CVS commit: src/sys/arch/powerpc/ibm4xx

["Rin Okuyama" <rin%netbsd.org@localhost>]

Module Name:    src
Committed By:   rin
Date:           Thu Apr 15 00:00:46 UTC 2021

Modified Files:
        src/sys/arch/powerpc/ibm4xx: pmap.c

Log Message:
Use uvm_km_alloc(9) with UVM_KMF_NOWAIT flag in pte_enter(), in order not to
sleep in pmap_enter(9) and pmap_kenter_pa(9), which can result in dead lock.

In most cases, pmap_enter(9) is used with PMAP_CANFAIL flag. In this case,
if pte_enter() fails due to uvm_km_alloc(9), we can safely return ENOMEM.
UVM layer will take care of it.

uvm_km_alloc(9) fails for pmap_enter(9) without PMAP_CANFAIL or for
pmap_kenter_pa(9), we have no choice but to panic there.

However, my testbeds for 403 and 405 survive more than a week at least
without hitting this panic.


To generate a diff of this commit:
cvs rdiff -u -r1.97 -r1.98 src/sys/arch/powerpc/ibm4xx/pmap.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.