[glibc/rearnsha/mte-v4.0] linux: Add compatibility definitions to sys/prctl.h for MTE

[Richard Earnshaw]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=fd2892858bf444e1d5ca7a5f3490a6a47eed2ace

commit fd2892858bf444e1d5ca7a5f3490a6a47eed2ace
Author: Richard Earnshaw <rearnsha@arm.com>
Date:   Fri Dec 18 19:00:49 2020 +0000

    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:
---
 sysdeps/unix/sysv/linux/sys/prctl.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/sysdeps/unix/sysv/linux/sys/prctl.h b/sysdeps/unix/sysv/linux/sys/prctl.h
index 7f748ebeeb..4d01379c23 100644
--- 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.  */