memset() is patched after initialisation to activate the
optimised part which uses cache instructions.
Today we have a 'b 2f' to skip the optimised patch, which then gets
replaced by a NOP, implying a useless cycle consumption.
As we have a 'bne 2f' just before, we could use that instruction
for the live patching, hence removing the need to have a
dedicated 'b 2f' to be replaced by a NOP.
This patch changes the 'bne 2f' by a 'b 2f'. During init, that
'b 2f' is then replaced by 'bne 2f'
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
There is no need to extend the set value to an int when the length
is lower than 4 as in that case we only do byte stores.
We can therefore immediately branch to the part handling it.
By separating it from the normal case, we are able to eliminate
a few actions on the destination pointer.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 9445aa1a30 ("ppc: move exports to definitions")
added EXPORT_SYMBOL() for memset() and flush_hash_pages() in
the middle of the functions.
This patch moves them at the end of the two functions.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Commit 694fc88ce2 ("powerpc/string: Implement optimized
memset variants") added memset16(), memset32() and memset64()
for the 64 bits PPC.
On 32 bits, memset64() is not relevant, and as shown below,
the generic version of memset32() gives a good code, so only
memset16() is candidate for an optimised version.
000009c0 <memset32>:
9c0: 2c 05 00 00 cmpwi r5,0
9c4: 39 23 ff fc addi r9,r3,-4
9c8: 4d 82 00 20 beqlr
9cc: 7c a9 03 a6 mtctr r5
9d0: 94 89 00 04 stwu r4,4(r9)
9d4: 42 00 ff fc bdnz 9d0 <memset32+0x10>
9d8: 4e 80 00 20 blr
The last part of memset() handling the not 4-bytes multiples
operates on bytes, making it unsuitable for handling word without
modification. As it would increase memset() complexity, it is
better to implement memset16() from scratch. In addition it
has the advantage of allowing a more optimised memset16() than what
we would have by using the memset() function.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This macro is taken from s390, and allows more flexibility in
changing exception table format.
mpe: Put it in ppc_asm.h and only define one version using
stringinfy_in_c(). Add some empty definitions and headers to keep the
selftests happy.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
generic_memcpy() is only called from copy_32.S, so there's no reason for
it to be global.
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
memset() uses instruction dcbz to speed up clearing by not wasting time
loading cache line with data that will be overwritten.
Some platform like mpc52xx do no have cache active at startup and
can therefore not use memset(). Allthough no part of the code
explicitly uses memset(), GCC may make calls to it.
This patch modifies memset() such that at startup, memset()
unconditionally skip the optimised bloc that uses dcbz instruction.
Once the initial MMU is set up, in machine_init() we patch memset()
by replacing this inconditional jump by a NOP
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
memcpy() uses instruction dcbz to speed up copy by not wasting time
loading cache line with data that will be overwritten.
Some platform like mpc52xx do no have cache active at startup and
can therefore not use memcpy(). Allthough no part of the code
explicitly uses memcpy(), GCC makes calls to it.
This patch modifies memcpy() such that at startup, memcpy()
unconditionally jumps to generic_memcpy() which doesn't use
the dcbz instruction.
Once the initial MMU is set up, in machine_init() we patch memcpy()
by replacing this inconditional jump by a NOP
Reported-by: Michal Sojka <sojkam1@fel.cvut.cz>
Tested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This patch adds a few optimisations in memcpy functions by using
lbzu/stbu instead of lxb/stb and by re-ordering insn inside a loop
to reduce latency due to loading
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
cacheable_memcpy uses dcbz instruction and is more efficient than
memcpy when the destination is in RAM. If the destination is in an
io area, memcpy_toio() is normally used, not memcpy
This patch renames memcpy as generic_memcpy, and renames
cacheable_memcpy as memcpy
On MPC885, we get approximatly 7% increase of the transfer rate
on an FTP reception
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
cacheable_memzero() which has become the new memset() and the old
memset() are quite similar, so just merge them.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
cacheable_memzero uses dcbz instruction and is more efficient than
memset(0) when the destination is in RAM
This patch renames memset as generic_memset, and defines memset
as a prolog to cacheable_memzero. This prolog checks if the byte
to set is 0. If not, it falls back to generic_memcpy()
cacheable_memzero disappears as it is not referenced anywhere anymore
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
This partially reverts
commit 'powerpc: Remove duplicate cacheable_memcpy/memzero functions
("b05ae4ee602b7dc90771408ccf0972e1b3801a35")'
Functions cacheable_memcpy/memzero are more efficient than
memcpy/memset as they use the dcbz instruction which avoids refill
of the cacheline with the data that we will overwrite.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <scottwood@freescale.com>
These functions are only used from one place each. If the cacheable_*
versions really are more efficient, then those changes should be
migrated into the common code instead.
NOTE: The old routines are just flat buggy on kernels that support
hardware with different cacheline sizes.
Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Now that 8xx can fixup dcbX instructions, start using them
where possible like every other PowerPc arch do.
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
This doesn't change any code, just renames things so we consistently
have foo_32.c and foo_64.c where we have separate 32- and 64-bit
versions.
Signed-off-by: Paul Mackerras <paulus@samba.org>
