Date: Mon, 27 Jun 2005 05:44:50 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Marcel Moolenaar <marcel@xcllnt.net> Cc: Stephan Uphoff <ups@freebsd.org>, cvs-src@freebsd.org, src-committers@freebsd.org, cvs-all@freebsd.org Subject: Re: cvs commit: src/sys/i386/i386 trap.c src/sys/amd64/amd64 trap.c Message-ID: <20050627050618.W34733@delplex.bde.org> In-Reply-To: <7c65ef6b909f86fa7f5a8aa041773a72@xcllnt.net> References: <200506252214.j5PMEgip000380@repoman.freebsd.org> <7c65ef6b909f86fa7f5a8aa041773a72@xcllnt.net>
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On Sat, 25 Jun 2005, Marcel Moolenaar wrote:
> On Jun 25, 2005, at 3:14 PM, Stephan Uphoff wrote:
>
>> ups 2005-06-25 22:14:42 UTC
>>
>> FreeBSD src repository
>>
>> Modified files:
>> sys/i386/i386 trap.c
>> sys/amd64/amd64 trap.c
>> Log:
>> Disable the interrupts in trap_fatal before calling kdb_trap.
>> (required now that critical sections no longer block interrupts)
>
> Why does this only apply to i386 and amd64?
Because it is a wrong fix. Many arches used to hard-disable interrupts
in their MD kdb_trap(), but this rotted to critical_enter() in rev.1.1
of subr_kdb.c. "Many arches":
alpha: used intr_disable(), but misplaced it so that it didn't protect
the state global
amd64: used disable_intr() correctly
arm: used only splhigh()
i386: used disable_intr() correctly
ia64: used intr_disable() correctly
sparc64: no locking except that given by cndbctl()
Loss of cndbctl() for all arches in rev.1.1 of subr_kdb.c is more
serious. critical_enter() blocks most things, but calling cndbctl()
is critical for the console drivers that depend on it to keep track
of when console i/o is done from within ddb. Mainly syscons depends
on it. Calls to cndbctl() used to only be missing for arm.
Bruce
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