[PATCH v16 23/25] arm64: mm: Convert mm/dump.c to use walk_page_range()

Steven Price
2019-12-06T13:54:59Z

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

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Steven Price <steven.price@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/mmu.c | 4 +-
arch/arm64/mm/ptdump_debugfs.c | 2 +-
drivers/firmware/efi/arm-runtime.c | 2 +-
8 files changed, 50 insertions(+), 107 deletions(-)

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b1b4476ddb83..43aa1de727f4 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -103,6 +103,7 @@ 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 93f9f77582ae..9d9b740a86d2 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>

@@ -75,10 +76,11 @@ static 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;
@@ -178,6 +180,10 @@ 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,
@@ -240,11 +246,15 @@ 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;
@@ -292,85 +302,27 @@ 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)
@@ -398,10 +350,17 @@ void ptdump_check_wx(void)
{ -1, NULL},
},
.check_wx = true,
+ .ptdump = {
+ .note_page = note_page,
+ .range = (struct ptdump_range[]) {
+ {PAGE_OFFSET, ~0UL},
+ {0, 0}
+ }
+ }
};

- walk_pgd(&st, &init_mm, PAGE_OFFSET);
- 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/mmu.c b/arch/arm64/mm/mmu.c
index 5a3b15a14a7f..36e8f4f74433 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -943,13 +943,13 @@ int __init arch_ioremap_pud_supported(void)
* SW table walks can't handle removal of intermediate entries.
*/
return IS_ENABLED(CONFIG_ARM64_4K_PAGES) &&
- !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
+ !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
}

int __init arch_ioremap_pmd_supported(void)
{
/* See arch_ioremap_pud_supported() */
- return !IS_ENABLED(CONFIG_ARM64_PTDUMP_DEBUGFS);
+ return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
}

int pud_set_huge(pud_t *pudp, phys_addr_t phys, pgprot_t prot)
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 899b803842bb..9dda2602c862 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