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

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@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)