Re: [PATCH] powerpc/ps3: Fix repository.c build failure

GCC fails to build ps3_defconfig with the following errors:

   arch/powerpc/platforms/ps3/repository.c: In function ‘make_first_field.constprop’:
   arch/powerpc/platforms/ps3/repository.c:78:9: error: ‘strnlen’ specified bound 8 exceeds source size 3 [-Werror=stringop-overread]
      78 |         memcpy((char *)&n, text, strnlen(text, sizeof(n)));
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   arch/powerpc/platforms/ps3/repository.c: In function ‘make_first_field.constprop’:
   arch/powerpc/platforms/ps3/repository.c:78:9: error: ‘strnlen’ specified bound 8 exceeds source size 4 [-Werror=stringop-overread]
      78 |         memcpy((char *)&n, text, strnlen(text, sizeof(n)));
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

The current use of strnlen(text, sizeof(n)) triggers -Wstringop-overread
when text is a short string literal that is smaller than sizeof(n), such
as "bi" or "bus". Use strlen(text) instead and clamp the copy length to
sizeof(n) before memcpy().

Drop the redundant char * cast while at it.

Fixes: f94a84a09148 ("powerpc/ps3: refactor strncpy usage")
Cc: stable@vger.kernel.org
Signed-off-by: Thorsten Blum <redacted>
---
  arch/powerpc/platforms/ps3/repository.c | 5 ++++-
  1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/ps3/repository.c b/arch/powerpc/platforms/ps3/repository.c
index b8c030eab138..0cc755ac3e7f 100644
--- a/arch/powerpc/platforms/ps3/repository.c
+++ b/arch/powerpc/platforms/ps3/repository.c

@@ -6,6 +6,8 @@
   *  Copyright 2006 Sony Corp.
   */
  
+#include <linux/minmax.h>
+
  #include <asm/lv1call.h>
  
  #include "platform.h"

@@ -74,8 +76,9 @@ static void _dump_node(unsigned int lpar_id, u64 n1, u64 n2, u64 n3, u64 n4,
  static u64 make_first_field(const char *text, u64 index)
  {
  	u64 n = 0;
+	size_t len = min(strlen(text), sizeof(n));
  
-	memcpy((char *)&n, text, strnlen(text, sizeof(n)));
+	memcpy(&n, text, len);
  	return PS3_VENDOR_ID_NONE + (n >> 32) + index;
  }