From d73341112da556fe0b0cea75520774b74ee4112e Mon Sep 17 00:00:00 2001
From: Daniele Lacamera <dan@danielinux.net>
Date: Wed, 10 Apr 2024 09:58:19 +0200
Subject: [PATCH 1/2] Anti-glitch armor: Added clobbers to assembly

---
 include/image.h | 220 ++++++++++++++++++++++++------------------------
 1 file changed, 110 insertions(+), 110 deletions(-)

diff --git a/include/image.h b/include/image.h
index 5cd397bb1..c168045d1 100644
--- a/include/image.h
+++ b/include/image.h
@@ -127,13 +127,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
  */
 #define PART_SANITY_CHECK(p) \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading hdr_ok flag, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->hdr_ok)); \
+    asm volatile("mov r2, %0" ::"r"((p)->hdr_ok):"r2"); \
     asm volatile("cmp r2, #1"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, #1"); \
@@ -143,13 +143,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r2, #1"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading hdr_ok flag, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->sha_ok)); \
+    asm volatile("mov r2, %0" ::"r"((p)->sha_ok):"r2"); \
     asm volatile("cmp r2, #1"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, #1"); \
@@ -159,13 +159,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r2, #1"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading signature_ok flag, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->signature_ok)); \
+    asm volatile("mov r2, %0" ::"r"((p)->signature_ok):"r2"); \
     asm volatile("cmp r2, #1"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, #1"); \
@@ -181,7 +181,7 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r2, #0"); \
     asm volatile("mov r2, #0"); \
     /* Loading ~(signature_ok) flag, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->not_signature_ok)); \
+    asm volatile("mov r2, %0" ::"r"((p)->not_signature_ok):"r2"); \
     asm volatile("cmp r2, #0xFFFFFFFE"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, #0xFFFFFFFE"); \
@@ -191,14 +191,14 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r2, #0xFFFFFFFE"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading canary value, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED6789)); \
-    asm volatile("mov r0, %0" ::"r"(0xFEED6789)); \
+    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED6789):"r2"); \
+    asm volatile("mov r0, %0" ::"r"(0xFEED6789):"r0"); \
     asm volatile("cmp r2, r0"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, r0"); \
@@ -208,14 +208,14 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r2, r0"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading canary value, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED4567)); \
-    asm volatile("mov r0, %0" ::"r"(0xFEED4567)); \
+    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED4567):"r2"); \
+    asm volatile("mov r0, %0" ::"r"(0xFEED4567):"r0"); \
     asm volatile("cmp r2, r0"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, r0"); \
@@ -225,14 +225,14 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r2, r0"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
-    asm volatile("mov r2, #0"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
+    asm volatile("mov r2, #0":::"r2"); \
     /* Loading canary value, verifying */ \
-    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED89AB)); \
-    asm volatile("mov r0, %0" ::"r"(0xFEED89AB)); \
+    asm volatile("mov r2, %0" ::"r"((p)->canary_FEED89AB):"r2"); \
+    asm volatile("mov r0, %0" ::"r"(0xFEED89AB):"r0"); \
     asm volatile("cmp r2, r0"); \
     asm volatile("bne ."); \
     asm volatile("cmp r2, r0"); \
@@ -251,16 +251,16 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
 #define RSA_VERIFY_FN(ret,fn,...) \
