x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

The local "root" pointer is a temporary variable used during the device
search. Therefore, refcount related to the search iterators should be cleaned
up after the search is complete.

Use the __free() cleanup macro to ensure the refcount is decremented when the
temporary pointer goes out of scope.

Additionally, increment the refcount when caching a root pointer. This ensures
the in-use refcount is separate from the temporary search refcounting.

Finally, drop the redundant "root = NULL" before the second search loop. The
pci_get_class() iterator always decrements the refcount of its "from"
argument, so the first loop can only fall through with "root" already NULL.

Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching")
Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com
Reported-by: Sashiko <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 62 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip30/ip30-timer.c b/arch/mips/sgi-ip30/ip30-timer.c
new file mode 100644
index 000000000..294e1f7e6
--- /dev/null
+++ b/arch/mips/sgi-ip30/ip30-timer.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ip30-timer.c: Clocksource/clockevent support for the
+ *               HEART chip in SGI Octane (IP30) systems.
+ *
+ * Copyright (C) 2004-2007 Stanislaw Skowronek <skylark@unaligned.org>
+ * Copyright (C) 2009 Johannes Dickgreber <tanzy@gmx.de>
+ * Copyright (C) 2011 Joshua Kinard <linux@kumba.dev>
+ */
+
+#include <linux/clocksource.h>
+#include <linux/cpumask.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/percpu.h>
+#include <linux/sched_clock.h>
+
+#include <asm/time.h>
+#include <asm/cevt-r4k.h>
+#include <asm/sgi/heart.h>
+
+static u64 ip30_heart_counter_read(struct clocksource *cs)
+{
+	return heart_read(&heart_regs->count);
+}
+
+struct clocksource ip30_heart_clocksource = {
+	.name	= "HEART",
+	.rating	= 400,
+	.read	= ip30_heart_counter_read,
+	.mask	= CLOCKSOURCE_MASK(52),
+	.flags	= (CLOCK_SOURCE_IS_CONTINUOUS | CLOCK_SOURCE_VALID_FOR_HRES),
+};
+
+static u64 notrace ip30_heart_read_sched_clock(void)
+{
+	return heart_read(&heart_regs->count);
+}
+
+static void __init ip30_heart_clocksource_init(void)
+{
+	struct clocksource *cs = &ip30_heart_clocksource;
+
+	clocksource_register_hz(cs, HEART_CYCLES_PER_SEC);
+
+	sched_clock_register(ip30_heart_read_sched_clock, 52,
+			     HEART_CYCLES_PER_SEC);
+}
+
+void __init plat_time_init(void)
+{
+	int irq = get_c0_compare_int();
+
+	cp0_timer_irq_installed = 1;
+	irq_set_handler(irq, handle_percpu_devid_irq);
+	irq_set_percpu_devid(irq);
+	WARN_ON(request_percpu_irq(irq, c0_compare_interrupt,
+				   "timer", &mips_clockevent_device));
+	enable_percpu_irq(irq, IRQ_TYPE_NONE);
+
+	ip30_heart_clocksource_init();
+}