* [v2 PATCH 1/2] powerpc/pagetable: Add option to dump the linux pagetables
@ 2016-03-29 2:37 Rashmica Gupta
2016-03-29 2:37 ` [PATCH 2/2] powerpc/pagetable: Add option to dump kernel hashpagetable Rashmica Gupta
0 siblings, 1 reply; 2+ messages in thread
From: Rashmica Gupta @ 2016-03-29 2:37 UTC (permalink / raw)
To: linuxppc-dev, mpe
Useful to be able to dump the kernels page tables to check permissions
and memory types - derived from arm64's implementation.
Add a debugfs file to check the page tables. To use this the PPC_PTDUMP
config option must be selected.
Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
Do not check for COMBO pages if default page size is 4K.
arch/powerpc/Kconfig.debug | 12 +
arch/powerpc/mm/Makefile | 1 +
arch/powerpc/mm/dump_linuxpagetables.c | 398 +++++++++++++++++++++++++++++++++
3 files changed, 411 insertions(+)
create mode 100644 arch/powerpc/mm/dump_linuxpagetables.c
diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 638f9ce740f5..26a60effea1a 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -344,4 +344,16 @@ config FAIL_IOMMU
If you are unsure, say N.
+config PPC_PTDUMP
+ bool "Export kernel pagetable layout to userspace via debugfs"
+ depends on DEBUG_KERNEL
+ select DEBUG_FS
+ help
+ This option exports the state of the kernel pagetables to a
+ debugfs file. This is only useful for kernel developers who are
+ working in architecture specific areas of the kernel - probably
+ not a good idea to enable this feature in a production kernel.
+
+ If you are unsure, say N.
+
endmenu
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index adfee3f1aeb9..6935c6204fbc 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -41,3 +41,4 @@ obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
obj-$(CONFIG_HIGHMEM) += highmem.o
obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o
obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_iommu.o
+obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o
diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c
new file mode 100644
index 000000000000..566ae4487a19
--- /dev/null
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -0,0 +1,398 @@
+/*
+ * Copyright 2016, Rashmica Gupta, IBM Corp.
+ *
+ * This traverses the kernel pagetables and dumps the
+ * information about the used sections of memory to
+ * /sys/kernel/debug/kernel_pagetables.
+ *
+ * Derived from the arm64 implementation:
+ * Copyright (c) 2014, The Linux Foundation, Laura Abbott.
+ * (C) Copyright 2008 Intel Corporation, Arjan van de Ven.
+ *
+ * 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/fixmap.h>
+#include <asm/pgtable.h>
+#include <linux/const.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+
+struct addr_marker {
+ unsigned long start_address;
+ const char *name;
+};
+
+static struct addr_marker address_markers[] = {
+ { VMALLOC_START, "vmalloc() Area" },
+ { VMALLOC_END, "vmalloc() End" },
+ { ISA_IO_BASE, "isa I/O start" },
+ { ISA_IO_END, "isa I/O end" },
+ { PHB_IO_BASE, "phb I/O start" },
+ { PHB_IO_END, "phb I/O end" },
+ { IOREMAP_BASE, "I/O remap start" },
+ { IOREMAP_END, "I/O remap end" },
+ { -1, NULL },
+};
+
+/*
+ * To visualise what is happening,
+ *
+ * - PTRS_PER_P** = how many entries there are in the corresponding P**
+ * - P**_SHIFT = how many bits of the address we use to index into the
+ * corresponding P**
+ * - P**_SIZE is how much memory we can access through the table - not the
+ * size of the table itself.
+ * P**={PGD, PUD, PMD, PTE}
+ *
+ *
+ * Each entry of the PGD points to a PUD. Each entry of a PUD points to a
+ * PMD. Each entry of a PMD points to a PTE. And every PTE entry points to
+ * a page.
+ *
+ * In the case where there are only 3 levels, the PUD is folded into the
+ * PGD: every PUD has only one entry which points to the PMD.
+ *
+ * The page dumper groups page table entries of the same type into a single
+ * description. It uses pg_state to track the range information while
+ * iterating over the PTE entries. When the continuity is broken it then
+ * dumps out a description of the range - ie PTEs that are virtually contiguous
+ * with the same PTE flags are chunked together. This is to make it clear how
+ * different areas of the kernel virtual memory are used.
