Re: [PATCH] x86/copy_user_generic: Optimize copy_user_generic with CPU erms feature

[Ingo Molnar <mingo@kernel.org>]

* Fenghua Yu <fenghua.yu@intel.com> wrote:

> From: Fenghua Yu <fenghua.yu@intel.com>
> 
> According to Intel 64 and IA-32 SDM and Optimization Reference Manual, beginning
> with Ivybridge, REG string operation using MOVSB and STOSB can provide both
> flexible and high-performance REG string operations in cases like memory copy.
> Enhancement availability is indicated by CPUID.7.0.EBX[9] (Enhanced REP MOVSB/
> STOSB).
> 
> If CPU erms feature is detected, patch copy_user_generic with enhanced fast
> string version of copy_user_generic.
> 
> A few new macros are defined to reduce duplicate code in ALTERNATIVE and
> ALTERNATIVE_2.
> 
> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
> ---
> checkpatch.pl reports two errors in alternative_call_2() definition. I think
> the errors are invalid and should be ignored:
> ERROR: Macros with complex values should be enclosed in parenthesis
> ERROR: space prohibited before open square bracket '['

ok.

> 
>  arch/x86/include/asm/alternative.h |   74 ++++++++++++++++++++++++++++-------
>  arch/x86/include/asm/uaccess_64.h  |   11 +++++-
>  arch/x86/kernel/x8664_ksyms_64.c   |    1 +
>  3 files changed, 70 insertions(+), 16 deletions(-)

Looks good to me. Peter, Thomas, any objections?

Thanks,

	Ingo