linux: Add compatibility definitions to sys/prctl.h for MTE

Older versions of the Linux kernel headers obviously lack support for
memory tagging, but we still want to be able to build in support when
using those (obviously it can't be enabled on such systems).

The linux kernel extensions are made to the platform-independent
header (linux/prctl.h), so this patch takes a similar approach.

diff --git a/sysdeps/unix/sysv/linux/sys/prctl.h b/sysdeps/unix/sysv/linux/sys/prctl.h
index 7f748ebeeb1be862b3fad6794019d2568e17e3e1..4d01379c23761a3e0d12808ac2e18ea8382d3869 100644 (file)
--- a/sysdeps/unix/sysv/linux/sys/prctl.h
+++ b/sysdeps/unix/sysv/linux/sys/prctl.h
@@ -21,6 +21,24 @@
 #include <features.h>
 #include <linux/prctl.h>  /*  The magic values come from here  */
 
+/* Recent extensions to linux which may post-date the kernel headers
+   we're picking up...  */
+
+/* Memory tagging control operations (for AArch64).  */
+#ifndef PR_TAGGED_ADDR_ENABLE
+# define PR_TAGGED_ADDR_ENABLE (1UL << 8)
+#endif
+
+#ifndef PR_MTE_TCF_SHIFT
+# define PR_MTE_TCF_SHIFT      1
+# define PR_MTE_TCF_NONE       (0UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_SYNC       (1UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_ASYNC      (2UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TCF_MASK       (3UL << PR_MTE_TCF_SHIFT)
+# define PR_MTE_TAG_SHIFT      3
+# define PR_MTE_TAG_MASK       (0xffffUL << PR_MTE_TAG_SHIFT)
+#endif
+
 __BEGIN_DECLS
 
 /* Control process execution.  */