     { \
         /* Redundant set of r0=0 */ \
-        asm volatile("mov r0, #0"); \
-        asm volatile("mov r0, #0"); \
-        asm volatile("mov r0, #0"); \
+        asm volatile("mov r0, #0":::"r0"); \
+        asm volatile("mov r0, #0":::"r0"); \
+        asm volatile("mov r0, #0":::"r0"); \
         /* Call the function */ \
         int tmp_ret = fn(__VA_ARGS__); \
         ret = -1; \
         /* Redundant set of r2=SHA_DIGEST_SIZE */ \
-        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE)); \
-        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE)); \
-        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE)); \
+        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE):"r2"); \
+        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE):"r2"); \
+        asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE):"r2"); \
         /* Redundant check for fn() return value >= r2 */ \
         asm volatile("cmp r0, r2"); \
         asm volatile("blt nope"); \
@@ -288,9 +288,9 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
         if (!img || !digest)    \
             asm volatile("b hnope"); \
         /* Redundant set of r0=50*/ \
-        asm volatile("mov r0, #50"); \
-        asm volatile("mov r0, #50"); \
-        asm volatile("mov r0, #50"); \
+        asm volatile("mov r0, #50":::"r0"); \
+        asm volatile("mov r0, #50":::"r0"); \
+        asm volatile("mov r0, #50":::"r0"); \
         compare_res = XMEMCMP(digest, img->sha_hash, WOLFBOOT_SHA_DIGEST_SIZE); \
         /* Redundant checks that ensure the function actually returned 0 */ \
         asm volatile("cmp r0, #0"); \
@@ -330,9 +330,9 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
  */
 #define VERIFY_FN(img,p_res,fn,...) \
     /* Redundant set of r0=50*/ \
-    asm volatile("mov r0, #50"); \
-    asm volatile("mov r0, #50"); \
-    asm volatile("mov r0, #50"); \
+    asm volatile("mov r0, #50":::"r0"); \
+    asm volatile("mov r0, #50":::"r0"); \
+    asm volatile("mov r0, #50":::"r0"); \
     /* Call the verify function */ \
     fn(__VA_ARGS__); \
     /* Redundant checks that ensure the function actually returned 0 */ \
@@ -384,19 +384,19 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Stash the registry values */ \
     asm volatile("push {r4, r5, r6, r7}"); \
     /* Redundant initialization with 'failure' values */ \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r4, #1"); \
-    asm volatile("mov r5, #0"); \
-    asm volatile("mov r6, #2"); \
-    asm volatile("mov r7, #0"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r4, #1"); \
-    asm volatile("mov r5, #0"); \
-    asm volatile("mov r6, #2"); \
-    asm volatile("mov r7, #0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r4, #1":::"r4"); \
+    asm volatile("mov r5, #0":::"r5"); \
+    asm volatile("mov r6, #2":::"r6"); \
+    asm volatile("mov r7, #0":::"r7"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r4, #1":::"r4"); \
+    asm volatile("mov r5, #0":::"r5"); \
+    asm volatile("mov r6, #2":::"r6"); \
+    asm volatile("mov r7, #0":::"r7"); \
     /* Read the fb_ok flag, jump to end_check  \
      * if proven fb_ok == 1 */ \
-    asm volatile("mov r0, %0" ::"r"(fb_ok)); \
+    asm volatile("mov r0, %0" ::"r"(fb_ok):"r0"); \
     asm volatile("cmp r0, #1"); \
     asm volatile("bne do_check"); \
     asm volatile("cmp r0, #1"); \
@@ -407,20 +407,20 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Do the actual version check: */ \
     asm volatile("do_check:"); \
     /* Read update versions to reg r5 and r7 */ \
-    asm volatile("mov r0, #1"); \
-    asm volatile("mov r0, #1"); \
-    asm volatile("mov r0, #1"); \
+    asm volatile("mov r0, #1":::"r0"); \
+    asm volatile("mov r0, #1":::"r0"); \
