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e47690d756
struct mm_struct is quite large (~1664 bytes) and so allocating on the stack may cause problems as the kernel stack size is small. Since ptdump_walk_pgd_level_core() was only allocating the structure so that it could modify the pgd argument we can instead introduce a pgd override in struct mm_walk and pass this down the call stack to where it is needed. Since the correct mm_struct is now being passed down, it is now also unnecessary to take the mmap_sem semaphore because ptdump_walk_pgd() will now take the semaphore on the real mm. [steven.price@arm.com: restore missed arm64 changes] Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com Signed-off-by: Steven Price <steven.price@arm.com> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Albert Ou <aou@eecs.berkeley.edu> Cc: Alexandre Ghiti <alex@ghiti.fr> Cc: Andy Lutomirski <luto@kernel.org> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David S. Miller <davem@davemloft.net> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Hogan <jhogan@kernel.org> Cc: James Morse <james.morse@arm.com> Cc: Jerome Glisse <jglisse@redhat.com> Cc: "Liang, Kan" <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Burton <paul.burton@mips.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Walmsley <paul.walmsley@sifive.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Will Deacon <will@kernel.org> Cc: Zong Li <zong.li@sifive.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
384 lines
8.4 KiB
C
384 lines
8.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2014, The Linux Foundation. All rights reserved.
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* Debug helper to dump the current kernel pagetables of the system
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* so that we can see what the various memory ranges are set to.
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*
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* Derived from x86 and arm implementation:
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* (C) Copyright 2008 Intel Corporation
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*
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* Author: Arjan van de Ven <arjan@linux.intel.com>
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*/
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#include <linux/debugfs.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/io.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/ptdump.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/kasan.h>
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#include <asm/memory.h>
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#include <asm/pgtable.h>
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#include <asm/pgtable-hwdef.h>
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#include <asm/ptdump.h>
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enum address_markers_idx {
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PAGE_OFFSET_NR = 0,
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PAGE_END_NR,
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#ifdef CONFIG_KASAN
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KASAN_START_NR,
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#endif
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};
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static struct addr_marker address_markers[] = {
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{ PAGE_OFFSET, "Linear Mapping start" },
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{ 0 /* PAGE_END */, "Linear Mapping end" },
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#ifdef CONFIG_KASAN
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{ 0 /* KASAN_SHADOW_START */, "Kasan shadow start" },
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{ KASAN_SHADOW_END, "Kasan shadow end" },
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#endif
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{ MODULES_VADDR, "Modules start" },
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{ MODULES_END, "Modules end" },
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{ VMALLOC_START, "vmalloc() area" },
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{ VMALLOC_END, "vmalloc() end" },
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{ FIXADDR_START, "Fixmap start" },
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{ FIXADDR_TOP, "Fixmap end" },
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{ PCI_IO_START, "PCI I/O start" },
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{ PCI_IO_END, "PCI I/O end" },
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#ifdef CONFIG_SPARSEMEM_VMEMMAP
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{ VMEMMAP_START, "vmemmap start" },
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{ VMEMMAP_START + VMEMMAP_SIZE, "vmemmap end" },
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#endif
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{ -1, NULL },
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};
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#define pt_dump_seq_printf(m, fmt, args...) \
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({ \
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if (m) \
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seq_printf(m, fmt, ##args); \
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})
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#define pt_dump_seq_puts(m, fmt) \
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({ \
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if (m) \
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seq_printf(m, fmt); \
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})
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/*
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* The page dumper groups page table entries of the same type into a single
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* description. It uses pg_state to track the range information while
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* iterating over the pte entries. When the continuity is broken it then
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* dumps out a description of the range.
