powerpc/mm: Dump hash table
Useful to be able to dump the kernel hash page table to check which pages are hashed along with their sizes and other details. Add a debugfs file to check the hash page table. If radix is enabled (and so there is no hash page table) then this file doesn't exist. To use this the PPC_PTDUMP config option must be selected. Signed-off-by: Rashmica Gupta <rashmicy@gmail.com> [mpe: Fix build with SPARSEMEM_VMEMMAP=n & PSERIES=n] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Rashmica Gupta
Michael Ellerman
parent
8eb07b1870
commit
1515ab9321
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@ -42,4 +42,5 @@ obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
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obj-$(CONFIG_HIGHMEM) += highmem.o
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obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o
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obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_iommu.o
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obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o
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obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o \
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dump_hashpagetable.o
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@ -0,0 +1,551 @@
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/*
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* Copyright 2016, Rashmica Gupta, IBM Corp.
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*
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* This traverses the kernel virtual memory and dumps the pages that are in
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* the hash pagetable, along with their flags to
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* /sys/kernel/debug/kernel_hash_pagetable.
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*
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* If radix is enabled then there is no hash page table and so no debugfs file
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* is generated.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; version 2
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* of the License.
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*/
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#include <linux/debugfs.h>
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#include <linux/fs.h>
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#include <linux/io.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/seq_file.h>
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#include <asm/fixmap.h>
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#include <asm/pgtable.h>
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#include <linux/const.h>
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#include <asm/page.h>
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#include <asm/pgalloc.h>
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#include <asm/plpar_wrappers.h>
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#include <linux/memblock.h>
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#include <asm/firmware.h>
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struct pg_state {
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struct seq_file *seq;
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const struct addr_marker *marker;
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unsigned long start_address;
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unsigned int level;
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u64 current_flags;
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};
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struct addr_marker {
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unsigned long start_address;
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const char *name;
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};
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static struct addr_marker address_markers[] = {
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{ 0, "Start of kernel VM" },
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{ 0, "vmalloc() Area" },
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{ 0, "vmalloc() End" },
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{ 0, "isa I/O start" },
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{ 0, "isa I/O end" },
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{ 0, "phb I/O start" },
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{ 0, "phb I/O end" },
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{ 0, "I/O remap start" },
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{ 0, "I/O remap end" },
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{ 0, "vmemmap start" },
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{ -1, NULL },
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};
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struct flag_info {
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u64 mask;
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u64 val;
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const char *set;
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const char *clear;
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bool is_val;
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int shift;
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};
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static const struct flag_info v_flag_array[] = {
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{
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.mask = SLB_VSID_B,
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.val = SLB_VSID_B_256M,
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.set = "ssize: 256M",
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.clear = "ssize: 1T ",
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}, {
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.mask = HPTE_V_SECONDARY,
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.val = HPTE_V_SECONDARY,
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.set = "secondary",
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.clear = "primary ",
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}, {
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.mask = HPTE_V_VALID,
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.val = HPTE_V_VALID,
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.set = "valid ",
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.clear = "invalid",
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}, {
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.mask = HPTE_V_BOLTED,
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.val = HPTE_V_BOLTED,
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.set = "bolted",
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.clear = "",
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}
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};
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static const struct flag_info r_flag_array[] = {
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{
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.mask = HPTE_R_PP0 | HPTE_R_PP,
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.val = PP_RWXX,
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.set = "prot:RW--",
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}, {
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.mask = HPTE_R_PP0 | HPTE_R_PP,
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.val = PP_RWRX,
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.set = "prot:RWR-",
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}, {
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.mask = HPTE_R_PP0 | HPTE_R_PP,
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.val = PP_RWRW,
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.set = "prot:RWRW",
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}, {
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.mask = HPTE_R_PP0 | HPTE_R_PP,
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.val = PP_RXRX,
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.set = "prot:R-R-",
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}, {
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.mask = HPTE_R_PP0 | HPTE_R_PP,
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.val = PP_RXXX,
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.set = "prot:R---",
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}, {
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.mask = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
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.val = HPTE_R_KEY_HI | HPTE_R_KEY_LO,
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.set = "key",
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.clear = "",
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.is_val = true,
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}, {
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.mask = HPTE_R_R,
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.val = HPTE_R_R,
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.set = "ref",
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.clear = " ",
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}, {
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.mask = HPTE_R_C,
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.val = HPTE_R_C,
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.set = "changed",
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.clear = " ",
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}, {
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.mask = HPTE_R_N,
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.val = HPTE_R_N,
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.set = "no execute",
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}, {
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.mask = HPTE_R_WIMG,
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.val = HPTE_R_W,
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.set = "writethru",
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}, {
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.mask = HPTE_R_WIMG,
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.val = HPTE_R_I,
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.set = "no cache",
