xen: Add an unsecure Taint type

Define a new Unsecure taint type to be used to signal a system tainted
due to an unsecure configuration or hardware feature/errata.

Signed-off-by: Bertrand Marquis <bertrand.marquis@arm.com>
Reviewed-by: Stefano Stabellini <sstabellini@kernel.org>

xen/common/kernel.c

@@ -326,6 +326,7 @@ unsigned int tainted;
  *  'E' - An error (e.g. a machine check exceptions) has been injected.
  *  'H' - HVM forced emulation prefix is permitted.
  *  'M' - Machine had a machine check experience.
+ *  'U' - Platform is unsecure (usually due to an errata on the platform).
  *
  *      The string is overwritten by the next call to print_taint().
  */
@@ -333,7 +334,8 @@ char *print_tainted(char *str)
 {
     if ( tainted )
     {
-        snprintf(str, TAINT_STRING_MAX_LEN, "Tainted: %c%c%c%c",
+        snprintf(str, TAINT_STRING_MAX_LEN, "Tainted: %c%c%c%c%c",
+                 tainted & TAINT_MACHINE_UNSECURE ? 'U' : ' ',
                  tainted & TAINT_MACHINE_CHECK ? 'M' : ' ',
                  tainted & TAINT_SYNC_CONSOLE ? 'C' : ' ',
                  tainted & TAINT_ERROR_INJECT ? 'E' : ' ',

xen/include/xen/lib.h

@@ -193,6 +193,7 @@ uint64_t muldiv64(uint64_t a, uint32_t b, uint32_t c);
 #define TAINT_MACHINE_CHECK             (1u << 1)
 #define TAINT_ERROR_INJECT              (1u << 2)
 #define TAINT_HVM_FEP                   (1u << 3)
+#define TAINT_MACHINE_UNSECURE          (1u << 4)
 extern unsigned int tainted;
 #define TAINT_STRING_MAX_LEN            20
 extern char *print_tainted(char *str);