set_thread_area.2: Minor tweaks to Eugene's changes

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/set_thread_area.2

@@ -48,12 +48,12 @@ allows storing an arbitrary pointer (provided in the
 .B tp
 argument on m68k and in the
 .B addr
-argument on MIPS) in kernel's structure associated with the caller thread
-and then retrieving it via the
+argument on MIPS)
+in the kernel data structure associated with the calling thread;
+this pointer can later be retrieved using
 .BR get_thread_area ()
-syscall (see also
-.I NOTES
-for the information regarding obtaining thread pointer on MIPS).
+(see also NOTES
+for information regarding obtaining the thread pointer on MIPS).
 .PP
 On x86, Linux dedicates three global descriptor table (GDT) entries for
 thread-local storage.
@@ -130,19 +130,19 @@ Since Linux 3.19,
 cannot be used to write non-present segments, 16-bit segments, or code
 segments, although clearing a segment is still acceptable.
 .SH RETURN VALUE
-On x86, these syscalls
+On x86, these system calls
 return 0 on success, and \-1 on failure, with
 .I errno
 set appropriately.
 .PP
 On MIPS and m68k,
 .BR set_thread_area ()
-syscall always returns 0.
+always returns 0.
 On m68k,
 .BR get_thread_area ()
-syscall returns (previously set via
-.BR set_thread_area ())
-thread area pointer value.
+returns the thread area pointer value
+(previously set via
+.BR set_thread_area ()).
 .SH ERRORS
 .TP
 .B EFAULT
@@ -186,8 +186,16 @@ This is not normally a problem, as
 .BR arch_prctl (2)
 is normally used only by 64-bit programs.
 .PP
-On MIPS, in order to obtain thread area pointer, "rdhwr dest, $29" instruction
-can be used; it traps and is handled by kernel.
+On MIPS, the current value of the thread area pointer can be obtained
+using the instruction:
+.PP
+.in +4n
+.EX
+rdhwr dest, $29
+.EE
+.in
+.PP
+This instruction traps and is handled by kernel.
 .SH BUGS
 On 64-bit kernels before Linux 3.19,
 .\" commit e30ab185c490e9a9381385529e0fd32f0a399495