Now walk_page_range() can walk kernel page tables, we can switch the
arm64 ptdump code over to using it, simplifying the code.

Signed-off-by: Steven Price <steven.pr...@arm.com>
---
 arch/arm64/Kconfig                 |   1 +
 arch/arm64/Kconfig.debug           |  19 +----
 arch/arm64/include/asm/ptdump.h    |   8 +-
 arch/arm64/mm/Makefile             |   4 +-
 arch/arm64/mm/dump.c               | 117 ++++++++++-------------------
 arch/arm64/mm/ptdump_debugfs.c     |   2 +-
 drivers/firmware/efi/arm-runtime.c |   2 +-
 7 files changed, 48 insertions(+), 105 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 3adcec05b1f6..5a32c87f37c6 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -105,6 +105,7 @@ config ARM64
        select GENERIC_IRQ_SHOW
        select GENERIC_IRQ_SHOW_LEVEL
        select GENERIC_PCI_IOMAP
+       select GENERIC_PTDUMP
        select GENERIC_SCHED_CLOCK
        select GENERIC_SMP_IDLE_THREAD
        select GENERIC_STRNCPY_FROM_USER
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug
index cf09010d825f..1c906d932d6b 100644
--- a/arch/arm64/Kconfig.debug
+++ b/arch/arm64/Kconfig.debug
@@ -1,22 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 
-config ARM64_PTDUMP_CORE
-       def_bool n
-
-config ARM64_PTDUMP_DEBUGFS
-       bool "Export kernel pagetable layout to userspace via debugfs"
-       depends on DEBUG_KERNEL
-       select ARM64_PTDUMP_CORE
-       select DEBUG_FS
-        help
-         Say Y here if you want to show the kernel pagetable layout in a
-         debugfs file. This information is only useful for kernel developers
-         who are working in architecture specific areas of the kernel.
-         It is probably not a good idea to enable this feature in a production
-         kernel.
-
-         If in doubt, say N.
-
 config PID_IN_CONTEXTIDR
        bool "Write the current PID to the CONTEXTIDR register"
        help
@@ -42,7 +25,7 @@ config ARM64_RANDOMIZE_TEXT_OFFSET
 
 config DEBUG_WX
        bool "Warn on W+X mappings at boot"
-       select ARM64_PTDUMP_CORE
+       select PTDUMP_CORE
        ---help---
          Generate a warning if any W+X mappings are found at boot.
 
diff --git a/arch/arm64/include/asm/ptdump.h b/arch/arm64/include/asm/ptdump.h
index 0b8e7269ec82..38187f74e089 100644
--- a/arch/arm64/include/asm/ptdump.h
+++ b/arch/arm64/include/asm/ptdump.h
@@ -5,7 +5,7 @@
 #ifndef __ASM_PTDUMP_H
 #define __ASM_PTDUMP_H
 
-#ifdef CONFIG_ARM64_PTDUMP_CORE
+#ifdef CONFIG_PTDUMP_CORE
 
 #include <linux/mm_types.h>
 #include <linux/seq_file.h>
@@ -21,15 +21,15 @@ struct ptdump_info {
        unsigned long                   base_addr;
 };
 
-void ptdump_walk_pgd(struct seq_file *s, struct ptdump_info *info);
-#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
+void ptdump_walk(struct seq_file *s, struct ptdump_info *info);
+#ifdef CONFIG_PTDUMP_DEBUGFS
 void ptdump_debugfs_register(struct ptdump_info *info, const char *name);
 #else
 static inline void ptdump_debugfs_register(struct ptdump_info *info,
                                           const char *name) { }
 #endif
 void ptdump_check_wx(void);
-#endif /* CONFIG_ARM64_PTDUMP_CORE */
+#endif /* CONFIG_PTDUMP_CORE */
 
