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.

Steven Price committed 6 years ago

Commit f8f0d0b1 parent 9c7869c4 files · +22 −20Browse files

Unified · Split

4 files

arch/arm64/mm/dump.c +3 −3
arch/x86/mm/dump_pagetables.c +10 −9
include/linux/ptdump.h +1 −0
mm/ptdump.c +8 −8

arch/arm64/mm/dump.c+3−3

@@ -176,8 +176,7 @@ struct pg_level { · 175 unmodified lines
176	176	};
177	177
178	178	static struct pg_level pg_level[] = {
179		− {
180		− }, { /* pgd */
	179	+ { /* pgd */
181	180	.name = "PGD",
182	181	.bits = pte_bits,
183	182	.num = ARRAY_SIZE(pte_bits),
@@ -257,7 +256,7 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, · 73 unmodified lines
257	256	if (level >= 0)
258	257	prot = val & pg_level[level].mask;
259	258
260		− if (!st->level) {
	259	+ if (st->level == -1) {
261	260	st->level = level;
262	261	st->current_prot = prot;
263	262	st->start_address = addr;
@@ -351,6 +350,7 @@ void ptdump_check_wx(void) · 87 unmodified lines
351	350	{ 0, NULL},
352	351	{ -1, NULL},
353	352	},
	353	+ .level = -1,
354	354	.check_wx = true,
355	355	.ptdump = {
356	356	.note_page = note_page,

arch/x86/mm/dump_pagetables.c+10−9

@@ -180,7 +180,7 @@ static struct addr_marker address_markers[] = { · 179 unmodified lines
180	180	static void printk_prot(struct seq_file *m, pgprotval_t pr, int level, bool dmsg)
181	181	{
182	182	static const char * const level_name[] =
183		− { "cr3", "pgd", "p4d", "pud", "pmd", "pte" };
	183	+ { "pgd", "p4d", "pud", "pmd", "pte" };
184	184
185	185	if (!(pr & _PAGE_PRESENT)) {
186	186	/* Not present */
@@ -204,12 +204,12 @@ static void printk_prot(struct seq_file *m, pgprotval_t pr, int level, bool dmsg · 17 unmodified lines
204	204	pt_dump_cont_printf(m, dmsg, " ");
205	205
206	206	/* Bit 7 has a different meaning on level 3 vs 4 */
207		− if (level <= 4 && pr & _PAGE_PSE)
	207	+ if (level <= 3 && pr & _PAGE_PSE)
208	208	pt_dump_cont_printf(m, dmsg, "PSE ");
209	209	else
210	210	pt_dump_cont_printf(m, dmsg, " ");
211		− if ((level == 5 && pr & _PAGE_PAT) \|\|
212		− ((level == 4 \|\| level == 3) && pr & _PAGE_PAT_LARGE))
	211	+ if ((level == 4 && pr & _PAGE_PAT) \|\|
	212	+ ((level == 3 \|\| level == 2) && pr & _PAGE_PAT_LARGE))
213	213	pt_dump_cont_printf(m, dmsg, "PAT ");
214	214	else
215	215	pt_dump_cont_printf(m, dmsg, " ");
@@ -271,15 +271,15 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, · 55 unmodified lines
271	271
272	272	new_prot = val & PTE_FLAGS_MASK;
273	273
274		− if (level > 1) {
275		− new_eff = effective_prot(st->prot_levels[level - 2],
	274	+ if (level > 0) {
	275	+ new_eff = effective_prot(st->prot_levels[level - 1],
276	276	new_prot);
277	277	} else {
278	278	new_eff = new_prot;
279	279	}
280	280
281		− if (level > 0)
282		− st->prot_levels[level - 1] = new_eff;
	281	+ if (level >= 0)
	282	+ st->prot_levels[level] = new_eff;
283	283
284	284	/*
285	285	* If we have a "break" in the series, we need to flush the state that
@@ -289,7 +289,7 @@ static void note_page(struct ptdump_state *pt_st, unsigned long addr, int level, · 3 unmodified lines
289	289	cur = st->current_prot;
290	290	eff = st->effective_prot;
291	291
292		− if (!st->level) {
	292	+ if (st->level == -1) {
293	293	/* First entry */
294	294	st->current_prot = new_prot;
295	295	st->effective_prot = new_eff;
@@ -380,6 +380,7 @@ static void ptdump_walk_pgd_level_core(struct seq_file m, pgd_t pgd, · 84 unmodified lines
380	380	.note_page = note_page,
381	381	.range = ptdump_ranges
382	382	},
	383	+ .level = -1,
383	384	.to_dmesg = dmesg,
384	385	.check_wx = checkwx,
385	386	.seq = m