+ *
+ */
+struct pg_state {
+ struct seq_file *seq;
+ const struct addr_marker *marker;
+ unsigned long start_address;
+ unsigned level;
+ u64 current_flags;
+};
+
+struct flag_info {
+ u64 mask;
+ u64 val;
+ const char *set;
+ const char *clear;
+ bool is_val;
+ int shift;
+};
+
+static const struct flag_info flag_array[] = {
+ {
+ .mask = _PAGE_USER,
+ .val = _PAGE_USER,
+ .set = "user",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_RW,
+ .val = _PAGE_RW,
+ .set = "rw",
+ .clear = "ro",
+ }, {
+ .mask = _PAGE_EXEC,
+ .val = _PAGE_EXEC,
+ .set = " X ",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_PTE,
+ .val = _PAGE_PTE,
+ .set = "pte",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_PRESENT,
+ .val = _PAGE_PRESENT,
+ .set = "present",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_HASHPTE,
+ .val = _PAGE_HASHPTE,
+ .set = "hpte",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_GUARDED,
+ .val = _PAGE_GUARDED,
+ .set = "guarded",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_DIRTY,
+ .val = _PAGE_DIRTY,
+ .set = "dirty",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_ACCESSED,
+ .val = _PAGE_ACCESSED,
+ .set = "accessed",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_WRITETHRU,
+ .val = _PAGE_WRITETHRU,
+ .set = "write through",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_NO_CACHE,
+ .val = _PAGE_NO_CACHE,
+ .set = "no cache",
+ .clear = " ",
+ }, {
+ .mask = _PAGE_BUSY,
+ .val = _PAGE_BUSY,
+ .set = "busy",
+ }, {
+#ifdef CONFIG_PPC_64K_PAGES
+ .mask = _PAGE_COMBO,
+ .val = _PAGE_COMBO,
+ .set = "combo",
+ }, {
+ .mask = _PAGE_4K_PFN,
+ .val = _PAGE_4K_PFN,
+ .set = "4K_pfn",
+ }, {
+#endif
+ .mask = _PAGE_F_GIX,
+ .val = _PAGE_F_GIX,
+ .set = "f_gix",
+ .is_val = true,
+ .shift = _PAGE_F_GIX_SHIFT,
+ }, {
+ .mask = _PAGE_F_SECOND,
+ .val = _PAGE_F_SECOND,
+ .set = "f_second",
+ }, {
+ .mask = _PAGE_SPECIAL,
+ .val = _PAGE_SPECIAL,
+ .set = "special",
+ }
+};
+
+struct pgtable_level {
+ const struct flag_info *flag;
+ size_t num;
+ u64 mask;
+};
+
+static struct pgtable_level pg_level[] = {
+ {
+ }, { /* pgd */
+ .flag = flag_array,
+ .num = ARRAY_SIZE(flag_array),
+ }, { /* pud */
+ .flag = flag_array,
+ .num = ARRAY_SIZE(flag_array),
+ }, { /* pmd */
+ .flag = flag_array,
+ .num = ARRAY_SIZE(flag_array),
+ }, { /* pte */
+ .flag = flag_array,
+ .num = ARRAY_SIZE(flag_array),
+ },
+};
+
+static void dump_flag(struct pg_state *st, const struct flag_info *flag,
+ size_t num)
+{
+ unsigned i;
+
+ for (i = 0; i < num; i++, flag++) {
+ const char *s;
+ u64 val;
+
+ /* flag not defined so don't check it */
+ if (flag->mask == 0)
+ continue;
+
+ if (flag->is_val) {
+ val = st->current_flags & flag->val;
+ if (flag->shift)
+ val = val >> flag->shift;
+ seq_printf(st->seq, " %s:%llx", flag->set, val);
+ } else {
+ if ((st->current_flags & flag->mask) == flag->val)
+ s = flag->set;
+ else
+ s = flag->clear;
+
+ if (s)
+ seq_printf(st->seq, " %s", s);
+ }
+ st->current_flags &= ~flag->mask;
+ }
+ if (st->current_flags != 0)
+ seq_printf(st->seq, " unknown flags:%llx", st->current_flags);
+}
+
+static void dump_addr(struct pg_state *st, unsigned long addr)
+{
+ static const char units[] = "KMGTPE";
+ const char *unit = units;
+ unsigned long delta;
+
+ seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr-1);
+ delta = (addr - st->start_address) >> 10;
+ /* Work out what appropriate unit to use */
+ while (!(delta & 1023) && unit[1]) {
+ delta >>= 10;
+ unit++;
+ }
+ seq_printf(st->seq, "%9lu%c", delta, *unit);
+
+}
+
+static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
+ u64 val)
+{
+ u64 flag = val & pg_level[level].mask;
+
+ /* At first no level is set */
+ if (!st->level) {
+ st->level = level;
+ st->current_flags = flag;
+ st->start_address = addr;
+ seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ /*
+ * Dump the section of virtual memory when:
+ * - the PTE flags from one entry to the next differs.