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}, {
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.mask = HPTE_R_WIMG,
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.val = HPTE_R_G,
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.set = "guarded",
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}
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};
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static int calculate_pagesize(struct pg_state *st, int ps, char s[])
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{
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static const char units[] = "BKMGTPE";
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const char *unit = units;
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while (ps > 9 && unit[1]) {
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ps -= 10;
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unit++;
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}
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seq_printf(st->seq, " %s_ps: %i%c\t", s, 1<<ps, *unit);
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return ps;
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}
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static void dump_flag_info(struct pg_state *st, const struct flag_info
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*flag, u64 pte, int num)
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{
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unsigned int i;
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for (i = 0; i < num; i++, flag++) {
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const char *s = NULL;
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u64 val;
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/* flag not defined so don't check it */
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if (flag->mask == 0)
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continue;
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/* Some 'flags' are actually values */
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if (flag->is_val) {
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val = pte & flag->val;
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if (flag->shift)
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val = val >> flag->shift;
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seq_printf(st->seq, " %s:%llx", flag->set, val);
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} else {
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if ((pte & flag->mask) == flag->val)
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s = flag->set;
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else
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s = flag->clear;
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if (s)
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seq_printf(st->seq, " %s", s);
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}
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}
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}
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static void dump_hpte_info(struct pg_state *st, unsigned long ea, u64 v, u64 r,
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unsigned long rpn, int bps, int aps, unsigned long lp)
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{
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int aps_index;
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while (ea >= st->marker[1].start_address) {
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st->marker++;
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seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
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}
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seq_printf(st->seq, "0x%lx:\t", ea);
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seq_printf(st->seq, "AVPN:%llx\t", HPTE_V_AVPN_VAL(v));
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dump_flag_info(st, v_flag_array, v, ARRAY_SIZE(v_flag_array));
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seq_printf(st->seq, " rpn: %lx\t", rpn);
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dump_flag_info(st, r_flag_array, r, ARRAY_SIZE(r_flag_array));
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calculate_pagesize(st, bps, "base");
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aps_index = calculate_pagesize(st, aps, "actual");
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if (aps_index != 2)
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seq_printf(st->seq, "LP enc: %lx", lp);
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seq_puts(st->seq, "\n");
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}
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static int native_find(unsigned long ea, int psize, bool primary, u64 *v, u64
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*r)
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{
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struct hash_pte *hptep;
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unsigned long hash, vsid, vpn, hpte_group, want_v, hpte_v;
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int i, ssize = mmu_kernel_ssize;
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unsigned long shift = mmu_psize_defs[psize].shift;
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/* calculate hash */
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vsid = get_kernel_vsid(ea, ssize);
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vpn = hpt_vpn(ea, vsid, ssize);
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hash = hpt_hash(vpn, shift, ssize);
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want_v = hpte_encode_avpn(vpn, psize, ssize);
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/* to check in the secondary hash table, we invert the hash */
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if (!primary)
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hash = ~hash;
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hpte_group = (hash & htab_hash_mask) * HPTES_PER_GROUP;
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for (i = 0; i < HPTES_PER_GROUP; i++) {
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hptep = htab_address + hpte_group;
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hpte_v = be64_to_cpu(hptep->v);
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if (HPTE_V_COMPARE(hpte_v, want_v) && (hpte_v & HPTE_V_VALID)) {
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/* HPTE matches */
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*v = be64_to_cpu(hptep->v);
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*r = be64_to_cpu(hptep->r);
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return 0;
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}
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++hpte_group;
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}
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return -1;
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}
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#ifdef CONFIG_PPC_PSERIES
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static int pseries_find(unsigned long ea, int psize, bool primary, u64 *v, u64 *r)
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{
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struct hash_pte ptes[4];
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unsigned long vsid, vpn, hash, hpte_group, want_v;
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int i, j, ssize = mmu_kernel_ssize;
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long lpar_rc = 0;
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unsigned long shift = mmu_psize_defs[psize].shift;
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/* calculate hash */
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vsid = get_kernel_vsid(ea, ssize);
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vpn = hpt_vpn(ea, vsid, ssize);
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hash = hpt_hash(vpn, shift, ssize);
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want_v = hpte_encode_avpn(vpn, psize, ssize);
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/* to check in the secondary hash table, we invert the hash */
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if (!primary)
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hash = ~hash;
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hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
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/* see if we can find an entry in the hpte with this hash */
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for (i = 0; i < HPTES_PER_GROUP; i += 4, hpte_group += 4) {
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lpar_rc = plpar_pte_read_4(0, hpte_group, (void *)ptes);
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if (lpar_rc != H_SUCCESS)
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continue;
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for (j = 0; j < 4; j++) {
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if (HPTE_V_COMPARE(ptes[j].v, want_v) &&
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(ptes[j].v & HPTE_V_VALID)) {
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/* HPTE matches */
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*v = ptes[j].v;
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*r = ptes[j].r;
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return 0;
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}
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}
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}
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return -1;
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}
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#endif
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static void decode_r(int bps, unsigned long r, unsigned long *rpn, int *aps,
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unsigned long *lp_bits)
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{
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struct mmu_psize_def entry;
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unsigned long arpn, mask, lp;
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int penc = -2, idx = 0, shift;
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/*.
