[PATCH] powerpc/xmon: Allow limiting the size of the paca display

[Michael Ellerman]

The paca display is already more than 24 lines, which can be problematic
if you have an old school 80x24 terminal, or more likely you are on a
virtual terminal which does not scroll for whatever reason.

We'd like to expand the paca display even more, so add a way to limit
the number of lines that are displayed.

This adds a third form of 'dp' which is 'dp # #', where the first number
is the cpu, and the second is the number of lines to display.

Example output:

  5:mon> dp 3 6
  paca for cpu 0x3 @ c00000000fdc0d80:
   possible         = yes
   present          = yes
   online           = yes
   lock_token       = 0x8000            	(0xa)
   paca_index       = 0x3               	(0x8)

Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
---
 arch/powerpc/xmon/xmon.c | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index e599259d84fc..6f44e9c07f34 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -205,6 +205,7 @@ Commands:\n\
 #ifdef CONFIG_PPC64
   "\
   dp[#]	dump paca for current cpu, or cpu #\n\
+  dp##  dump paca for cpu #, only # lines\n\
   dpa	dump paca for all possible cpus\n"
 #endif
   "\
@@ -2070,9 +2071,10 @@ static void xmon_rawdump (unsigned long adrs, long ndump)
 }
 
 #ifdef CONFIG_PPC64
-static void dump_one_paca(int cpu)
+static void dump_one_paca(int cpu, int num_lines)
 {
 	struct paca_struct *p;
+	int i;
 
 	if (setjmp(bus_error_jmp) != 0) {
 		printf("*** Error dumping paca for cpu 0x%x!\n", cpu);
@@ -2090,9 +2092,12 @@ static void dump_one_paca(int cpu)
 	printf(" %-*s = %s\n", 16, "present", cpu_present(cpu) ? "yes" : "no");
 	printf(" %-*s = %s\n", 16, "online", cpu_online(cpu) ? "yes" : "no");
 
+	i = 4; /* We always print the first four lines */
+
 #define DUMP(paca, name, format) \
-	printf(" %-*s = %#-*"format"\t(0x%lx)\n", 16, #name, 18, paca->name, \
-		offsetof(struct paca_struct, name));
+	if (!num_lines || i++ < num_lines)	\
+		printf(" %-*s = %#-*"format"\t(0x%lx)\n", 16, #name, 18, \
+		       paca->name, offsetof(struct paca_struct, name));
 
 	DUMP(p, lock_token, "x");
 	DUMP(p, paca_index, "x");
@@ -2135,7 +2140,7 @@ static void dump_all_pacas(void)
 	}
 
 	for_each_possible_cpu(cpu)
-		dump_one_paca(cpu);
+		dump_one_paca(cpu, 0);
 }
 
 static void dump_pacas(void)
@@ -2151,10 +2156,12 @@ static void dump_pacas(void)
 
 	termch = c;	/* Put c back, it wasn't 'a' */
 
-	if (scanhex(&num))
-		dump_one_paca(num);
-	else
-		dump_one_paca(xmon_owner);
+	if (scanhex(&num)) {
+		unsigned long lines = 0;
+		scanhex(&lines);
+		dump_one_paca(num, lines);
+	} else
+		dump_one_paca(xmon_owner, 0);
 }
 #endif
 
-- 
2.1.4