diff options
Diffstat (limited to 'arch/powerpc/mm/dump_hashpagetable.c')
| -rw-r--r-- | arch/powerpc/mm/dump_hashpagetable.c | 550 |
1 files changed, 550 insertions, 0 deletions
diff --git a/arch/powerpc/mm/dump_hashpagetable.c b/arch/powerpc/mm/dump_hashpagetable.c new file mode 100644 index 000000000..b430e4e08 --- /dev/null +++ b/arch/powerpc/mm/dump_hashpagetable.c @@ -0,0 +1,550 @@ +/* + * 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. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; version 2 + * of the License. + */ +#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; +} + +#ifdef CONFIG_PPC_PSERIES +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 != H_SUCCESS) + 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; +} +#endif + +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) +{ +#ifdef CONFIG_PPC_PSERIES + if (firmware_has_feature(FW_FEATURE_LPAR)) + return pseries_find(ea, psize, primary, v, r); +#endif + 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; +#ifdef CONFIG_PPC_64K_PAGES + /* check for secret 4K mappings */ + if (((pteval & H_PAGE_COMBO) == H_PAGE_COMBO) || + ((pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN)) + psize = mmu_io_psize; +#endif + /* 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) +{ +#ifdef CONFIG_SPARSEMEM_VMEMMAP + struct vmemmap_backing *ptr = vmemmap_list; + + /* + * 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"); +#endif +} + +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; +#ifdef CONFIG_PPC_BOOK3S_64 + address_markers[9].start_address = H_VMEMMAP_BASE; +#else + address_markers[9].start_address = VMEMMAP_BASE; +#endif +} + +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); |