+ * - we change levels in the tree.
+ * - the address is in a different section of memory and is thus
+ * used for a different purpose, regardless of the flags.
+ */
+ } else if (flag != st->current_flags || level != st->level ||
+ addr >= st->marker[1].start_address) {
+
+ /* Check the PTE flags */
+ if (st->current_flags) {
+ dump_addr(st, addr);
+
+ /* Dump all the flags */
+ if (pg_level[st->level].flag)
+ dump_flag(st, pg_level[st->level].flag,
+ pg_level[st->level].num);
+ seq_puts(st->seq, "\n");
+ }
+
+ /* Address indicates we have passed the end of the
+ * current section of virtual memory
+ */
+ while (addr >= st->marker[1].start_address) {
+ st->marker++;
+ seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ }
+ st->start_address = addr;
+ st->current_flags = flag;
+ st->level = level;
+ }
+}
+
+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;
+ unsigned i;
+
+ for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
+ addr = start + i * PAGE_SIZE;
+ note_page(st, addr, 4, pte_val(*pte));
+ }
+}
+
+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 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);
+ else
+ note_page(st, addr, 3, pmd_val(*pmd));
+ }
+}
+
+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 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);
+ else
+ note_page(st, addr, 2, pud_val(*pud));
+ }
+}
+
+static void walk_pgd(struct pg_state *st, unsigned long start)
+{
+ pgd_t *pgd = pgd_offset_k(0UL);
+ unsigned i;
+ unsigned long addr;
+
+ for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
+ addr = start + i * PGDIR_SIZE;
+ if (!pgd_none(*pgd))
+ /* pgd exists */
+ walk_pud(st, pgd, addr);
+ else
+ note_page(st, addr, 1, pgd_val(*pgd));
+ }
+}
+
+static int ptdump_show(struct seq_file *m, void *v)
+{
+ struct pg_state st = {
+ .seq = m,
+ .start_address = KERN_VIRT_START,
+ .marker = address_markers,
+ };
+ /* Traverse kernel page tables */
+ walk_pgd(&st, KERN_VIRT_START);
+ note_page(&st, 0, 0, 0);
+ 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 void build_pgtable_complete_mask(void)
+{
+ unsigned i, j;
+
+ for (i = 0; i < ARRAY_SIZE(pg_level); i++)
+ if (pg_level[i].flag)
+ for (j = 0; j < pg_level[i].num; j++)
+ pg_level[i].mask |= pg_level[i].flag[j].mask;
+}
+
+static int ptdump_init(void)
+{
+ struct dentry *debugfs_file;
+
+ build_pgtable_complete_mask();
+ debugfs_file = debugfs_create_file("kernel_pagetables", 0400, NULL,
+ NULL, &ptdump_fops);
+ return debugfs_file ? 0 : -ENOMEM;
+}
+device_initcall(ptdump_init);
--
2.5.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
* [PATCH 2/2] powerpc/pagetable: Add option to dump kernel hashpagetable
2016-03-29 2:37 [v2 PATCH 1/2] powerpc/pagetable: Add option to dump the linux pagetables Rashmica Gupta
@ 2016-03-29 2:37 ` Rashmica Gupta
0 siblings, 0 replies; 2+ messages in thread
From: Rashmica Gupta @ 2016-03-29 2:37 UTC (permalink / raw)
To: linuxppc-dev, mpe
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 page tables. To use this the PPC_PTDUMP
config option must be selected.
Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
---
arch/powerpc/mm/Makefile | 3 +-
arch/powerpc/mm/dump_hashpagetable.c | 501 +++++++++++++++++++++++++++++++++++
2 files changed, 503 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/mm/dump_hashpagetable.c
diff --git a/arch/powerpc/mm/Makefile b/arch/powerpc/mm/Makefile
index 6935c6204fbc..0bd48b345ff3 100644
--- a/arch/powerpc/mm/Makefile
+++ b/arch/powerpc/mm/Makefile
@@ -41,4 +41,5 @@ obj-$(CONFIG_NOT_COHERENT_CACHE) += dma-noncoherent.o
obj-$(CONFIG_HIGHMEM) += highmem.o
obj-$(CONFIG_PPC_COPRO_BASE) += copro_fault.o
obj-$(CONFIG_SPAPR_TCE_IOMMU) += mmu_context_iommu.o
-obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o
+obj-$(CONFIG_PPC_PTDUMP) += dump_linuxpagetables.o \
+ dump_hashpagetable.o
diff --git a/arch/powerpc/mm/dump_hashpagetable.c b/arch/powerpc/mm/dump_hashpagetable.c
new file mode 100644
index 000000000000..fbd746ffe26a
--- /dev/null
+++ b/arch/powerpc/mm/dump_hashpagetable.c
@@ -0,0 +1,501 @@
+/*
+ * 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.
