Avoid integer promotion bug in memory functions

Based on: rhboot/gnu-efi@7cfefa0

Co-authored-by: Peter Jones <pjones@redhat.com>
Signed-off-by: Callum Farmer <gmbr3@opensuse.org>

Make.defaults

@@ -260,9 +260,9 @@ CFLAGS  += $(ARCH3264) -g -O2 -Wall -Wextra -Werror \
            -fno-strict-aliasing \
            -ffreestanding -fno-stack-protector
 else
-CFLAGS  += $(ARCH3264) -g -O2 -Wall -Wextra -Wno-pointer-sign -Werror \
+CFLAGS  += $(ARCH3264) -g -O2 -Wall -Wextra -Werror \
            -fno-strict-aliasing \
-           -ffreestanding -fno-stack-protector -fno-stack-check \
+           -ffreestanding -fno-stack-protector \
            $(if $(findstring 0,$(USING_CLANG)),-Wno-error=maybe-uninitialized,) \
            $(if $(findstring 0,$(USING_CLANG)),-fno-merge-all-constants,)
 endif

lib/runtime/efirtlib.c

@@ -30,7 +30,7 @@ RtZeroMem (
     IN UINTN     Size
     )
 {
-    INT8        *pt;
+    UINT8        *pt;
 
     pt = Buffer;
     while (Size--) {
@@ -50,7 +50,7 @@ RtSetMem (
     IN UINT8    Value
     )
 {
-    INT8        *pt;
+    UINT8        *pt;
 
     pt = Buffer;
     while (Size--) {
@@ -70,8 +70,10 @@ RtCopyMem (
     IN UINTN       len
     )
 {
-    CHAR8 *d = (CHAR8*)Dest;
-    CHAR8 *s = (CHAR8*)Src;
+    UINT8 *d, *s;
+
+    d = Dest;
+    s = Src;
 
     if (d == NULL || s == NULL || s == d)
         return;
@@ -118,7 +120,11 @@ RtCompareMem (
     IN UINTN    len
     )
 {
-    CONST CHAR8    *d = Dest, *s = Src;
+    CONST UINT8 *d, *s;
+
+    d = Dest;
+    s = Src;
+
     while (len--) {
         if (*d != *s) {
             return *d - *s;
@@ -157,14 +163,14 @@ Routine Description:
 
 --*/
 {
-    INT32       *g1, *g2, r;
+    UINT32       *g1, *g2, r;
 
     //
     // Compare 32 bits at a time
     //
 
-    g1 = (INT32 *) Guid1;
-    g2 = (INT32 *) Guid2;
+    g1 = (UINT32*)Guid1;
+    g2 = (UINT32*)Guid2;
 
     r  = g1[0] - g2[0];
     r |= g1[1] - g2[1];