+    asm volatile("mov r0, #1":::"r0"); \
     asm volatile("bl wolfBoot_get_image_version"); \
-    asm volatile("mov r5, r0"); \
-    asm volatile("mov r5, r0"); \
-    asm volatile("mov r5, r0"); \
-    asm volatile("mov r0, #1"); \
-    asm volatile("mov r0, #1"); \
-    asm volatile("mov r0, #1"); \
+    asm volatile("mov r5, r0":::"r5"); \
+    asm volatile("mov r5, r0":::"r5"); \
+    asm volatile("mov r5, r0":::"r5"); \
+    asm volatile("mov r0, #1":::"r0"); \
+    asm volatile("mov r0, #1":::"r0"); \
+    asm volatile("mov r0, #1":::"r0"); \
     asm volatile("bl wolfBoot_get_image_version"); \
-    asm volatile("mov r7, r0"); \
-    asm volatile("mov r7, r0"); \
-    asm volatile("mov r7, r0"); \
+    asm volatile("mov r7, r0":::"r7"); \
+    asm volatile("mov r7, r0":::"r7"); \
+    asm volatile("mov r7, r0":::"r7"); \
     /* Compare r5 and r7, if not equal, something went very wrong, */ \
     asm volatile("cmp r5, r7"); \
     asm volatile("bne ."); \
@@ -431,20 +431,20 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("cmp r5, r7"); \
     asm volatile("bne .-12"); \
     /* Read current versions to reg r4 and r6 */ \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
     asm volatile("bl wolfBoot_get_image_version"); \
-    asm volatile("mov r4, r0"); \
-    asm volatile("mov r4, r0"); \
-    asm volatile("mov r4, r0"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
+    asm volatile("mov r4, r0":::"r4"); \
+    asm volatile("mov r4, r0":::"r4"); \
+    asm volatile("mov r4, r0":::"r4"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
     asm volatile("bl wolfBoot_get_image_version"); \
-    asm volatile("mov r6, r0"); \
-    asm volatile("mov r6, r0"); \
-    asm volatile("mov r6, r0"); \
+    asm volatile("mov r6, r0":::"r6"); \
+    asm volatile("mov r6, r0":::"r6"); \
+    asm volatile("mov r6, r0":::"r6"); \
     asm volatile("cmp r4, r6"); \
     asm volatile("bne ."); \
     asm volatile("cmp r4, r6"); \
@@ -453,9 +453,9 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("bne .-8"); \
     asm volatile("cmp r4, r6"); \
     asm volatile("bne .-12"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
-    asm volatile("mov r0, #0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
+    asm volatile("mov r0, #0":::"r0"); \
     /* Compare the two versions in registries */ \
     asm volatile("cmp r4, r5"); \
     asm volatile("bge ."); \
@@ -467,34 +467,34 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("bge .-12"); \
     asm volatile("end_check:"); \
     /* Restore previously saved registry values */ \
-    asm volatile("pop {r4, r5, r6, r7}")
+    asm volatile("pop {r4, r5, r6, r7}":::"r4", "r5", "r6", "r7")
 
 #define CONFIRM_MASK_VALID(id, mask) \
-    asm volatile("mov r1, %0" :: "r"(id));  \
+    asm volatile("mov r1, %0" :: "r"(id):"r1");  \
     /* id &= 0x0F */ \
-    asm volatile("and.w r1, r1, #15"); \
-    asm volatile("mov r0, %0" :: "r"(mask)); \
-    asm volatile("movs r2, #1"); \
-    asm volatile("lsls r2, r1"); \
-    asm volatile("ands r2, r0"); \
-    asm volatile("movs r0, #1"); \
-    asm volatile("lsls r0, r1"); \
+    asm volatile("and.w r1, r1, #15":::"r1"); \
+    asm volatile("mov r0, %0" :: "r"(mask):"r0"); \
+    asm volatile("movs r2, #1":::"r2"); \
+    asm volatile("lsls r2, r1":::"r2"); \
+    asm volatile("ands r2, r0":::"r2"); \
+    asm volatile("movs r0, #1":::"r0"); \
+    asm volatile("lsls r0, r1":::"r0"); \
     asm volatile("cmp r0, r2"); \
     asm volatile("bne ."); \
     asm volatile("mov r0, %0" :: "r"(mask)); \
-    asm volatile("movs r2, #1"); \
-    asm volatile("lsls r2, r1"); \
-    asm volatile("ands r2, r0"); \
-    asm volatile("movs r0, #1"); \
-    asm volatile("lsls r0, r1"); \
+    asm volatile("movs r2, #1":::"r2"); \
