image: use portable noinline macro

F/2273

Author: danielinux

include/image.h

@@ -166,7 +166,7 @@ struct wolfBoot_image {
  * With ARMORED setup, the flag is redundant, and the information is wrapped in
  * between canary variables, to mitigate attacks based on memory corruptions.
  */
-static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
+static void NOINLINEFUNCTION wolfBoot_image_confirm_signature_ok(
     struct wolfBoot_image *img)
 {
     img->canary_FEED4567 = 0xFEED4567UL;
@@ -176,7 +176,7 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     img->canary_FEED89AB = 0xFEED89ABUL;
 }
 
-static void __attribute__((noinline)) wolfBoot_image_clear_signature_ok(
+static void NOINLINEFUNCTION wolfBoot_image_clear_signature_ok(
 	struct wolfBoot_image *img)
 {
 	img->canary_FEED4567 = 0xFEED4567UL;

include/wolfboot/wolfboot.h

@@ -83,6 +83,20 @@ extern "C" {
 #  endif
 #endif
 
+#ifndef NOINLINEFUNCTION
+#  if defined(__has_attribute)
+#    if __has_attribute(noinline)
+#      define NOINLINEFUNCTION __attribute__((noinline))
+#    else
+#      define NOINLINEFUNCTION
+#    endif
+#  elif defined(__GNUC__) || defined(__CC_ARM)
+#    define NOINLINEFUNCTION __attribute__((noinline))
+#  else
+#    define NOINLINEFUNCTION
+#  endif
+#endif
+
 
 /* Helpers for memory alignment */
 #ifndef XALIGNED

src/image.c

@@ -58,7 +58,7 @@
 /* Globals */
 static uint8_t digest[WOLFBOOT_SHA_DIGEST_SIZE] XALIGNED(4);
 
-int __attribute__((noinline)) image_CT_compare(
+int NOINLINEFUNCTION image_CT_compare(
     const uint8_t *expected, const uint8_t *actual, uint32_t len)
 {
     uint8_t diff = 0;