;
312 *rpn = arpn >> shift;
320 static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
323 #ifdef CONFIG_PPC_PSERIES
324 if (firmware_has_feature(FW_FEATURE_LPAR))
325 return pseries_find(ea, psize, primary, v, r);
327 return native_find(ea, psize, primary, v, r);
330 static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
334 unsigned long rpn, lp_bits;
335 int base_psize = 0, actual_psize = 0;
337 if (ea < PAGE_OFFSET)
340 /* Look in primary table */
341 slot = base_hpte_find(ea, psize, true, &v, &r);
343 /* Look in secondary table */
345 slot = base_hpte_find(ea, psize, false, &v, &r);
352 * We found an entry in the hash page table:
353 * - check that this has the same base page
354 * - find the actual page size
357 base_psize = mmu_psize_to_shift(psize);
359 if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
360 decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
362 /* 4K actual page size */
364 rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
365 /* In this case there are no LP bits */
369 * We didn't find a matching encoding, so the PTE we found isn't for
372 if (actual_psize == -1)
375 dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
379 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
381 pte_t *pte = pte_offset_kernel(pmd, 0);
382 unsigned long addr, pteval, psize;
385 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
386 addr = start + i * PAGE_SIZE;
387 pteval = pte_val(*pte);
389 if (addr < VMALLOC_END)
390 psize = mmu_vmalloc_psize;
392 psize = mmu_io_psize;
393 #ifdef CONFIG_PPC_64K_PAGES
394 /* check for secret 4K mappings */
395 if (((pteval & H_PAGE_COMBO) == H_PAGE_COMBO) ||
396 ((pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
397 psize = mmu_io_psize;
399 /* check for hashpte */
400 status = hpte_find(st, addr, psize);
402 if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
404 /* found a hpte that is not in the linux page tables */
405 seq_printf(st->seq, "page probably bolted before linux"
406 " pagetables were set: addr:%lx, pteval:%lx\n",
412 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
414 pmd_t *pmd = pmd_offset(pud, 0);
418 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
419 addr = start + i * PMD_SIZE;
422 walk_pte(st, pmd, addr);
426 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
428 pud_t *pud = pud_offset(pgd, 0);
432 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
433 addr = start + i * PUD_SIZE;
436 walk_pmd(st, pud, addr);
440 static void walk_pagetables(struct pg_state *st)
442 pgd_t *pgd = pgd_offset_k(0UL);
447 * Traverse the linux pagetable structure and dump pages that are in
448 * the hash pagetable.
450 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
451 addr = KERN_VIRT_START + i * PGDIR_SIZE;
454 walk_pud(st, pgd, addr);
459 static void walk_linearmapping(struct pg_state *st)
464 * Traverse the linear mapping section of virtual memory and dump pages
465 * that are in the hash pagetable.
467 unsigned long psize = 1 << mmu_psize_defs[mmu_linear_psize].shift;
469 for (addr = PAGE_OFFSET; addr < PAGE_OFFSET +
470 memblock_end_of_DRAM(); addr += psize)
471 hpte_find(st, addr, mmu_linear_psize);
474 static void walk_vmemmap(struct pg_state *st)
476 #ifdef CONFIG_SPARSEMEM_VMEMMAP
477 struct vmemmap_backing *ptr = vmemmap_list;
480 * Traverse the vmemmaped memory and dump pages that are in the hash
484 hpte_find(st, ptr->virt_addr, mmu_vmemmap_psize);
487 seq_puts(st->seq, "---[ vmemmap end ]---\n");
491 static void populate_markers(void)
493 address_markers[0].start_address = PAGE_OFFSET;
494 address_markers[1].start_address = VMALLOC_START;
495 address_markers[2].start_address = VMALLOC_END;
496 address_markers[3].start_address = ISA_IO_BASE;
497 address_markers[4].start_address = ISA_IO_END;
498 address_markers[5].start_address = PHB_IO_BASE;
499 address_markers[6].start_address = PHB_IO_END;
500 address_markers[7].start_address = IOREMAP_BASE;
501 address_markers[8].start_address = IOREMAP_END;
502 #ifdef CONFIG_PPC_BOOK3S_64
503 address_markers[9].start_address = H_VMEMMAP_BASE;
505 address_markers[9].start_address = VMEMMAP_BASE;
509 static int ptdump_show(struct seq_file *m, void *v)
511 struct pg_state st = {
513 .start_address = PAGE_OFFSET,
514 .marker = address_markers,
517 * Traverse the 0xc, 0xd and 0xf areas of the kernel virtual memory and
518 * dump pages that are in the hash pagetable.
520 walk_linearmapping(&st);
521 walk_pagetables(&st);
526 static int ptdump_open(struct inode *inode, struct file *file)
528 return single_open(file, ptdump_show, NULL);
531 static const struct file_operations ptdump_fops = {
535 .release = single_release,
538 static int ptdump_init(void)
540 struct dentry *debugfs_file;
542 if (!radix_enabled()) {
544 debugfs_file = debugfs_create_file("kernel_hash_pagetable",
545 0400, NULL, NULL, &ptdump_fops);
546 return debugfs_file ? 0 : -ENOMEM;
550 device_initcall(ptdump_init);