+ *
+ * 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/fixmap.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 addr_marker {
+ unsigned long start_address;
+ const char *name;
+};
+
+static struct addr_marker address_markers[] = {
+ { PAGE_OFFSET, "Start of kernel VM"},
+ { VMALLOC_START, "vmalloc() Area" },
+ { VMALLOC_END, "vmalloc() End" },
+ { ISA_IO_BASE, "isa I/O start" },
+ { ISA_IO_END, "isa I/O end" },
+ { PHB_IO_BASE, "phb I/O start" },
+ { PHB_IO_END, "phb I/O end" },
+ { IOREMAP_BASE, "I/O remap start" },
+ { IOREMAP_END, "I/O remap end" },
+ { VMEMMAP_BASE, "vmemmap start" },
+ { -1, NULL },
+};
+
+struct pg_state {
+ struct seq_file *seq;
+ const struct addr_marker *marker;
+ unsigned long start_address;
+ unsigned level;
+ u64 current_flags;
+};
+
+struct flag_info {
+ u64 mask;
+ u64 val;
+ const char *set;
+ const char *clear;
+ bool is_val;
+};
+
+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 void dump_flag_info(struct pg_state *st, const struct flag_info
+ *flag, u64 pte, int num)
+{
+ unsigned i;
+
+ for (i = 0; i < num; i++, flag++) {
+ const char *s = NULL;
+
+ if (flag->is_val) {
+ seq_printf(st->seq, " %s:%llx", flag->set, pte &
+ flag->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)
+{
+ static const char units[] = "BKMGTPE";
+ const char *unit = units;
+
+ 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));
+
+ while (bps > 9 && unit[1]) {
+ bps -= 10;
+ unit++;
+ }
+ seq_printf(st->seq, " base_ps: %i%c\t", 1<<bps, *unit);
+ unit = units;
+ while (aps > 9 && unit[1]) {
+ aps -= 10;
+ unit++;
+ }
+ seq_printf(st->seq, "actual_ps: %i%c", 1<<aps, *unit);
+ if (aps != 2)
+ seq_printf(st->seq, "\tLP enc: %lx", lp);
+ seq_puts(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) & ~0x7UL;
+ /* 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;
+}
+
+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 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 */
+ if (firmware_has_feature(FW_FEATURE_LPAR))
+ slot = pseries_find(ea, psize, true, &v, &r);
+ else
+ slot = native_find(ea, psize, true, &v, &r);
+
+ /* Look in secondary table */
+ if (slot == -1) {
+ if (firmware_has_feature(FW_FEATURE_LPAR))
+ slot = pseries_find(ea, psize, false, &v, &r);
+ else
+ slot = native_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 & _PAGE_COMBO) == _PAGE_COMBO) ||
+ ((pteval & _PAGE_4K_PFN) == _PAGE_4K_PFN))
+ psize = mmu_io_psize;
+#endif
+ /* check for hashpte */
+ status = hpte_find(st, addr, psize);
+
+ if (((pteval & _PAGE_HASHPTE) != _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 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 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_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_pagetables(struct pg_state *st)
+{
+ pgd_t *pgd = pgd_offset_k(0UL);
+ unsigned 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 = VMALLOC_START + i * PGDIR_SIZE;
+ if (!pgd_none(*pgd))
+ /* pgd exists */
+ walk_pud(st, pgd, addr);
+ }
+}
+
+static void walk_vmemmap(struct pg_state *st)
+{
+ 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");
+}
+
+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;
+
+ debugfs_file = debugfs_create_file("kernel_hash_pagetable", 0400,
+ NULL, NULL, &ptdump_fops);
+ return debugfs_file ? 0 : -ENOMEM;
+}
+device_initcall(ptdump_init);
--
2.5.0
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2016-03-29 2:37 [v2 PATCH 1/2] powerpc/pagetable: Add option to dump the linux pagetables Rashmica Gupta
2016-03-29 2:37 ` [PATCH 2/2] powerpc/pagetable: Add option to dump kernel hashpagetable Rashmica Gupta
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