[PATCHv2 2/4] arm64: dump: Make the page table dumping seq_file optional

From: Laura Abbott
Date: Wed Oct 12 2016 - 18:33:01 EST



The page table dumping code always assumes it will be dumping to a
seq_file to userspace. Future code will be taking advantage of
the page table dumping code but will not need the seq_file. Make
the seq_file optional for these cases.

Acked-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Laura Abbott <labbott@xxxxxxxxxx>
---
v2: Tweak commit text per Mark Rutland's suggestion
---
arch/arm64/mm/dump.c | 26 +++++++++++++++++++-------
1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/mm/dump.c b/arch/arm64/mm/dump.c
index f0f0be7..bb36649 100644
--- a/arch/arm64/mm/dump.c
+++ b/arch/arm64/mm/dump.c
@@ -50,6 +50,18 @@ static const struct addr_marker address_markers[] = {
{ -1, NULL },
};

+#define pt_dump_seq_printf(m, fmt, args...) \
+({ \
+ if (m) \
+ seq_printf(m, fmt, ##args); \
+})
+
+#define pt_dump_seq_puts(m, fmt) \
+({ \
+ if (m) \
+ seq_printf(m, fmt); \
+})
+
/*
* The page dumper groups page table entries of the same type into a single
* description. It uses pg_state to track the range information while
@@ -186,7 +198,7 @@ static void dump_prot(struct pg_state *st, const struct prot_bits *bits,
s = bits->clear;

if (s)
- seq_printf(st->seq, " %s", s);
+ pt_dump_seq_printf(st->seq, " %s", s);
}
}

@@ -200,14 +212,14 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
st->level = level;
st->current_prot = prot;
st->start_address = addr;
- seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
} else if (prot != st->current_prot || level != st->level ||
addr >= st->marker[1].start_address) {
const char *unit = units;
unsigned long delta;

if (st->current_prot) {
- seq_printf(st->seq, "0x%016lx-0x%016lx ",
+ pt_dump_seq_printf(st->seq, "0x%016lx-0x%016lx ",
st->start_address, addr);

delta = (addr - st->start_address) >> 10;
@@ -215,17 +227,17 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,
delta >>= 10;
unit++;
}
- seq_printf(st->seq, "%9lu%c %s", delta, *unit,
+ pt_dump_seq_printf(st->seq, "%9lu%c %s", delta, *unit,
pg_level[st->level].name);
if (pg_level[st->level].bits)
dump_prot(st, pg_level[st->level].bits,
pg_level[st->level].num);
- seq_puts(st->seq, "\n");
+ pt_dump_seq_puts(st->seq, "\n");
}

if (addr >= st->marker[1].start_address) {
st->marker++;
- seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
}

st->start_address = addr;
@@ -235,7 +247,7 @@ static void note_page(struct pg_state *st, unsigned long addr, unsigned level,

if (addr >= st->marker[1].start_address) {
st->marker++;
- seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
+ pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
}

}
--
2.7.4