Subject: [PATCH v3 9/9] powerpc/traps: Add line prefix in show_instructions()

From: Murilo Opsfelder Araujo <[email-masked]>
Date: Tue, 31 Jul 2018 11:50:20 -0300

Remove "Instruction dump:" line by adding a prefix to display current->comm
and current->pid, along with the instructions dump.

The prefix can serve as a glue that links the instructions dump to its
originator, allowing messages to be interleaved in the logs.

Before this patch, a page fault looked like:

  pandafault[10524]: segfault (11) at 100007d0 nip 1000061c lr 7fffbd295100 code 2 in pandafault[10000000+10000]
  Instruction dump:
  4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe
  392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040

After this patch, it looks like:

  pandafault[10850]: segfault (11) at 100007d0 nip 1000061c lr 7fff9f3e5100 code 2 in pandafault[10000000+10000]
  pandafault[10850]: code: 4bfffeec 4bfffee8 3c401002 38427f00 fbe1fff8 f821ffc1 7c3f0b78 3d22fffe
  pandafault[10850]: code: 392988d0 f93f0020 e93f0020 39400048 <99490000> 39200000 7d234b78 383f0040

Signed-off-by: Murilo Opsfelder Araujo <[email-masked]>
---
 arch/powerpc/kernel/process.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index e78799a8855a..d12143e7d8f9 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1265,16 +1265,19 @@ static int instructions_to_print = 16;
 void show_instructions(struct pt_regs *regs)
 {
 	int i;
+	const char *prefix = KERN_INFO "%s[%d]: code: ";
 	unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
 			sizeof(int));
 
-	printk("Instruction dump:");
+	printk(prefix, current->comm, current->pid);
 
 	for (i = 0; i < instructions_to_print; i++) {
 		int instr;
 
-		if (!(i % 8))
+		if (!(i % 8) && (i > 0)) {
 			pr_cont("\n");
+			printk(prefix, current->comm, current->pid);
+		}
 
 #if !defined(CONFIG_BOOKE)
 		/* If executing with the IMMU off, adjust pc rather
-- 
2.17.1