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*/
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struct pg_state {
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struct ptdump_state ptdump;
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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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int level;
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u64 current_prot;
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bool check_wx;
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unsigned long wx_pages;
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unsigned long uxn_pages;
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};
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struct prot_bits {
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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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};
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static const struct prot_bits pte_bits[] = {
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{
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.mask = PTE_VALID,
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.val = PTE_VALID,
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.set = " ",
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.clear = "F",
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}, {
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.mask = PTE_USER,
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.val = PTE_USER,
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.set = "USR",
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.clear = " ",
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}, {
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.mask = PTE_RDONLY,
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.val = PTE_RDONLY,
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.set = "ro",
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.clear = "RW",
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}, {
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.mask = PTE_PXN,
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.val = PTE_PXN,
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.set = "NX",
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.clear = "x ",
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}, {
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.mask = PTE_SHARED,
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.val = PTE_SHARED,
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.set = "SHD",
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.clear = " ",
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}, {
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.mask = PTE_AF,
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.val = PTE_AF,
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.set = "AF",
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.clear = " ",
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}, {
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.mask = PTE_NG,
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.val = PTE_NG,
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.set = "NG",
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.clear = " ",
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}, {
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.mask = PTE_CONT,
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.val = PTE_CONT,
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.set = "CON",
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.clear = " ",
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}, {
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.mask = PTE_TABLE_BIT,
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.val = PTE_TABLE_BIT,
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.set = " ",
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.clear = "BLK",
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}, {
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.mask = PTE_UXN,
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.val = PTE_UXN,
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.set = "UXN",
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.clear = " ",
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}, {
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.mask = PTE_ATTRINDX_MASK,
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.val = PTE_ATTRINDX(MT_DEVICE_nGnRnE),
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.set = "DEVICE/nGnRnE",
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}, {
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.mask = PTE_ATTRINDX_MASK,
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.val = PTE_ATTRINDX(MT_DEVICE_nGnRE),
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.set = "DEVICE/nGnRE",
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}, {
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.mask = PTE_ATTRINDX_MASK,
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.val = PTE_ATTRINDX(MT_DEVICE_GRE),
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.set = "DEVICE/GRE",
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}, {
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.mask = PTE_ATTRINDX_MASK,
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.val = PTE_ATTRINDX(MT_NORMAL_NC),
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.set = "MEM/NORMAL-NC",
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}, {
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.mask = PTE_ATTRINDX_MASK,
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.val = PTE_ATTRINDX(MT_NORMAL),
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.set = "MEM/NORMAL",
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}
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};
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struct pg_level {
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const struct prot_bits *bits;
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const char *name;
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size_t num;
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u64 mask;
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};
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static struct pg_level pg_level[] = {
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{ /* pgd */
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.name = "PGD",
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.bits = pte_bits,
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.num = ARRAY_SIZE(pte_bits),
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}, { /* p4d */
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.name = "P4D",
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.bits = pte_bits,
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.num = ARRAY_SIZE(pte_bits),
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}, { /* pud */
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.name = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
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.bits = pte_bits,
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.num = ARRAY_SIZE(pte_bits),
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}, { /* pmd */
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.name = (CONFIG_PGTABLE_LEVELS > 2) ? "PMD" : "PGD",
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.bits = pte_bits,
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.num = ARRAY_SIZE(pte_bits),
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}, { /* pte */
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.name = "PTE",
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.bits = pte_bits,
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.num = ARRAY_SIZE(pte_bits),
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},
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};
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static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
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size_t num)
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{
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unsigned i;
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for (i = 0; i < num; i++, bits++) {
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const char *s;
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if ((st->current_prot & bits->mask) == bits->val)
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s = bits->set;
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else
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s = bits->clear;
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if (s)
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pt_dump_seq_printf(st->seq, " %s", s);
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}
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}
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static void note_prot_uxn(struct pg_state *st, unsigned long addr)
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{
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if (!st->check_wx)
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return;
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if ((st->current_prot & PTE_UXN) == PTE_UXN)
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return;
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WARN_ONCE(1, "arm64/mm: Found non-UXN mapping at address %p/%pS\n",
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(void *)st->start_address, (void *)st->start_address);
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st->uxn_pages += (addr - st->start_address) / PAGE_SIZE;
