Index: head/lib/libc/gen/auxv.3
===================================================================
--- head/lib/libc/gen/auxv.3
+++ head/lib/libc/gen/auxv.3
@@ -24,7 +24,7 @@
 .\"
 .\" $FreeBSD$
 .\"
-.Dd November 13, 2019
+.Dd November 17, 2019
 .Dt ELF_AUX_INFO 3
 .Os
 .Sh NAME
@@ -44,29 +44,41 @@
 The information is stored into the provided buffer if it will fit.
 The following values, defined in
 .In sys/elf_common.h
-can be requested:
+can be requested (corresponding buffer sizes are specified in parenthesis):
 .Bl -tag -width AT_OSRELDATE
 .It AT_CANARY
-The canary value for SSP.
+The canary value for SSP (arbitrary sized buffer, as many bytes are
+returned as it fits into it, rest is zeroed).
 .It AT_EXECPATH
-The path of executed program.
+The path of executed program
+.Dv (MAXPATHLEN).
 This may not be present if the process was initialized by
 .Xr fexecve 2
 and the namecache no longer contains the file's name.
 .It AT_HWCAP
-CPU / hardware feature flags.
+CPU / hardware feature flags
+.Dv (sizeof(u_long)).
 .It AT_HWCAP2
-CPU / hardware feature flags.
+CPU / hardware feature flags
+.Dv (sizeof(u_long)).
 .It AT_NCPUS
-Number of CPUs.
+Number of CPUs
+.Dv (sizeof(int)).
 .It AT_OSRELDATE
-Kernel OSRELDATE.
+The
+.Dv OSRELDATE
+of the kernel or jail the program is running on
+.Dv (sizeof(int)).
 .It AT_PAGESIZES
-Vector of page sizes.
+Vector of page sizes (arbitrary sized buffer, as many elements of the
+.Dv pagesizes
+array are returned as it fits).
 .It AT_PAGESZ
-Page size in bytes.
+Page size in bytes
+.Dv (sizeof(int)).
 .It AT_TIMEKEEP
-Pointer to VDSO timehands (for library internal use).
+Pointer to VDSO timehands (for library internal use,
+.Dv sizeof(void *)).
 .El
 .Sh RETURN VALUES
 Returns zero on success, or an error number on failure.