 #ifdef CONFIG_DEBUG_WX
 #define debug_checkwx()        ptdump_check_wx()
diff --git a/arch/arm64/mm/Makefile b/arch/arm64/mm/Makefile
index 849c1df3d214..d91030f0ffee 100644
--- a/arch/arm64/mm/Makefile
+++ b/arch/arm64/mm/Makefile
@@ -4,8 +4,8 @@ obj-y                           := dma-mapping.o extable.o 
fault.o init.o \
                                   ioremap.o mmap.o pgd.o mmu.o \
                                   context.o proc.o pageattr.o
 obj-$(CONFIG_HUGETLB_PAGE)     += hugetlbpage.o
-obj-$(CONFIG_ARM64_PTDUMP_CORE)        += dump.o
-obj-$(CONFIG_ARM64_PTDUMP_DEBUGFS)     += ptdump_debugfs.o
+obj-$(CONFIG_PTDUMP_CORE)      += dump.o
+obj-$(CONFIG_PTDUMP_DEBUGFS)   += ptdump_debugfs.o
 obj-$(CONFIG_NUMA)             += numa.o
 obj-$(CONFIG_DEBUG_VIRTUAL)    += physaddr.o
 KASAN_SANITIZE_physaddr.o      += n
diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index 82b3a7fdb4a6..5cc71ad567b4 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -15,6 +15,7 @@
 #include <linux/io.h>
 #include <linux/init.h>
 #include <linux/mm.h>
+#include <linux/ptdump.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
 
@@ -65,10 +66,11 @@ static const struct addr_marker address_markers[] = {
  * dumps out a description of the range.
  */
 struct pg_state {
+       struct ptdump_state ptdump;
        struct seq_file *seq;
        const struct addr_marker *marker;
        unsigned long start_address;
-       unsigned level;
+       int level;
        u64 current_prot;
        bool check_wx;
        unsigned long wx_pages;
@@ -168,6 +170,10 @@ static struct pg_level pg_level[] = {
                .name   = "PGD",
                .bits   = pte_bits,
                .num    = ARRAY_SIZE(pte_bits),
+       }, { /* p4d */
+               .name   = "P4D",
+               .bits   = pte_bits,
+               .num    = ARRAY_SIZE(pte_bits),
        }, { /* pud */
                .name   = (CONFIG_PGTABLE_LEVELS > 3) ? "PUD" : "PGD",
                .bits   = pte_bits,
@@ -230,11 +236,15 @@ static void note_prot_wx(struct pg_state *st, unsigned 
long addr)
        st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
 }
 
-static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
-                               u64 val)
+static void note_page(struct ptdump_state *pt_st, unsigned long addr, int 
level,
+                               unsigned long val)
 {
+       struct pg_state *st = container_of(pt_st, struct pg_state, ptdump);
        static const char units[] = "KMGTPE";
-       u64 prot = val & pg_level[level].mask;
+       u64 prot = 0;
+
+       if (level >= 0)
+               prot = val & pg_level[level].mask;
 
        if (!st->level) {
                st->level = level;
@@ -282,85 +292,27 @@ static void note_page(struct pg_state *st, unsigned long 
addr, unsigned level,
 
 }
 
-static void walk_pte(struct pg_state *st, pmd_t *pmdp, unsigned long start,
-                    unsigned long end)
-{
-       unsigned long addr = start;
-       pte_t *ptep = pte_offset_kernel(pmdp, start);
-
-       do {
-               note_page(st, addr, 4, READ_ONCE(pte_val(*ptep)));
-       } while (ptep++, addr += PAGE_SIZE, addr != end);
-}
-
-static void walk_pmd(struct pg_state *st, pud_t *pudp, unsigned long start,
-                    unsigned long end)
-{
-       unsigned long next, addr = start;
-       pmd_t *pmdp = pmd_offset(pudp, start);
-
-       do {
-               pmd_t pmd = READ_ONCE(*pmdp);
-               next = pmd_addr_end(addr, end);
-
-               if (pmd_none(pmd) || pmd_sect(pmd)) {
-                       note_page(st, addr, 3, pmd_val(pmd));
-               } else {
-                       BUG_ON(pmd_bad(pmd));
-                       walk_pte(st, pmdp, addr, next);
-               }
-       } while (pmdp++, addr = next, addr != end);
-}
-
-static void walk_pud(struct pg_state *st, pgd_t *pgdp, unsigned long start,
-                    unsigned long end)
+void ptdump_walk(struct seq_file *s, struct ptdump_info *info)
 {
-       unsigned long next, addr = start;
-       pud_t *pudp = pud_offset(pgdp, start);
-
-       do {
-               pud_t pud = READ_ONCE(*pudp);
-               next = pud_addr_end(addr, end);
-
-               if (pud_none(pud) || pud_sect(pud)) {
-                       note_page(st, addr, 2, pud_val(pud));
-               } else {
-                       BUG_ON(pud_bad(pud));
-                       walk_pmd(st, pudp, addr, next);
-               }
-       } while (pudp++, addr = next, addr != end);
-}
+       unsigned long end = ~0UL;
+       struct pg_state st;
 
