commit e6a72b7dae upstream.
ARCv2 optimized memset uses PREFETCHW instruction for prefetching the
next cache line but doesn't ensure that the line is not past the end of
the buffer. PRETECHW changes the line ownership and marks it dirty,
which can cause issues in SMP config when next line was already owned by
other core. Fix the issue by avoiding the PREFETCHW
Some more details:
The current code has 3 logical loops (ignroing the unaligned part)
(a) Big loop for doing aligned 64 bytes per iteration with PREALLOC
(b) Loop for 32 x 2 bytes with PREFETCHW
(c) any left over bytes
loop (a) was already eliding the last 64 bytes, so PREALLOC was
safe. The fix was removing PREFETCW from (b).
Another potential issue (applicable to configs with 32 or 128 byte L1
cache line) is that PREALLOC assumes 64 byte cache line and may not do
the right thing specially for 32b. While it would be easy to adapt,
there are no known configs with those lie sizes, so for now, just
compile out PREALLOC in such cases.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Cc: stable@vger.kernel.org #4.4+
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: rewrote changelog, used asm .macro vs. "C" macro]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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>
There are configurations which may not have LDD/STD
Signed-off-by: Claudiu Zissulescu <claziss@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