include/linux/ptdump.h+1−0

@@ -11,6 +11,7 @@ struct ptdump_range { · 10 unmodified lines
11	11	};
12	12
13	13	struct ptdump_state {
	14	+ /* level is 0:PGD to 4:PTE, or -1 if unknown */
14	15	void (note_page)(struct ptdump_state st, unsigned long addr,
15	16	int level, unsigned long val);
16	17	const struct ptdump_range *range;

mm/ptdump.c+8−8

@@ -17,7 +17,7 @@ static inline int note_kasan_page_table(struct mm_walk *walk, · 16 unmodified lines
17	17	{
18	18	struct ptdump_state *st = walk->private;
19	19
20		− st->note_page(st, addr, 5, pte_val(kasan_early_shadow_pte[0]));
	20	+ st->note_page(st, addr, 4, pte_val(kasan_early_shadow_pte[0]));
21	21
22	22	walk->action = ACTION_CONTINUE;
23	23
@@ -37,7 +37,7 @@ static int ptdump_pgd_entry(pgd_t *pgd, unsigned long addr, · 13 unmodified lines
37	37	#endif
38	38
39	39	if (pgd_leaf(val))
40		− st->note_page(st, addr, 1, pgd_val(val));
	40	+ st->note_page(st, addr, 0, pgd_val(val));
41	41
42	42	return 0;
43	43	}
@@ -54,7 +54,7 @@ static int ptdump_p4d_entry(p4d_t *p4d, unsigned long addr, · 10 unmodified lines
54	54	#endif
55	55
56	56	if (p4d_leaf(val))
57		− st->note_page(st, addr, 2, p4d_val(val));
	57	+ st->note_page(st, addr, 1, p4d_val(val));
58	58
59	59	return 0;
60	60	}
@@ -71,7 +71,7 @@ static int ptdump_pud_entry(pud_t *pud, unsigned long addr, · 10 unmodified lines
71	71	#endif
72	72
73	73	if (pud_leaf(val))
74		− st->note_page(st, addr, 3, pud_val(val));
	74	+ st->note_page(st, addr, 2, pud_val(val));
75	75
76	76	return 0;
77	77	}
@@ -88,7 +88,7 @@ static int ptdump_pmd_entry(pmd_t *pmd, unsigned long addr, · 10 unmodified lines
88	88	#endif
89	89
90	90	if (pmd_leaf(val))
91		− st->note_page(st, addr, 4, pmd_val(val));
	91	+ st->note_page(st, addr, 3, pmd_val(val));
92	92
93	93	return 0;
94	94	}
@@ -98,7 +98,7 @@ static int ptdump_pte_entry(pte_t *pte, unsigned long addr, · 3 unmodified lines
98	98	{
99	99	struct ptdump_state *st = walk->private;
100	100
101		− st->note_page(st, addr, 5, pte_val(READ_ONCE(*pte)));
	101	+ st->note_page(st, addr, 4, pte_val(READ_ONCE(*pte)));
102	102
103	103	return 0;
104	104	}
@@ -108,7 +108,7 @@ static int ptdump_hole(unsigned long addr, unsigned long next, · 3 unmodified lines
108	108	{
109	109	struct ptdump_state *st = walk->private;
110	110
111		− st->note_page(st, addr, depth + 1, 0);
	111	+ st->note_page(st, addr, depth, 0);
112	112
113	113	return 0;
114	114	}
@@ -135,5 +135,5 @@ void ptdump_walk_pgd(struct ptdump_state st, struct mm_struct mm) · 20 unmodified lines
135	135	up_read(&mm->mmap_sem);
136	136
137	137	/* Flush out the last page */
138		− st->note_page(st, 0, 0, 0);
	138	+ st->note_page(st, 0, -1, 0);
139	139	}