Date: Sat, 18 Jan 2014 23:41:44 +0000 From: Julien Grall <julien.grall@linaro.org> To: Nathan Whitehorn <nwhitehorn@freebsd.org>, Warner Losh <imp@bsdimp.com> Cc: ian.campbell@citrix.com, stefano.stabellini@eu.citrix.com, xen-devel@lists.xen.org, freebsd-xen@freebsd.org, freebsd-arm@FreeBSD.org, gibbs@freebsd.org Subject: Re: [RFC] Add support for Xen ARM guest on FreeBSD Message-ID: <52DB1138.6010804@linaro.org> In-Reply-To: <52D89DC9.7050303@freebsd.org> References: <1389733267-20822-1-git-send-email-julien.grall@linaro.org> <24851B79-7EC7-4E3A-94DB-4B9B86FDFFFC@bsdimp.com> <52D6B62A.9000208@linaro.org> <52D73C4E.2080306@freebsd.org> <52D87B15.5090208@linaro.org> <52D89DC9.7050303@freebsd.org>
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Hello Nathan,
On 01/17/2014 03:04 AM, Nathan Whitehorn wrote:
> On 01/16/14 18:36, Julien Grall wrote:
>>
>>
>> On 01/16/2014 01:56 AM, Nathan Whitehorn wrote:
>> As I understand, only the simple bus code (see simplebus_attach) is
>> translating the interrupts in the device on a resource.
>> So if you have a node directly attached to the root node with
>> interrupts and MMIO, the driver won't be able to retrieve and
>> translate the interrupts via bus_alloc_resources.
> Why not? nexus on ARM, MIPS, PowerPC, and sparc64 can do this.
I have digged into the code to find the reason of my issue. FreeBSD is
receiving a VM fault when the driver (xen-dt) is trying to setup the IRQ.
This is because the GIC is not yet initialized but FreeBSD asks to
unmask the IRQ (sys/arm/arm/gic.c:306).
With this problem, all device nodes that are before the GIC in the
device tree can't have interrupts. For instance this simple device will
segfault on FreeBSD:
/ {
mybus {
compatible = "simple-bus";
mynode {
interrupt-parent = &gic;
interrupts = <...>;
};
gic: gic@xxxx {
interrupt-controller;
}
};
};
The node "mynode" will have to move after the GIC to be able to work
correctly.
--
Julien Grall
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