To take advantage of the hardware pipeline implementation of AES-NI
instructions. CTR mode cryption is implemented in ASM to schedule
multiple AES-NI instructions one after another. This way, some latency
of AES-NI instruction can be eliminated.
Performance testing based on dm-crypt should 50% reduction of
ecryption/decryption time.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When renaming kernel_fpu_using to irq_fpu_usable, the semantics of the
function is changed too, from mesuring whether kernel is using FPU,
that is, the FPU is NOT available, to measuring whether FPU is usable,
that is, the FPU is available.
But the usage of irq_fpu_usable in aesni-intel_glue.c is not changed
accordingly. This patch fixes this.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (22 commits)
x86: Fix code patching for paravirt-alternatives on 486
x86, msr: change msr-reg.o to obj-y, and export its symbols
x86: Use hard_smp_processor_id() to get apic id for AMD K8 cpus
x86, sched: Workaround broken sched domain creation for AMD Magny-Cours
x86, mcheck: Use correct cpumask for shared bank4
x86, cacheinfo: Fixup L3 cache information for AMD multi-node processors
x86: Fix CPU llc_shared_map information for AMD Magny-Cours
x86, msr: Fix msr-reg.S compilation with gas 2.16.1, on 32-bit too
x86: Move kernel_fpu_using to irq_fpu_usable in asm/i387.h
x86, msr: fix msr-reg.S compilation with gas 2.16.1
x86, msr: Export the register-setting MSR functions via /dev/*/msr
x86, msr: Create _on_cpu helpers for {rw,wr}msr_safe_regs()
x86, msr: Have the _safe MSR functions return -EIO, not -EFAULT
x86, msr: CFI annotations, cleanups for msr-reg.S
x86, asm: Make _ASM_EXTABLE() usable from assembly code
x86, asm: Add 32-bit versions of the combined CFI macros
x86, AMD: Disable wrongly set X86_FEATURE_LAHF_LM CPUID bit
x86, msr: Rewrite AMD rd/wrmsr variants
x86, msr: Add rd/wrmsr interfaces with preset registers
x86: add specific support for Intel Atom architecture
...
This function measures whether the FPU/SSE state can be touched in
interrupt context. If the interrupted code is in user space or has no
valid FPU/SSE context (CR0.TS == 1), FPU/SSE state can be used in IRQ
or soft_irq context too.
This is used by AES-NI accelerated AES implementation and PCLMULQDQ
accelerated GHASH implementation.
v3:
- Renamed to irq_fpu_usable to reflect the purpose of the function.
v2:
- Renamed to irq_is_fpu_using to reflect the real situation.
Signed-off-by: Huang Ying <ying.huang@intel.com>
CC: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
When the aes-intel module is loaded on a system that does not have the
AES instructions, it prints
Intel AES-NI instructions are not detected.
at level KERN_ERR. Since aes-intel is aliased to "aes" it will be tried
whenever anything uses AES and spam the console. This doesn't match
existing practice for how to handle "no hardware" when initializing a
module, so downgrade the message to KERN_INFO.
Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Because AES-NI instructions will touch XMM state, corresponding code
must be enclosed within kernel_fpu_begin/end, which used
preempt_disable/enable. So sleep should be prevented between
kernel_fpu_begin/end.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Because kernel_fpu_begin() and kernel_fpu_end() operations are too
slow, the performance gain of general mode implementation + aes-aesni
is almost all compensated.
The AES-NI support for more modes are implemented as follow:
- Add a new AES algorithm implementation named __aes-aesni without
kernel_fpu_begin/end()
- Use fpu(<mode>(AES)) to provide kenrel_fpu_begin/end() invoking
- Add <mode>(AES) ablkcipher, which uses cryptd(fpu(<mode>(AES))) to
defer cryption to cryptd context in soft_irq context.
Now the ctr, lrw, pcbc and xts support are added.
Performance testing based on dm-crypt shows that cryption time can be
reduced to 50% of general mode implementation + aes-aesni implementation.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Intel AES-NI is a new set of Single Instruction Multiple Data (SIMD)
instructions that are going to be introduced in the next generation of
Intel processor, as of 2009. These instructions enable fast and secure
data encryption and decryption, using the Advanced Encryption Standard
(AES), defined by FIPS Publication number 197. The architecture
introduces six instructions that offer full hardware support for
AES. Four of them support high performance data encryption and
decryption, and the other two instructions support the AES key
expansion procedure.
The white paper can be downloaded from:
http://softwarecommunity.intel.com/isn/downloads/intelavx/AES-Instructions-Set_WP.pdf
AES may be used in soft_irq context, but MMX/SSE context can not be
touched safely in soft_irq context. So in_interrupt() is checked, if
in IRQ or soft_irq context, the general x86_64 implementation are used
instead.
Signed-off-by: Huang Ying <ying.huang@intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
