From: Sven Schnelle <svens@stackframe.org>
Date: Fri, 15 Oct 2021 19:49:23 +0000 (+0200)
Subject: parisc/kgdb: add kgdb_roundup() to make kgdb work with idle polling
X-Git-Tag: accepted/tizen/unified/20230118.172025~5746
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=ad04ebbe715c97d80528137ca8a18b1291f0feda;p=platform%2Fkernel%2Flinux-rpi.git

parisc/kgdb: add kgdb_roundup() to make kgdb work with idle polling

[ Upstream commit 66e29fcda1824f0427966fbee2bd2c85bf362c82 ]

With idle polling, IPIs are not sent when a CPU idle, but queued
and run later from do_idle(). The default kgdb_call_nmi_hook()
implementation gets the pointer to struct pt_regs from get_irq_reqs(),
which doesn't work in that case because it was not called from the
IPI interrupt handler. Fix it by defining our own kgdb_roundup()
function which sents an IPI_ENTER_KGDB. When that IPI is received
on the target CPU kgdb_nmicallback() is called.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/arch/parisc/kernel/smp.c b/arch/parisc/kernel/smp.c
index 1405b603..cf92ece 100644
--- a/arch/parisc/kernel/smp.c
+++ b/arch/parisc/kernel/smp.c
@@ -29,6 +29,7 @@
 #include <linux/bitops.h>
 #include <linux/ftrace.h>
 #include <linux/cpu.h>
+#include <linux/kgdb.h>
 
 #include <linux/atomic.h>
 #include <asm/current.h>
@@ -69,7 +70,10 @@ enum ipi_message_type {
 	IPI_CALL_FUNC,
 	IPI_CPU_START,
 	IPI_CPU_STOP,
-	IPI_CPU_TEST
+	IPI_CPU_TEST,
+#ifdef CONFIG_KGDB
+	IPI_ENTER_KGDB,
+#endif
 };
 
 
@@ -167,7 +171,12 @@ ipi_interrupt(int irq, void *dev_id)
 			case IPI_CPU_TEST:
 				smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
 				break;
-
+#ifdef CONFIG_KGDB
+			case IPI_ENTER_KGDB:
+				smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu);
+				kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+				break;
+#endif
 			default:
 				printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
 					this_cpu, which);
@@ -226,6 +235,12 @@ send_IPI_allbutself(enum ipi_message_type op)
 	}
 }
 
+#ifdef CONFIG_KGDB
+void kgdb_roundup_cpus(void)
+{
+	send_IPI_allbutself(IPI_ENTER_KGDB);
+}
+#endif
 
 inline void 
 smp_send_stop(void)	{ send_IPI_allbutself(IPI_CPU_STOP); }