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, 47 insertions, 0 deletions

diff --git a/arch/powerpc/boot/of.h b/arch/powerpc/boot/of.h
new file mode 100644
index 000000000..31b2f5dfd
--- /dev/null
+++ b/arch/powerpc/boot/of.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _PPC_BOOT_OF_H_
+#define _PPC_BOOT_OF_H_
+
+#include "swab.h"
+
+typedef void *phandle;
+typedef u32 ihandle;
+
+void of_init(void *promptr);
+int of_call_prom(const char *service, int nargs, int nret, ...);
+unsigned int of_claim(unsigned long virt, unsigned long size,
+	unsigned long align);
+void *of_vmlinux_alloc(unsigned long size);
+void of_exit(void);
+void *of_finddevice(const char *name);
+int of_getprop(const void *phandle, const char *name, void *buf,
+	       const int buflen);
+int of_setprop(const void *phandle, const char *name, const void *buf,
+	       const int buflen);
+
+/* Console functions */
+void of_console_init(void);
+
+typedef u16			__be16;
+typedef u32			__be32;
+typedef u64			__be64;
+
+#ifdef __LITTLE_ENDIAN__
+#define cpu_to_be16(x) swab16(x)
+#define be16_to_cpu(x) swab16(x)
+#define cpu_to_be32(x) swab32(x)
+#define be32_to_cpu(x) swab32(x)
+#define cpu_to_be64(x) swab64(x)
+#define be64_to_cpu(x) swab64(x)
+#else
+#define cpu_to_be16(x) (x)
+#define be16_to_cpu(x) (x)
+#define cpu_to_be32(x) (x)
+#define be32_to_cpu(x) (x)
+#define cpu_to_be64(x) (x)
+#define be64_to_cpu(x) (x)
+#endif
+
+#define PROM_ERROR (-1u)
+
+#endif /* _PPC_BOOT_OF_H_ */