Re: [PATCH v3 5/5] x86/entry: Make IA32 syscalls' availability depend on ia32_enabled()

[Nikolay Borisov]

On 19.06.23 г. 0:17 ч., Thomas Gleixner wrote:
> On Fri, Jun 16 2023 at 15:57, Nikolay Borisov wrote:
> > Another major aspect of supporting running of 32bit processes is the
> > ability to access 32bit syscalls. Such syscalls are invoked either by
> > using the legacy int 0x80 call gate interface or via the newer sysenter
> > instruction.
> >
> > Ensure that if ia32 emulation is disabled (either at compile time or
> > runtime) then those 2 syscall mechanisms are also disabled.
>
> AFAICT there are _three_ mechanisms for 32bit syscalls, no?

int 0x80 and sysenter make it 2? Which one is the 3rd one - the "native 
64bit syscall" used in for X32 ABI ? This patch specifically deals with 
the first 2?
> >   void __init idt_setup_traps(void)
> >   {
> >   	idt_setup_from_table(idt_table, def_idts, ARRAY_SIZE(def_idts), true);
> > +
> > +	if (ia32_enabled()) {
> > +		idt_setup_from_table(idt_table, ia32_idt, ARRAY_SIZE(ia32_idt),
> > +				     true);
>
> Just let it stick out. The 80 character limit is history.
>
> Thanks,
>
>          tglx