@@ -17,13 +17,15 @@ this byte for application use.
 Passing tagged addresses to the kernel
 --------------------------------------
 
-All interpretation of userspace memory addresses by the kernel assumes
-an address tag of 0x00.
+The kernel supports tags in pointer arguments (including pointers in
+structures) of syscalls, however such pointers must point to memory ranges
+obtained by anonymous mmap() or brk().
 
-This includes, but is not limited to, addresses found in:
+The kernel supports tags in user fault addresses. However the fault_address
+field in the sigcontext struct will contain an untagged address.
 
- - pointer arguments to system calls, including pointers in structures
-   passed to system calls,
+All other interpretations of userspace memory addresses by the kernel
+assume an address tag of 0x00, in particular:
 
  - the stack pointer (sp), e.g. when interpreting it to deliver a
    signal,

@@ -33,11 +35,7 @@ This includes, but is not limited to, addresses found in:
 
 Using non-zero address tags in any of these locations may result in an
 error code being returned, a (fatal) signal being raised, or other modes
-of failure.
-
-For these reasons, passing non-zero address tags to the kernel via
-system calls is forbidden, and using a non-zero address tag for sp is
-strongly discouraged.
+of failure. Using a non-zero address tag for sp is strongly discouraged.
 
 Programs maintaining a frame pointer and frame records that use non-zero
 address tags may suffer impaired or inaccurate debug and profiling