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, 56 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/ipic.h b/arch/powerpc/sysdev/ipic.h
new file mode 100644
index 000000000..45ab61406
--- /dev/null
+++ b/arch/powerpc/sysdev/ipic.h
@@ -0,0 +1,56 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * IPIC private definitions and structure.
+ *
+ * Maintainer: Kumar Gala <galak@kernel.crashing.org>
+ *
+ * Copyright 2005 Freescale Semiconductor, Inc
+ */
+#ifndef __IPIC_H__
+#define __IPIC_H__
+
+#include <asm/ipic.h>
+
+#define NR_IPIC_INTS 128
+
+/* External IRQS */
+#define IPIC_IRQ_EXT0 48
+#define IPIC_IRQ_EXT1 17
+#define IPIC_IRQ_EXT7 23
+
+/* Default Priority Registers */
+#define IPIC_PRIORITY_DEFAULT 0x05309770
+
+/* System Global Interrupt Configuration Register */
+#define	SICFR_IPSA	0x00010000
+#define	SICFR_IPSB	0x00020000
+#define	SICFR_IPSC	0x00040000
+#define	SICFR_IPSD	0x00080000
+#define	SICFR_MPSA	0x00200000
+#define	SICFR_MPSB	0x00400000
+
+/* System External Interrupt Mask Register */
+#define	SEMSR_SIRQ0	0x00008000
+
+/* System Error Control Register */
+#define SERCR_MCPR	0x00000001
+
+struct ipic {
+	volatile u32 __iomem	*regs;
+
+	/* The remapper for this IPIC */
+	struct irq_domain		*irqhost;
+};
+
+struct ipic_info {
+	u8	ack;		/* pending register offset from base if the irq
+				   supports ack operation */
+	u8	mask;		/* mask register offset from base */
+	u8	prio;		/* priority register offset from base */
+	u8	force;		/* force register offset from base */
+	u8	bit;		/* register bit position (as per doc)
+				   bit mask = 1 << (31 - bit) */
+	u8	prio_mask;	/* priority mask value */
+};
+
+#endif /* __IPIC_H__ */