+    asm volatile("lsls r2, r1":::"r2"); \
+    asm volatile("ands r2, r0":::"r2"); \
+    asm volatile("movs r0, #1":::"r0"); \
+    asm volatile("lsls r0, r1":::"r0"); \
     asm volatile("cmp r0, r2"); \
     asm volatile("bne ."); \
-    asm volatile("mov r0, %0" :: "r"(mask)); \
-    asm volatile("movs r2, #1"); \
-    asm volatile("lsls r2, r1"); \
-    asm volatile("ands r2, r0"); \
-    asm volatile("movs r0, #1"); \
-    asm volatile("lsls r0, r1"); \
+    asm volatile("mov r0, %0" :: "r"(mask):"r0"); \
+    asm volatile("movs r2, #1":::"r2"); \
+    asm volatile("lsls r2, r1":::"r2"); \
+    asm volatile("ands r2, r0":::"r2"); \
+    asm volatile("movs r0, #1":::"r0"); \
+    asm volatile("lsls r0, r1":::"r0"); \
     asm volatile("cmp r0, r2"); \
     asm volatile("bne ."); \
 

From 92f630ad3c9a698532336592c049f3402f8f35a2 Mon Sep 17 00:00:00 2001
From: Daniele Lacamera <dan@danielinux.net>
Date: Thu, 11 Apr 2024 12:39:12 +0200
Subject: [PATCH 2/2] Added "cc" clobbers

---
 include/image.h | 152 ++++++++++++++++++++++++------------------------
 1 file changed, 76 insertions(+), 76 deletions(-)

diff --git a/include/image.h b/include/image.h
index c168045d1..1cc8f2a7d 100644
--- a/include/image.h
+++ b/include/image.h
@@ -134,13 +134,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r2, #0":::"r2"); \
     /* Loading hdr_ok flag, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->hdr_ok):"r2"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0":::"r2"); \
@@ -150,13 +150,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r2, #0":::"r2"); \
     /* Loading hdr_ok flag, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->sha_ok):"r2"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0":::"r2"); \
@@ -166,13 +166,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r2, #0":::"r2"); \
     /* Loading signature_ok flag, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->signature_ok):"r2"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0"); \
@@ -182,13 +182,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r2, #0"); \
     /* Loading ~(signature_ok) flag, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->not_signature_ok):"r2"); \
-    asm volatile("cmp r2, #0xFFFFFFFE"); \
+    asm volatile("cmp r2, #0xFFFFFFFE":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, #0xFFFFFFFE"); \
+    asm volatile("cmp r2, #0xFFFFFFFE":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, #0xFFFFFFFE"); \
+    asm volatile("cmp r2, #0xFFFFFFFE":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, #0xFFFFFFFE"); \
+    asm volatile("cmp r2, #0xFFFFFFFE":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0":::"r2"); \
@@ -199,13 +199,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Loading canary value, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->canary_FEED6789):"r2"); \
     asm volatile("mov r0, %0" ::"r"(0xFEED6789):"r0"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0":::"r2"); \
@@ -216,13 +216,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Loading canary value, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->canary_FEED4567):"r2"); \
     asm volatile("mov r0, %0" ::"r"(0xFEED4567):"r0"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-12"); \
     /* Redundant set of r2=0 */ \
     asm volatile("mov r2, #0":::"r2"); \
@@ -233,13 +233,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Loading canary value, verifying */ \
     asm volatile("mov r2, %0" ::"r"((p)->canary_FEED89AB):"r2"); \
     asm volatile("mov r0, %0" ::"r"(0xFEED89AB):"r0"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r2, r0"); \
+    asm volatile("cmp r2, r0":::"cc"); \
     asm volatile("bne .-12")
 
 /**
@@ -262,13 +262,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
         asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE):"r2"); \
         asm volatile("mov r2, %0" ::"r"(WOLFBOOT_SHA_DIGEST_SIZE):"r2"); \
         /* Redundant check for fn() return value >= r2 */ \
-        asm volatile("cmp r0, r2"); \
+        asm volatile("cmp r0, r2":::"cc"); \
         asm volatile("blt nope"); \
-        asm volatile("cmp r0, r2"); \
+        asm volatile("cmp r0, r2":::"cc"); \
         asm volatile("blt nope"); \
-        asm volatile("cmp r0, r2"); \
+        asm volatile("cmp r0, r2":::"cc"); \
         asm volatile("blt nope"); \
-        asm volatile("cmp r0, r2"); \
+        asm volatile("cmp r0, r2":::"cc"); \
         asm volatile("blt nope"); \
         /* Return value is set here in case of success */ \
         ret = tmp_ret; \
@@ -293,24 +293,24 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
         asm volatile("mov r0, #50":::"r0"); \
         compare_res = XMEMCMP(digest, img->sha_hash, WOLFBOOT_SHA_DIGEST_SIZE); \
         /* Redundant checks that ensure the function actually returned 0 */ \
+        asm volatile("cmp r0, #0":::"cc"); \
+        asm volatile("bne hnope":::"cc"); \
         asm volatile("cmp r0, #0"); \
+        asm volatile("bne hnope":::"cc"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
-        asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
-        asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
         /* Repeat memcmp call */ \
         compare_res = XMEMCMP(digest, img->sha_hash, WOLFBOOT_SHA_DIGEST_SIZE); \
         /* Redundant checks that ensure the function actually returned 0 */ \
-        asm volatile("cmp r0, #0"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
-        asm volatile("cmp r0, #0"); \
+        asm volatile("cmp r0, #0":::"cc"); \
         asm volatile("bne hnope"); \
         /* Confirm that the signature is OK */ \
         wolfBoot_image_confirm_signature_ok(img); \
@@ -336,26 +336,26 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Call the verify function */ \
     fn(__VA_ARGS__); \
     /* Redundant checks that ensure the function actually returned 0 */ \
-    asm volatile("cmp r0, #0"); \
+    asm volatile("cmp r0, #0":::"cc"); \
     asm volatile("bne nope"); \
-    asm volatile("cmp r0, #0"); \
+    asm volatile("cmp r0, #0":::"cc"); \
     asm volatile("bne nope"); \
-    asm volatile("cmp r0, #0"); \
+    asm volatile("cmp r0, #0":::"cc"); \
     asm volatile("bne nope"); \
-    asm volatile("cmp r0, #0"); \
+    asm volatile("cmp r0, #0":::"cc"); \
     asm volatile("bne nope"); \
     /* Check that res = 1, a few times, reading the value from memory */ \
     asm volatile("ldr r2, [%0]" ::"r"(p_res)); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne nope"); \
     asm volatile("ldr r2, [%0]" ::"r"(p_res)); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne nope"); \
     asm volatile("ldr r2, [%0]" ::"r"(p_res)); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne nope"); \
     asm volatile("ldr r2, [%0]" ::"r"(p_res)); \
-    asm volatile("cmp r2, #1"); \
+    asm volatile("cmp r2, #1":::"cc"); \
     asm volatile("bne nope"); \
     /* Confirm that the signature is OK */ \
     wolfBoot_image_confirm_signature_ok(img); \
@@ -397,11 +397,11 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     /* Read the fb_ok flag, jump to end_check  \
      * if proven fb_ok == 1 */ \
     asm volatile("mov r0, %0" ::"r"(fb_ok):"r0"); \
-    asm volatile("cmp r0, #1"); \
+    asm volatile("cmp r0, #1":::"cc"); \
     asm volatile("bne do_check"); \
-    asm volatile("cmp r0, #1"); \
+    asm volatile("cmp r0, #1":::"cc"); \
     asm volatile("bne do_check"); \
-    asm volatile("cmp r0, #1"); \
+    asm volatile("cmp r0, #1":::"cc"); \
     asm volatile("bne do_check"); \
