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Date: Mon, 18 Feb 2019 12:25:20 +0000 (UTC)
From: Christophe Leroy <christophe.leroy@....fr>
To: Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Paul Mackerras <paulus@...ba.org>,
Michael Ellerman <mpe@...erman.id.au>
Cc: linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] powerpc: dump as a single line areas mapping a single
physical page.
When using KASAN, there are parts of the shadow area where all
pages are mapped to the kasan_early_shadow_page. It is pointless
to dump one line for each of those pages (in the example below there
are 7168 entries pointing to the same physical page).
~# cat /sys/kernel/debug/kernel_page_tables
...
---[ kasan shadow mem start ]---
0xf7c00000-0xf8bfffff 0x06fac000 16M rw present dirty accessed
0xf8c00000-0xf8c03fff 0x00cd0000 16K r present dirty accessed
0xf8c04000-0xf8c07fff 0x00cd0000 16K r present dirty accessed
0xf8c08000-0xf8c0bfff 0x00cd0000 16K r present dirty accessed
0xf8c0c000-0xf8c0ffff 0x00cd0000 16K r present dirty accessed
0xf8c10000-0xf8c13fff 0x00cd0000 16K r present dirty accessed
... 7168 identical lines
0xffbfc000-0xffbfffff 0x00cd0000 16K r present dirty accessed
---[ kasan shadow mem end ]---
...
This patch modifies linux table dump to dump as a single line areas
where all addresses points to the same physical page. That physical
address is put inside [] to show that all virt pages points to the
same phys page.
~# cat /sys/kernel/debug/kernel_page_tables
...
---[ kasan shadow mem start ]---
0xf7c00000-0xf8bfffff 0x06fac000 16M rw present dirty accessed
0xf8c00000-0xffbfffff [0x00cd0000] 16K r present dirty accessed
---[ kasan shadow mem end ]---
...
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
arch/powerpc/mm/dump_linuxpagetables.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/arch/powerpc/mm/dump_linuxpagetables.c b/arch/powerpc/mm/dump_linuxpagetables.c
index 6aa41669ac1a..b0da447197d4 100644
--- a/arch/powerpc/mm/dump_linuxpagetables.c
+++ b/arch/powerpc/mm/dump_linuxpagetables.c
@@ -143,14 +143,19 @@ static void dump_addr(struct pg_state *st, unsigned long addr)
unsigned long delta;
#ifdef CONFIG_PPC64
- seq_printf(st->seq, "0x%016lx-0x%016lx ", st->start_address, addr-1);
- seq_printf(st->seq, "0x%016lx ", st->start_pa);
+#define REG "0x%016lx"
#else
- seq_printf(st->seq, "0x%08lx-0x%08lx ", st->start_address, addr - 1);
- seq_printf(st->seq, "0x%08lx ", st->start_pa);
+#define REG "0x%08lx"
#endif
- delta = (addr - st->start_address) >> 10;
+ seq_printf(st->seq, REG "-" REG " ", st->start_address, addr - 1);
+ if (st->start_pa == st->last_pa && st->start_address + PAGE_SIZE != addr) {
+ seq_printf(st->seq, "[" REG "]", st->start_pa);
+ delta = PAGE_SIZE >> 10;
+ } else {
+ seq_printf(st->seq, " " REG " ", st->start_pa);
+ delta = (addr - st->start_address) >> 10;
+ }
/* Work out what appropriate unit to use */
while (!(delta & 1023) && unit[1]) {
delta >>= 10;
@@ -184,7 +189,8 @@ static void note_page(struct pg_state *st, unsigned long addr,
*/
} else if (flag != st->current_flags || level != st->level ||
addr >= st->marker[1].start_address ||
- pa != st->last_pa + PAGE_SIZE) {
+ (pa != st->last_pa + PAGE_SIZE &&
+ (pa != st->start_pa || st->start_pa != st->last_pa))) {
/* Check the PTE flags */
if (st->current_flags) {
--
2.13.3
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