On Thu, Oct 25, 2018 at 10:53:12AM -0700, Florian Fainelli wrote: > Something like this below? It does not have to be an alternative > solution, I would find it useful for perf to make sure the vectors page > is present in the virtual address space by having an explicit test. perf > maintains, what do you think?
Yep, I'd swap the two tests merely because the check for 'sig' will be slightly cheaper than the mask-and-test of addr, but it probably doesn't make that much difference. > > diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c > index f4ea4c62c613..b045b48d368d 100644 > --- a/arch/arm/mm/fault.c > +++ b/arch/arm/mm/fault.c > @@ -173,6 +173,11 @@ __do_user_fault(struct task_struct *tsk, unsigned > long addr, > show_regs(regs); > } > #endif > +#ifndef CONFIG_KUSER_HELPERS > + if (((addr & PAGE_MASK) == 0xffff0000) && (sig == SIGSEGV)) > + printk(KERN_DEBUG "%s: CONFIG_KUSER_HELPERS disabled at > 0x%08lx\n", > + tsk->comm, addr); > +#endif > > tsk->thread.address = addr; > tsk->thread.error_code = fsr; > > > > > > BTW, I note that the help text for CONFIG_KUSER_HELPERS needs to be > > updated. > > > > > -- > Florian -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 12.1Mbps down 622kbps up According to speedtest.net: 11.9Mbps down 500kbps up
