Re: [PATCH v5] arch/x86: port I/O tracing on x86

[Dan Raymond <raymod2@gmail.com>]

On 10/7/2023 11:56 AM, Dan Raymond wrote:
> Add support for port I/O tracing on x86.  Memory mapped I/O tracing is
> available on x86 via CONFIG_MMIOTRACE but that relies on page faults
> so it doesn't work with port I/O.  This feature uses tracepoints in a
> similar manner as CONFIG_TRACE_MMIO_ACCESS.
> 
> Signed-off-by: Dan Raymond <raymod2@gmail.com>
> Suggested-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> V1 -> V2:
>   - create header file for prototypes to silence new compiler warning
>   - reduce CPU overhead to 2 instructions (no branching) when tracing disabled
>   - fix imprecise IP logging by retrieving the IP off the stack instead of using
>     compile time labels
> 
> V2 -> V3:
>   - restore missing semicolon
> 
> V3 -> V4:
>   - make GPL licenses consistent
>   - change pointer arguments from (long) to (void *)
>   - eliminate include guard checks and use -DDISABLE_TRACEPOINTS instead to
>     disable tracepoints in arch/x86/boot/*
>   - fix compiler warnings due to signed/unsigned mismatch in arch_cmpxchg64()
> 
> V4 -> V5:
>   - add -DDISABLE_TRACEPOINTS to arch/x86/realmode/rm/Makefile

Can I get reviews on this please?