From: Steven Price <steven.price@xxxxxxx>
Subject: mm: ptdump: reduce level numbers by 1 in note_page()
Rather than having to increment the 'depth' number by 1 in ptdump_hole(),
let's change the meaning of 'level' in note_page() since that makes the
code simplier.
Note that for x86, the level numbers were previously increased by 1 in
commit 45dcd2091363 ("x86/mm/dump_pagetables: Fix printout of p4d level")
and the comment "Bit 7 has a different meaning" was not updated, so this
change also makes the code match the comment again.
Link: http://lkml.kernel.org/r/20191101140942.51554-24-steven.price@xxxxxxx
Signed-off-by: Steven Price <steven.price@xxxxxxx>
Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Alexandre Ghiti <alex@xxxxxxxx>
Cc: Andrey Ryabinin <aryabinin@xxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Dave Jiang <dave.jiang@xxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Heiko Carstens <heiko.carstens@xxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: James Hogan <jhogan@xxxxxxxxxx>
Cc: James Morse <james.morse@xxxxxxx>
Cc: "Liang, Kan" <kan.liang@xxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Paul Burton <paul.burton@xxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
Cc: Shiraz Hashim <shashim@xxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Vineet Gupta <vgupta@xxxxxxxxxxxx>
Cc: Zong Li <zong.li@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arm64/mm/dump.c | 6 +++---
arch/x86/mm/dump_pagetables.c | 19 ++++++++++---------
include/linux/ptdump.h | 1 +
mm/ptdump.c | 16 ++++++++--------
4 files changed, 22 insertions(+), 20 deletions(-)
--- a/arch/arm64/mm/dump.c~mm-ptdump-reduce-level-numbers-by-1-in-note_page
+++ a/arch/arm64/mm/dump.c
@@ -175,8 +175,7 @@ struct pg_level {
};
static struct pg_level pg_level[] = {
- {
- }, { /* pgd */
+ { /* pgd */
.name = "PGD",
.bits = pte_bits,
.num = ARRAY_SIZE(pte_bits),
@@ -256,7 +255,7 @@ static void note_page(struct ptdump_stat
if (level >= 0)
prot = val & pg_level[level].mask;
- if (!st->level) {
+ if (st->level == -1) {
st->level = level;
st->current_prot = prot;
st->start_address = addr;
@@ -350,6 +349,7 @@ void ptdump_check_wx(void)
{ 0, NULL},
{ -1, NULL},
},
+ .level = -1,
.check_wx = true,
.ptdump = {
.note_page = note_page,
--- a/arch/x86/mm/dump_pagetables.c~mm-ptdump-reduce-level-numbers-by-1-in-note_page
+++ a/arch/x86/mm/dump_pagetables.c
@@ -176,7 +176,7 @@ static struct addr_marker address_marker
static void printk_prot(struct seq_file *m, pgprotval_t pr, int level, bool dmsg)
{
static const char * const level_name[] =
- { "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
+ { "pgd", "p4d", "pud", "pmd", "pte" };
if (!(pr & _PAGE_PRESENT)) {
/* Not present */
@@ -200,12 +200,12 @@ static void printk_prot(struct seq_file
pt_dump_cont_printf(m, dmsg, " ");
/* Bit 7 has a different meaning on level 3 vs 4 */
- if (level <= 4 && pr & _PAGE_PSE)
+ if (level <= 3 && pr & _PAGE_PSE)
pt_dump_cont_printf(m, dmsg, "PSE ");
else
pt_dump_cont_printf(m, dmsg, " ");
- if ((level == 5 && pr & _PAGE_PAT) ||
- ((level == 4 || level == 3) && pr & _PAGE_PAT_LARGE))
