kernel-ark/arch/arc/lib/strlen.S
Vineet Gupta 86effd0dc6 ARC: dw2 unwind: enable cfi pseudo ops in string lib
This uses a new set of annoations viz. ENTRY_CFI/END_CFI to enabel cfi
ops generation.

Note that we didn't change the normal ENTRY/EXIT as we don't actually
want unwind info in the trap/exception/interrutp handlers which use
these, as unwinder then gets confused (it keeps recursing vs. stopping).
Semantically these are leaf routines and unwinding should stop when it
hits those routines.

Before
------

    28.52%     1.19%          9929  hackbench  libuClibc-1.0.17.so   [.] __write_nocancel
            |
            ---__write_nocancel
               |--8.95%--EV_Trap
               |           --8.25%--sys_write
               |                     |--3.93%--sock_write_iter
     ...
               |--2.62%--memset   <==== [LEAF entry as no unwind info]
                         ^^^^^^

After
-----

    29.46%     1.24%         13622  hackbench  libuClibc-1.0.17.so   [.] __write_nocancel
            |
            ---__write_nocancel
               |--9.31%--EV_Trap
               |           --8.62%--sys_write
               |                     |--4.17%--sock_write_iter
     ...
               |--6.19%--sys_write
               |           --6.19%--sock_write_iter
               |                     unix_stream_sendmsg
               |                     |--1.62%--sock_alloc_send_pskb
               |                     |--0.89%--sock_def_readable
               |                     |--0.88%--_raw_spin_unlock_irqrestore
               |                     |--0.69%--memset
               |                     |         ^^^^^^     <==== [now in proper callframe]
               |                     |
               |                      --0.52%--skb_copy_datagram_from_iter

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
2016-09-30 14:48:22 -07:00

84 lines
1.4 KiB
ArmAsm

/*
* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/linkage.h>
ENTRY_CFI(strlen)
or r3,r0,7
ld r2,[r3,-7]
ld.a r6,[r3,-3]
mov r4,0x01010101
; uses long immediate
#ifdef __LITTLE_ENDIAN__
asl_s r1,r0,3
btst_s r0,2
asl r7,r4,r1
ror r5,r4
sub r1,r2,r7
bic_s r1,r1,r2
mov.eq r7,r4
sub r12,r6,r7
bic r12,r12,r6
or.eq r12,r12,r1
and r12,r12,r5
brne r12,0,.Learly_end
#else /* BIG ENDIAN */
ror r5,r4
btst_s r0,2
mov_s r1,31
sub3 r7,r1,r0
sub r1,r2,r4
bic_s r1,r1,r2
bmsk r1,r1,r7
sub r12,r6,r4
bic r12,r12,r6
bmsk.ne r12,r12,r7
or.eq r12,r12,r1
and r12,r12,r5
brne r12,0,.Learly_end
#endif /* ENDIAN */
.Loop:
ld_s r2,[r3,4]
ld.a r6,[r3,8]
; stall for load result
sub r1,r2,r4
bic_s r1,r1,r2
sub r12,r6,r4
bic r12,r12,r6
or r12,r12,r1
and r12,r12,r5
breq r12,0,.Loop
.Lend:
and.f r1,r1,r5
sub.ne r3,r3,4
mov.eq r1,r12
#ifdef __LITTLE_ENDIAN__
sub_s r2,r1,1
bic_s r2,r2,r1
norm r1,r2
sub_s r0,r0,3
lsr_s r1,r1,3
sub r0,r3,r0
j_s.d [blink]
sub r0,r0,r1
#else /* BIG ENDIAN */
lsr_s r1,r1,7
mov.eq r2,r6
bic_s r1,r1,r2
norm r1,r1
sub r0,r3,r0
lsr_s r1,r1,3
j_s.d [blink]
add r0,r0,r1
#endif /* ENDIAN */
.Learly_end:
b.d .Lend
sub_s.ne r1,r1,r1
END_CFI(strlen)