parisc: Fix and improve kernel stack unwinding

This patchset fixes and improves stack unwinding a lot:
1. Show backward stack traces with up to 30 callsites
2. Add callinfo to ENTRY_CFI() such that every assembler function will get an
   entry in the unwind table
3. Use constants instead of numbers in call_on_stack()
4. Do not depend on CONFIG_KALLSYMS to generate backtraces.
5. Speed up backtrace generation

Make sure you have this patch to GNU as installed:
https://sourceware.org/ml/binutils/2018-07/msg00474.html
Without this patch, unwind info in the kernel is often wrong for various
functions.

Signed-off-by: Helge Deller <deller@gmx.de>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/parisc/kernel/process.c b/arch/parisc/kernel/process.c
index b931745815e0..eb39e7e380d7 100644
--- a/arch/parisc/kernel/process.c
+++ b/arch/parisc/kernel/process.c
@@ -302,7 +302,7 @@ get_wchan(struct task_struct *p)
 		ip = info.ip;
 		if (!in_sched_functions(ip))
 			return ip;
-	} while (count++ < 16);
+	} while (count++ < MAX_UNWIND_ENTRIES);
 	return 0;
 }