     asm volatile("b end_check"); \
     /* Do the actual version check: */ \
@@ -422,13 +422,13 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r7, r0":::"r7"); \
     asm volatile("mov r7, r0":::"r7"); \
     /* Compare r5 and r7, if not equal, something went very wrong, */ \
-    asm volatile("cmp r5, r7"); \
+    asm volatile("cmp r5, r7":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r5, r7"); \
+    asm volatile("cmp r5, r7":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r5, r7"); \
+    asm volatile("cmp r5, r7":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r5, r7"); \
+    asm volatile("cmp r5, r7":::"cc"); \
     asm volatile("bne .-12"); \
     /* Read current versions to reg r4 and r6 */ \
     asm volatile("mov r0, #0":::"r0"); \
@@ -445,25 +445,25 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("mov r6, r0":::"r6"); \
     asm volatile("mov r6, r0":::"r6"); \
     asm volatile("mov r6, r0":::"r6"); \
-    asm volatile("cmp r4, r6"); \
+    asm volatile("cmp r4, r6":::"cc"); \
     asm volatile("bne ."); \
-    asm volatile("cmp r4, r6"); \
+    asm volatile("cmp r4, r6":::"cc"); \
     asm volatile("bne .-4"); \
-    asm volatile("cmp r4, r6"); \
+    asm volatile("cmp r4, r6":::"cc"); \
     asm volatile("bne .-8"); \
-    asm volatile("cmp r4, r6"); \
+    asm volatile("cmp r4, r6":::"cc"); \
     asm volatile("bne .-12"); \
     asm volatile("mov r0, #0":::"r0"); \
     asm volatile("mov r0, #0":::"r0"); \
     asm volatile("mov r0, #0":::"r0"); \
     /* Compare the two versions in registries */ \
-    asm volatile("cmp r4, r5"); \
+    asm volatile("cmp r4, r5":::"cc"); \
     asm volatile("bge ."); \
-    asm volatile("cmp r6, r7"); \
+    asm volatile("cmp r6, r7":::"cc"); \
     asm volatile("bge .-4"); \
-    asm volatile("cmp r4, r5"); \
+    asm volatile("cmp r4, r5":::"cc"); \
     asm volatile("bge .-8"); \
-    asm volatile("cmp r6, r7"); \
+    asm volatile("cmp r6, r7":::"cc"); \
     asm volatile("bge .-12"); \
     asm volatile("end_check:"); \
     /* Restore previously saved registry values */ \
@@ -475,27 +475,27 @@ static void __attribute__((noinline)) wolfBoot_image_confirm_signature_ok(
     asm volatile("and.w r1, r1, #15":::"r1"); \
     asm volatile("mov r0, %0" :: "r"(mask):"r0"); \
     asm volatile("movs r2, #1":::"r2"); \
-    asm volatile("lsls r2, r1":::"r2"); \
-    asm volatile("ands r2, r0":::"r2"); \
-    asm volatile("movs r0, #1":::"r0"); \
-    asm volatile("lsls r0, r1":::"r0"); \
+    asm volatile("lsls r2, r1":::"r2","cc"); \
+    asm volatile("ands r2, r0":::"r2","cc"); \
+    asm volatile("movs r0, #1":::"cc"); \
+    asm volatile("lsls r0, r1":::"r0","cc"); \
     asm volatile("cmp r0, r2"); \
     asm volatile("bne ."); \
     asm volatile("mov r0, %0" :: "r"(mask)); \
     asm volatile("movs r2, #1":::"r2"); \
-    asm volatile("lsls r2, r1":::"r2"); \
-    asm volatile("ands r2, r0":::"r2"); \
+    asm volatile("lsls r2, r1":::"r2", "cc"); \
+    asm volatile("ands r2, r0":::"r2", "cc"); \
     asm volatile("movs r0, #1":::"r0"); \
-    asm volatile("lsls r0, r1":::"r0"); \
-    asm volatile("cmp r0, r2"); \
+    asm volatile("lsls r0, r1":::"r0", "cc"); \
+    asm volatile("cmp r0, r2":::"cc"); \
     asm volatile("bne ."); \
     asm volatile("mov r0, %0" :: "r"(mask):"r0"); \
     asm volatile("movs r2, #1":::"r2"); \
-    asm volatile("lsls r2, r1":::"r2"); \
-    asm volatile("ands r2, r0":::"r2"); \
+    asm volatile("lsls r2, r1":::"r2", "cc"); \
+    asm volatile("ands r2, r0":::"r2", "cc"); \
     asm volatile("movs r0, #1":::"r0"); \
-    asm volatile("lsls r0, r1":::"r0"); \
-    asm volatile("cmp r0, r2"); \
+    asm volatile("lsls r0, r1":::"r0", "cc"); \
+    asm volatile("cmp r0, r2":::"cc"); \
     asm volatile("bne ."); \
 
 #else