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* The LP field has 8 bits. Depending on the actual page size, some of
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* these bits are concatenated with the APRN to get the RPN. The rest
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* of the bits in the LP field is the LP value and is an encoding for
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* the base page size and the actual page size.
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*
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* - find the mmu entry for our base page size
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* - go through all page encodings and use the associated mask to
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* find an encoding that matches our encoding in the LP field.
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*/
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arpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
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lp = arpn & 0xff;
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entry = mmu_psize_defs[bps];
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while (idx < MMU_PAGE_COUNT) {
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penc = entry.penc[idx];
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if ((penc != -1) && (mmu_psize_defs[idx].shift)) {
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shift = mmu_psize_defs[idx].shift - HPTE_R_RPN_SHIFT;
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mask = (0x1 << (shift)) - 1;
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if ((lp & mask) == penc) {
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*aps = mmu_psize_to_shift(idx);
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*lp_bits = lp & mask;
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*rpn = arpn >> shift;
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return;
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}
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}
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idx++;
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}
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}
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static int base_hpte_find(unsigned long ea, int psize, bool primary, u64 *v,
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u64 *r)
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{
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#ifdef CONFIG_PPC_PSERIES
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if (firmware_has_feature(FW_FEATURE_LPAR))
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return pseries_find(ea, psize, primary, v, r);
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#endif
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return native_find(ea, psize, primary, v, r);
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}
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static unsigned long hpte_find(struct pg_state *st, unsigned long ea, int psize)
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{
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unsigned long slot;
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u64 v = 0, r = 0;
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unsigned long rpn, lp_bits;
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int base_psize = 0, actual_psize = 0;
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if (ea <= PAGE_OFFSET)
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return -1;
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/* Look in primary table */
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slot = base_hpte_find(ea, psize, true, &v, &r);
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/* Look in secondary table */
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if (slot == -1)
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slot = base_hpte_find(ea, psize, true, &v, &r);
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/* No entry found */
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if (slot == -1)
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return -1;
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/*
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* We found an entry in the hash page table:
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* - check that this has the same base page
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* - find the actual page size
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* - find the RPN
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*/
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base_psize = mmu_psize_to_shift(psize);
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if ((v & HPTE_V_LARGE) == HPTE_V_LARGE) {
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decode_r(psize, r, &rpn, &actual_psize, &lp_bits);
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} else {
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/* 4K actual page size */
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actual_psize = 12;
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rpn = (r & HPTE_R_RPN) >> HPTE_R_RPN_SHIFT;
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/* In this case there are no LP bits */
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lp_bits = -1;
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}
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/*
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* We didn't find a matching encoding, so the PTE we found isn't for
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* this address.
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*/
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if (actual_psize == -1)
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return -1;
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dump_hpte_info(st, ea, v, r, rpn, base_psize, actual_psize, lp_bits);
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return 0;
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}
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static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start)
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{
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pte_t *pte = pte_offset_kernel(pmd, 0);
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unsigned long addr, pteval, psize;
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int i, status;
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for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
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addr = start + i * PAGE_SIZE;
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pteval = pte_val(*pte);
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if (addr < VMALLOC_END)
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psize = mmu_vmalloc_psize;
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else
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psize = mmu_io_psize;
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#ifdef CONFIG_PPC_64K_PAGES
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/* check for secret 4K mappings */
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if (((pteval & H_PAGE_COMBO) == H_PAGE_COMBO) ||
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((pteval & H_PAGE_4K_PFN) == H_PAGE_4K_PFN))
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psize = mmu_io_psize;
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#endif
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/* check for hashpte */
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status = hpte_find(st, addr, psize);
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if (((pteval & H_PAGE_HASHPTE) != H_PAGE_HASHPTE)
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&& (status != -1)) {
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/* found a hpte that is not in the linux page tables */
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seq_printf(st->seq, "page probably bolted before linux"
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" pagetables were set: addr:%lx, pteval:%lx\n",
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addr, pteval);
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}
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}
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}
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static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
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{
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pmd_t *pmd = pmd_offset(pud, 0);
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unsigned long addr;
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unsigned int i;
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for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
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addr = start + i * PMD_SIZE;
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if (!pmd_none(*pmd))
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/* pmd exists */
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walk_pte(st, pmd, addr);
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}
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}
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static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
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{
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pud_t *pud = pud_offset(pgd, 0);
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unsigned long addr;
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unsigned int i;
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for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
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addr = start + i * PUD_SIZE;
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if (!pud_none(*pud))
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/* pud exists */
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walk_pmd(st, pud, addr);
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}
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}
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static void walk_pagetables(struct pg_state *st)
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{
|
||||
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_phys_mem_size(); 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_STD_MMU_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);
|
||||
Loading…
Reference in New Issue