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Re: kern/54994: Critical bug in uarea_poolpage_alloc() for archs with __HAVE_CPU_UAREA_ROUTINES

On 2020/02/24 9:29, Rin Okuyama wrote:
__HAVE_CPU_UAREA_ROUTINES is enabled for alpha, mips,
powerpc/{oae,ibm4xx,booke}, and riscv. I investigated whether it is
really necessary or not for these archs (except for riscv).

In short, most of these archs do *not* need direct-mapped physically
contiguous u-area for now, as far as I can see (source code reading
and experiment on powerpc/oea, just experiment on other archs). Only
the exception is powerpc/ibm4xx, which should also be fixed.

So is it time to retire __HAVE_CPU_UAREA_ROUTINES?

Oops, mips64 depends on direct-mapped u-area (with UPAGES == 1);
is turned off:

    117 #if (USPACE > PAGE_SIZE) || !defined(_LP64)
    135 #else
    136 	KASSERT(pmap_md_direct_mapped_vaddr_p(ua2));
    137 #endif

If this KASSERT is commented out, system hangs when exec /sbin/init,
and I cannot even enter ddb from console.


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