[PATCH 2/6] ARM: move vmalloc() lazy-page table population

[Russell King (Oracle)]

On Mon, Mar 02, 2026 at 11:43:51AM +0100, Sebastian Andrzej Siewior wrote:
> On 2026-02-27 15:19:13 [+0000], Russell King (Oracle) wrote:
> > Split the vmalloc() lazy-page table population from
> > do_translation_fault() into a new vmalloc_fault() function.
> > 
> > Signed-off-by: Russell King (Oracle) <rmk+kernel at armlinux.org.uk>
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy at linutronix.de>
> 
> > --- a/arch/arm/mm/fault.c
> > +++ b/arch/arm/mm/fault.c
> > @@ -261,6 +261,70 @@ static inline bool ttbr0_usermode_access_allowed(struct pt_regs *regs)
> >  }
> >  #endif
> >  
> > +/*
> > + * Handle a vmalloc fault, copying the non-leaf page table entries from
> > + * init_mm.pgd. Any kernel context can trigger this, so we must not sleep
> > + * or enable interrupts. Having two CPUs execute this for the same page is
> 
> "unconditionally enable interrupts."? It wouldn't be wrong to enable
> them if the calling context had them enabled, right?

I don't know where you got "unconditionally enable interrupts" from the
comment - it says the exact opposite.

> 
> > + * no problem, we'll just copy the same data twice.
> > + *
> > + * Returns false on failure.
> > + */
> > +static bool __kprobes __maybe_unused vmalloc_fault(unsigned long addr)
> 
> Maybe handle_vmalloc_fault().

x86:

static noinline int vmalloc_fault(unsigned long address)
{
...

I prefer to keep the name the same.

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