Index: elf.5
===================================================================
--- elf.5	(revision 359244)
+++ elf.5	(working copy)
@@ -1277,25 +1277,50 @@
 stored into the relocatable field.
 .El
 .Ss Note Section
-ELF note sections consist of entries with the following format.
-.Bl -column -offset indent "Field" "Size" "Description"
-.It Sy Field Ta Sy Size Ta Sy Description
-.It namesz   Ta 32 bits Ta Size of "name"
-.It descsz   Ta 32 bits Ta Size of "desc"
-.It type     Ta 32 bits Ta OS-dependent note type
-.It name     Ta namesz  Ta Null-terminated originator name
-.It desc     Ta descsz  Ta OS-dependent note data
+ELF note sections consist of entries with the following format:
+.Bl -column -offset indent "namesz" "32 bits" "Null-terminated originator name"
+.Sy Field Ta Sy Size Ta Sy Description
+.It Em namesz   Ta 32 bits Ta Size of "name"
+.It Em descsz   Ta 32 bits Ta Size of "desc"
+.It Em type     Ta 32 bits Ta OS-dependent note type
+.It Em name     Ta Em namesz  Ta Null-terminated originator name
+.It Em desc     Ta Em descsz  Ta OS-dependent note data
 .El
 .Pp
 The
-.Sy name
+.Em name
 and
-.Sy desc
+.Em desc
 fields are padded to ensure 4-byte alignemnt.
-.Sy namesz
+.Em namesz
 and
-.Sy descsz
+.Em descsz
 specify the unpadded length.
+.Pp
+.Fx defines the following ELF note types
+.Po with corresponding interpretation of
+.Em desc Pc :
+.Bl -tag -width 4n
+.It Dv NT_FREEBSD_ABI_TAG Pq Value: 1
+Indicates the OS ABI version in a form of a 32-bit integer containing expected
+ABI version
+.Po i.e.,
+.Dv __FreeBSD_version Pc .
+.It Dv NT_FREEBSD_NOINIT_TAG Pq Value: 2
+Indicates that crt does not call init.
+.Em desc
+is ignored.
+.It Dv NT_FREEBSD_ARCH_TAG Pq Value: 3
+.It Dv NT_FREEBSD_FEATURE_CTL Pq Value: 4
+Contains a bitmask of mitigations and features to enable:
+.Bl -column "NT_FREEBSD_FCTL_PROTMAX_DISABLE" "0x00" "Disable implicit PROT_MAX"
+.Sy Name                         Ta Sy Value Ta Sy Description
+.It NT_FREEBSD_FCTL_ASLR_DISABLE    Ta 0x01     Ta Disable ASLR
+.It NT_FREEBSD_FCTL_PROTMAX_DISABLE Ta 0x02     Ta Disable implicit PROT_MAX
+.It NT_FREEBSD_FCTL_STKGAP_DISABLE  Ta 0x04     Ta Disable stack gap
+.It NT_FREEBSD_FCTL_WXNEEDED        Ta 0x08     Ta Binary makes W+X mappings
+.El
+.El
 .Sh SEE ALSO
 .Xr as 1 ,
 .Xr gdb 1 ,