+ if ((level == 4 && pr & _PAGE_PAT) ||
+ ((level == 3 || level == 2) && pr & _PAGE_PAT_LARGE))
pt_dump_cont_printf(m, dmsg, "PAT ");
else
pt_dump_cont_printf(m, dmsg, " ");
@@ -267,15 +267,15 @@ static void note_page(struct ptdump_stat
new_prot = val & PTE_FLAGS_MASK;
- if (level > 1) {
- new_eff = effective_prot(st->prot_levels[level - 2],
+ if (level > 0) {
+ new_eff = effective_prot(st->prot_levels[level - 1],
new_prot);
} else {
new_eff = new_prot;
}
- if (level > 0)
- st->prot_levels[level - 1] = new_eff;
+ if (level >= 0)
+ st->prot_levels[level] = new_eff;
/*
* If we have a "break" in the series, we need to flush the state that
@@ -285,7 +285,7 @@ static void note_page(struct ptdump_stat
cur = st->current_prot;
eff = st->effective_prot;
- if (!st->level) {
+ if (st->level == -1) {
/* First entry */
st->current_prot = new_prot;
st->effective_prot = new_eff;
@@ -376,6 +376,7 @@ static void ptdump_walk_pgd_level_core(s
.note_page = note_page,
.range = ptdump_ranges
},
+ .level = -1,
.to_dmesg = dmesg,
.check_wx = checkwx,
.seq = m
--- a/include/linux/ptdump.h~mm-ptdump-reduce-level-numbers-by-1-in-note_page
+++ a/include/linux/ptdump.h
@@ -11,6 +11,7 @@ struct ptdump_range {
};
struct ptdump_state {
+ /* level is 0:PGD to 4:PTE, or -1 if unknown */
void (*note_page)(struct ptdump_state *st, unsigned long addr,
int level, unsigned long val);
const struct ptdump_range *range;
--- a/mm/ptdump.c~mm-ptdump-reduce-level-numbers-by-1-in-note_page
+++ a/mm/ptdump.c
@@ -11,7 +11,7 @@ static int ptdump_pgd_entry(pgd_t *pgd,
pgd_t val = READ_ONCE(*pgd);
if (pgd_leaf(val))
- st->note_page(st, addr, 1, pgd_val(val));
+ st->note_page(st, addr, 0, pgd_val(val));
return 0;
}
@@ -23,7 +23,7 @@ static int ptdump_p4d_entry(p4d_t *p4d,
p4d_t val = READ_ONCE(*p4d);
if (p4d_leaf(val))
- st->note_page(st, addr, 2, p4d_val(val));
+ st->note_page(st, addr, 1, p4d_val(val));
return 0;
}
@@ -35,7 +35,7 @@ static int ptdump_pud_entry(pud_t *pud,
pud_t val = READ_ONCE(*pud);
if (pud_leaf(val))
- st->note_page(st, addr, 3, pud_val(val));
+ st->note_page(st, addr, 2, pud_val(val));
return 0;
}
@@ -47,7 +47,7 @@ static int ptdump_pmd_entry(pmd_t *pmd,
pmd_t val = READ_ONCE(*pmd);
if (pmd_leaf(val))
- st->note_page(st, addr, 4, pmd_val(val));
+ st->note_page(st, addr, 3, pmd_val(val));
return 0;
}
@@ -57,7 +57,7 @@ static int ptdump_pte_entry(pte_t *pte,
{
struct ptdump_state *st = walk->private;
- st->note_page(st, addr, 5, pte_val(READ_ONCE(*pte)));
+ st->note_page(st, addr, 4, pte_val(READ_ONCE(*pte)));
return 0;
}
@@ -75,7 +75,7 @@ static inline int note_kasan_page_table(
{
struct ptdump_state *st = walk->private;
- st->note_page(st, addr, 5, pte_val(kasan_early_shadow_pte[0]));
+ st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
return 1;
}
@@ -115,7 +115,7 @@ static int ptdump_hole(unsigned long add
{
struct ptdump_state *st = walk->private;
- st->note_page(st, addr, depth + 1, 0);
+ st->note_page(st, addr, depth, 0);
return 0;
}
@@ -147,5 +147,5 @@ void ptdump_walk_pgd(struct ptdump_state
up_read(&mm->mmap_sem);
/* Flush out the last page */
- st->note_page(st, 0, 0, 0);
+ st->note_page(st, 0, -1, 0);
}
_
