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, 97 insertions, 0 deletions

diff --git a/arch/powerpc/boot/zImage.lds.S b/arch/powerpc/boot/zImage.lds.S
new file mode 100644
index 000000000..d65cd55a6
--- /dev/null
+++ b/arch/powerpc/boot/zImage.lds.S
@@ -0,0 +1,97 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#include <asm-generic/vmlinux.lds.h>
+
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
+OUTPUT_ARCH(powerpc:common64)
+#else
+OUTPUT_ARCH(powerpc:common)
+#endif
+ENTRY(_zimage_start)
+EXTERN(_zimage_start)
+SECTIONS
+{
+  .text      :
+  {
+    _start = .;
+    *(.text)
+    *(.fixup)
+    _etext = .;
+  }
+  . = ALIGN(4096);
+  .data    :
+  {
+    *(.rodata*)
+    *(.data*)
+    *(.sdata*)
+#ifndef CONFIG_PPC64_BOOT_WRAPPER
+    *(.got2)
+#endif
+  }
+  .dynsym : { *(.dynsym) }
+  .dynstr : { *(.dynstr) }
+  .dynamic :
+  {
+    __dynamic_start = .;
+    *(.dynamic)
+  }
+
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
+  .got : ALIGN(256)
+  {
+    *(.got .toc)
+  }
+#endif
+
+  .hash : { *(.hash) }
+  .interp : { *(.interp) }
+  .rela.dyn :
+  {
+#ifdef CONFIG_PPC64_BOOT_WRAPPER
+    __rela_dyn_start = .;
+#endif
+    *(.rela*)
+  }
+
+  . = ALIGN(8);
+  .kernel:dtb :
+  {
+    _dtb_start = .;
+    *(.kernel:dtb)
+    _dtb_end = .;
+  }
+
+  . = ALIGN(4096);
+  .kernel:vmlinux.strip :
+  {
+    _vmlinux_start =  .;
+    *(.kernel:vmlinux.strip)
+    _vmlinux_end =  .;
+  }
+
+  . = ALIGN(4096);
+  .kernel:initrd :
+  {
+    _initrd_start =  .;
+    *(.kernel:initrd)
+    _initrd_end =  .;
+  }
+
+  . = ALIGN(4096);
+  .kernel:esm_blob :
+  {
+    _esm_blob_start =  .;
+    *(.kernel:esm_blob)
+    _esm_blob_end =  .;
+  }
+
+  . = ALIGN(4096);
+  .bss       :
+  {
+    _edata  =  .;
+    __bss_start = .;
+    *(.sbss)
+    *(.bss)
+    *(COMMON)
+    _end = . ;
+  }
+}