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}
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static void note_prot_wx(struct pg_state *st, unsigned long addr)
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{
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if (!st->check_wx)
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return;
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if ((st->current_prot & PTE_RDONLY) == PTE_RDONLY)
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return;
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if ((st->current_prot & PTE_PXN) == PTE_PXN)
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return;
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WARN_ONCE(1, "arm64/mm: Found insecure W+X mapping at address %p/%pS\n",
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(void *)st->start_address, (void *)st->start_address);
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st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
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}
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static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level,
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unsigned long val)
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{
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struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
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static const char units[] = "KMGTPE";
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u64 prot = 0;
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if (level >= 0)
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prot = val & pg_level[level].mask;
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if (st->level == -1) {
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st->level = level;
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st->current_prot = prot;
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st->start_address = addr;
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
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} else if (prot != st->current_prot || level != st->level ||
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addr >= st->marker[1].start_address) {
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const char *unit = units;
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unsigned long delta;
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if (st->current_prot) {
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note_prot_uxn(st, addr);
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note_prot_wx(st, addr);
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}
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pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
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st->start_address, addr);
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delta = (addr - st->start_address) >> 10;
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while (!(delta & 1023) && unit[1]) {
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delta >>= 10;
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unit++;
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}
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pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
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pg_level[st->level].name);
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if (st->current_prot && pg_level[st->level].bits)
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dump_prot(st, pg_level[st->level].bits,
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pg_level[st->level].num);
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pt_dump_seq_puts(st->seq, "\n");
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if (addr >= st->marker[1].start_address) {
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st->marker++;
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
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}
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st->start_address = addr;
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st->current_prot = prot;
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st->level = level;
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}
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if (addr >= st->marker[1].start_address) {
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st->marker++;
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pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
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}
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}
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void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
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{
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unsigned long end = ~0UL;
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struct pg_state st;
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if (info->base_addr < TASK_SIZE_64)
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end = TASK_SIZE_64;
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st = (struct pg_state){
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.seq = s,
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.marker = info->markers,
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.ptdump = {
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.note_page = note_page,
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.range = (struct ptdump_range[]){
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{info->base_addr, end},
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{0, 0}
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}
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}
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};
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ptdump_walk_pgd(&st.ptdump, info->mm, NULL);
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}
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static void ptdump_initialize(void)
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{
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unsigned i, j;
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for (i = 0; i < ARRAY_SIZE(pg_level); i++)
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if (pg_level[i].bits)
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for (j = 0; j < pg_level[i].num; j++)
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pg_level[i].mask |= pg_level[i].bits[j].mask;
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}
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static struct ptdump_info kernel_ptdump_info = {
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.mm = &init_mm,
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.markers = address_markers,
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.base_addr = PAGE_OFFSET,
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};
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void ptdump_check_wx(void)
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{
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struct pg_state st = {
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.seq = NULL,
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.marker = (struct addr_marker[]) {
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{ 0, NULL},
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{ -1, NULL},
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},
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.level = -1,
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.check_wx = true,
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.ptdump = {
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.note_page = note_page,
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.range = (struct ptdump_range[]) {
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{PAGE_OFFSET, ~0UL},
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{0, 0}
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}
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}
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};
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ptdump_walk_pgd(&st.ptdump, &init_mm, NULL);
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if (st.wx_pages || st.uxn_pages)
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pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu non-UXN pages found\n",
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st.wx_pages, st.uxn_pages);
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else
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pr_info("Checked W+X mappings: passed, no W+X pages found\n");
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}
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static int ptdump_init(void)
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{
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address_markers[PAGE_END_NR].start_address = PAGE_END;
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#ifdef CONFIG_KASAN
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address_markers[KASAN_START_NR].start_address = KASAN_SHADOW_START;
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#endif
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ptdump_initialize();
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ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
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return 0;
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}
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device_initcall(ptdump_init);
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