ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls. Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).
We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.
Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code. This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Patch 638591c enabled building the AES assembler code in Thumb2 mode.
However, this code used arithmetic involving PC rather than adr{l}
instructions to generate PC-relative references to the lookup tables,
and this needs to take into account the different PC offset when
running in Thumb mode.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Nicolas Pitre <nico@linaro.org>
Cc: stable@vger.kernel.org
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch fixes aes-armv4.S and sha1-armv4-large.S to work
natively in Thumb. This allows ARM/Thumb interworking workarounds
to be removed.
I also take the opportunity to convert some explicit assembler
directives for exported functions to the standard
ENTRY()/ENDPROC().
For the code itself:
* In sha1_block_data_order, use of TEQ with sp is deprecated in
ARMv7 and not supported in Thumb. For the branches back to
.L_00_15 and .L_40_59, the TEQ is converted to a CMP, under the
assumption that clobbering the C flag here will not cause
incorrect behaviour.
For the first branch back to .L_20_39_or_60_79 the C flag is
important, so sp is moved temporarily into another register so
that TEQ can be used for the comparison.
* In the AES code, most forms of register-indexed addressing with
shifts and rotates are not permitted for loads and stores in
Thumb, so the address calculation is done using a separate
instruction for the Thumb case.
The resulting code is unlikely to be optimally scheduled, but it
should not have a large impact given the overall size of the code.
I haven't run any benchmarks.
Signed-off-by: Dave Martin <dave.martin@linaro.org>
Tested-by: David McCullough <ucdevel@gmail.com> (ARM only)
Acked-by: David McCullough <ucdevel@gmail.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Add assembler versions of AES and SHA1 for ARM platforms. This has provided
up to a 50% improvement in IPsec/TCP throughout for tunnels using AES128/SHA1.
Platform CPU SPeed Endian Before (bps) After (bps) Improvement
IXP425 533 MHz big 11217042 15566294 ~38%
KS8695 166 MHz little 3828549 5795373 ~51%
Signed-off-by: David McCullough <ucdevel@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Russell King