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, 40 insertions, 0 deletions

diff --git a/arch/arm64/tools/gen-cpucaps.awk b/arch/arm64/tools/gen-cpucaps.awk
new file mode 100755
index 000000000..2f4f61a0a
--- /dev/null
+++ b/arch/arm64/tools/gen-cpucaps.awk
@@ -0,0 +1,40 @@
+#!/bin/awk -f
+# SPDX-License-Identifier: GPL-2.0
+# gen-cpucaps.awk: arm64 cpucaps header generator
+#
+# Usage: awk -f gen-cpucaps.awk cpucaps.txt
+
+# Log an error and terminate
+function fatal(msg) {
+	print "Error at line " NR ": " msg > "/dev/stderr"
+	exit 1
+}
+
+# skip blank lines and comment lines
+/^$/ { next }
+/^#/ { next }
+
+BEGIN {
+	print "#ifndef __ASM_CPUCAP_DEFS_H"
+	print "#define __ASM_CPUCAP_DEFS_H"
+	print ""
+	print "/* Generated file - do not edit */"
+	cap_num = 0
+	print ""
+}
+
+/^[vA-Z0-9_]+$/ {
+	printf("#define ARM64_%-40s\t%d\n", $0, cap_num++)
+	next
+}
+
+END {
+	printf("#define ARM64_NCAPS\t\t\t\t\t%d\n", cap_num)
+	print ""
+	print "#endif /* __ASM_CPUCAP_DEFS_H */"
+}
+
+# Any lines not handled by previous rules are unexpected
+{
+	fatal("unhandled statement")
+}