Date: Sun, 4 May 2014 10:56:08 +0100 From: Andrew Turner <andrew@fubar.geek.nz> To: Bruce Evans <brde@optusnet.com.au> Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r265268 - projects/arm64/sys/arm64/arm64 Message-ID: <20140504105608.70a60909@bender.Home> In-Reply-To: <20140504182755.K1388@besplex.bde.org> References: <201405031527.s43FRUTg019278@svn.freebsd.org> <20140504182755.K1388@besplex.bde.org>
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On Sun, 4 May 2014 19:25:06 +1000 (EST)
Bruce Evans <brde@optusnet.com.au> wrote:
> On Sat, 3 May 2014, Andrew Turner wrote:
>
> > Log:
> > Replace panic with printf in spinlock_{enter,exit} as panic makes
> > use of spinlocks.
>
> printf has been broken to use spinlocks too. It used to be careful to
> use atomic operations to avoid locking. Most console drivers are
> broken too. Some serial ones avoid locking in debugger mode only.
This is a stub function. I need to implement it, however I'm working on
other parts of the early code and would prefer it if panic at least
told me what called it even if it is broken.
I'm not yet using a console driver and instead using EARLY_PRINTF with
a function that relies on the early boot code mapping the UART with an
identity map. This contains no locking and will produce incorrect
output when too many characters are sent to it, however as this code is
only run on a hardware simulator that appears to output data with no
latency this has not been a problem.
Andrew
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