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, 89 insertions, 0 deletions

diff --git a/arch/m68k/lib/memcpy.c b/arch/m68k/lib/memcpy.c
new file mode 100644
index 000000000..c1e2dfb20
--- /dev/null
+++ b/arch/m68k/lib/memcpy.c
@@ -0,0 +1,89 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/string.h>
+
+void *memcpy(void *to, const void *from, size_t n)
+{
+	void *xto = to;
+	size_t temp;
+
+	if (!n)
+		return xto;
+	if ((long)to & 1) {
+		char *cto = to;
+		const char *cfrom = from;
+		*cto++ = *cfrom++;
+		to = cto;
+		from = cfrom;
+		n--;
+	}
+#if defined(CONFIG_M68000)
+	if ((long)from & 1) {
+		char *cto = to;
+		const char *cfrom = from;
+		for (; n; n--)
+			*cto++ = *cfrom++;
+		return xto;
+	}
+#endif
+	if (n > 2 && (long)to & 2) {
+		short *sto = to;
+		const short *sfrom = from;
+		*sto++ = *sfrom++;
+		to = sto;
+		from = sfrom;
+		n -= 2;
+	}
+	temp = n >> 2;
+	if (temp) {
+		long *lto = to;
+		const long *lfrom = from;
+#if defined(CONFIG_M68000) || defined(CONFIG_COLDFIRE)
+		for (; temp; temp--)
+			*lto++ = *lfrom++;
+#else
+		size_t temp1;
+		asm volatile (
+			"	movel %2,%3\n"
+			"	andw  #7,%3\n"
+			"	lsrl  #3,%2\n"
+			"	negw  %3\n"
+			"	jmp   %%pc@(1f,%3:w:2)\n"
+			"4:	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"	movel %0@+,%1@+\n"
+			"1:	dbra  %2,4b\n"
+			"	clrw  %2\n"
+			"	subql #1,%2\n"
+			"	jpl   4b"
+			: "=a" (lfrom), "=a" (lto), "=d" (temp), "=&d" (temp1)
+			: "0" (lfrom), "1" (lto), "2" (temp));
+#endif
+		to = lto;
+		from = lfrom;
+	}
+	if (n & 2) {
+		short *sto = to;
+		const short *sfrom = from;
+		*sto++ = *sfrom++;
+		to = sto;
+		from = sfrom;
+	}
+	if (n & 1) {
+		char *cto = to;
+		const char *cfrom = from;
+		*cto = *cfrom;
+	}
+	return xto;
+}
+EXPORT_SYMBOL(memcpy);