-static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
-                    unsigned long start)
-{
-       unsigned long end = (start < TASK_SIZE_64) ? TASK_SIZE_64 : 0;
-       unsigned long next, addr = start;
-       pgd_t *pgdp = pgd_offset(mm, start);
-
-       do {
-               pgd_t pgd = READ_ONCE(*pgdp);
-               next = pgd_addr_end(addr, end);
-
-               if (pgd_none(pgd)) {
-                       note_page(st, addr, 1, pgd_val(pgd));
-               } else {
-                       BUG_ON(pgd_bad(pgd));
-                       walk_pud(st, pgdp, addr, next);
-               }
-       } while (pgdp++, addr = next, addr != end);
-}
+       if (info->base_addr < TASK_SIZE_64)
+               end = TASK_SIZE_64;
 
-void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
-{
-       struct pg_state st = {
-               .seq = m,
+       st = (struct pg_state){
+               .seq = s,
                .marker = info->markers,
+               .ptdump = {
+                       .note_page = note_page,
+                       .range = (struct ptdump_range[]){
+                               {info->base_addr, end},
+                               {0, 0}
+                       }
+               }
        };
 
-       walk_pgd(&st, info->mm, info->base_addr);
-
-       note_page(&st, 0, 0, 0);
+       ptdump_walk_pgd(&st.ptdump, info->mm);
 }
 
 static void ptdump_initialize(void)
@@ -388,10 +340,17 @@ void ptdump_check_wx(void)
                        { -1, NULL},
                },
                .check_wx = true,
+               .ptdump = {
+                       .note_page = note_page,
+                       .range = (struct ptdump_range[]) {
+                               {VA_START, ~0UL},
+                               {0, 0}
+                       }
+               }
        };
 
-       walk_pgd(&st, &init_mm, VA_START);
-       note_page(&st, 0, 0, 0);
+       ptdump_walk_pgd(&st.ptdump, &init_mm);
+
        if (st.wx_pages || st.uxn_pages)
                pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found, %lu 
non-UXN pages found\n",
                        st.wx_pages, st.uxn_pages);
diff --git a/arch/arm64/mm/ptdump_debugfs.c b/arch/arm64/mm/ptdump_debugfs.c
index 064163f25592..1f2eae3e988b 100644
--- a/arch/arm64/mm/ptdump_debugfs.c
+++ b/arch/arm64/mm/ptdump_debugfs.c
@@ -7,7 +7,7 @@
 static int ptdump_show(struct seq_file *m, void *v)
 {
        struct ptdump_info *info = m->private;
-       ptdump_walk_pgd(m, info);
+       ptdump_walk(m, info);
        return 0;
 }
 DEFINE_SHOW_ATTRIBUTE(ptdump);
diff --git a/drivers/firmware/efi/arm-runtime.c 
b/drivers/firmware/efi/arm-runtime.c
index e2ac5fa5531b..1283685f9c20 100644
--- a/drivers/firmware/efi/arm-runtime.c
+++ b/drivers/firmware/efi/arm-runtime.c
@@ -27,7 +27,7 @@
 
 extern u64 efi_system_table;
 
-#ifdef CONFIG_ARM64_PTDUMP_DEBUGFS
+#if defined(CONFIG_PTDUMP_DEBUGFS) && defined(CONFIG_ARM64)
 #include <asm/ptdump.h>
 
 static struct ptdump_info efi_ptdump_info = {
-- 
2.20.1

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