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, 29 insertions, 0 deletions

diff --git a/arch/powerpc/boot/treeboot-ebony.c b/arch/powerpc/boot/treeboot-ebony.c
new file mode 100644
index 000000000..332e28659
--- /dev/null
+++ b/arch/powerpc/boot/treeboot-ebony.c
@@ -0,0 +1,29 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Old U-boot compatibility for Ebony
+ *
+ * Author: David Gibson <david@gibson.dropbear.id.au>
+ *
+ * Copyright 2007 David Gibson, IBM Corporatio.
+ *   Based on cuboot-83xx.c, which is:
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ */
+
+#include "ops.h"
+#include "stdio.h"
+#include "44x.h"
+
+BSS_STACK(4096);
+
+#define OPENBIOS_MAC_BASE	0xfffffe0c
+#define OPENBIOS_MAC_OFFSET	0xc
+
+void platform_init(void)
+{
+	unsigned long end_of_ram = 0x8000000;
+	unsigned long avail_ram = end_of_ram - (unsigned long)_end;
+
+	simple_alloc_init(_end, avail_ram, 32, 64);
+	ebony_init((u8 *)OPENBIOS_MAC_BASE,
+		   (u8 *)(OPENBIOS_MAC_BASE + OPENBIOS_MAC_OFFSET));
+}