Re: [PATCH 2/4] ARM: Fix register constraints in run_in_exception_handler()

[Orzel, Michal]

On 08/02/2025 01:02, Andrew Cooper wrote:
> 
> 
> Right now, run_in_exception_handler() takes an input in an arbitrary register,
> and clobbers BUG_FN_REG.  This causes the compiler to calculate fn in the
> wrong regsiter.
> 
> Instead, use `register asm()` which is the normal way of tying register
> constraints to exact registers.
> 
> Bloat-o-meter reports:
> 
>   ARM64:
>     Function                                     old     new   delta
>     dump_registers                               356     348      -8
> 
>   ARM32:
>     ns16550_poll                                  52      48      -4
>     dump_registers                               432     428      -4
> 
> The other instruction dropped in ARM64's dump_registers() is an alignment nop.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Reviewed-by: Michal Orzel <michal.or...@amd.com>

~Michal