Re: [PATCH] x86: add hintable NOPs emulation

[Marcos Del Sol Vives <marcos@orca.pet>]

El 21/08/2025 a las 20:40, David Laight escribió:
> On Thu, 21 Aug 2025 14:46:59 +0200
> Peter Zijlstra <peterz@infradead.org> wrote:
>> It would mean cloning the page as private. Yes you can do it, uprobes
>> has all the code for this. But it has non-trivial memory overhead.
> 
> I was thinking it would be safe to do this change without cloning the page.
> After all the change is needed for all processes executing the code.
> That might only be easy on UP systems - but I doubt the affected CPU are SMP.
> 
> 	David
> 

Actually...

marcos@vdx3:~$ nproc
2
marcos@vdx3:~$ cat /proc/cpuinfo
processor       : 0
vendor_id       : Vortex86 SoC
cpu family      : 6
model           : 1
model name      : Vortex86DX3
stepping        : 1
cpu MHz         : 1000.017
physical id     : 0
siblings        : 1
core id         : 0
cpu cores       : 1
apicid          : 0
initial apicid  : 0
fdiv_bug        : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 3
wp              : yes
flags           : fpu pse tsc msr cx8 apic sep pge cmov mmx fxsr sse cpuid
bugs            : itlb_multihit
bogomips        : 2000.03
clflush size    : 32
cache_alignment : 32
address sizes   : 32 bits physical, 32 bits virtual
power management:

processor       : 1
vendor_id       : Vortex86 SoC
cpu family      : 6
model           : 1
model name      : Vortex86DX3
stepping        : 1
cpu MHz         : 1000.017
physical id     : 1
siblings        : 1
core id         : 0
cpu cores       : 1
apicid          : 1
initial apicid  : 1
fdiv_bug        : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 3
wp              : yes
flags           : fpu pse tsc msr cx8 apic sep pge cmov mmx fxsr sse cpuid
bugs            : itlb_multihit
bogomips        : 2000.03
clflush size    : 32
cache_alignment : 32
address sizes   : 32 bits physical, 32 bits virtual
power management:

Vortex SoCs are true oddballs, aren't they?