On 31/05/2017 10:32, Thomas Huth wrote:
> On 31.05.2017 10:21, Andrew Jones wrote:
>> On Tue, May 30, 2017 at 05:07:24PM +0200, Thomas Huth wrote:
>>> When running a powerpc kvm-unit-test, and there is accidentially
>>> no device tree available, the test ends up in an endless loop,
>>> spamming the console with "rtas_node: /rtas: FDT_ERR_BADMAGIC"
>>> messages: Somewhere the code calls abort() due to the missing
>>> device tree, and abort() calls exit() which in turn tries to
>>> shut down the VM with rtas_power_off(). rtas_power_off() needs
>>> the device tree again to look up the right RTAS token and we
>>> then end up in the next iteration.
>>> Fix it by adding some proper checks to rtas_power_off() and
>>> rtas_token().
>>>
>>> Signed-off-by: Thomas Huth <thuth@xxxxxxxxxx>
>>> ---
>>> lib/powerpc/rtas.c | 13 ++++++++++++-
>>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/lib/powerpc/rtas.c b/lib/powerpc/rtas.c
>>> index 3407e25..a1c560b 100644
>>> --- a/lib/powerpc/rtas.c
>>> +++ b/lib/powerpc/rtas.c
>>> @@ -74,6 +74,9 @@ int rtas_token(const char *service)
>>> const struct fdt_property *prop;
>>> u32 *token;
>>>
>>> + if (!dt_available())
>>> + return RTAS_UNKNOWN_SERVICE;
>>> +
>>> prop = fdt_get_property(dt_fdt(), rtas_node(), service, NULL);
>>> if (prop) {
>>> token = (u32 *)prop->data;
>>> @@ -116,6 +119,14 @@ int rtas_call(int token, int nargs, int nret, int *outputs, ...)
>>>
>>> void rtas_power_off(void)
>>> {
>>> - int ret = rtas_call(rtas_token("power-off"), 2, 1, NULL, -1, -1);
>>> + int token, ret;
>>> +
>>> + token = rtas_token("power-off");
>>> + if (token < 0) {
>>
>> token == RTAS_UNKNOWN_SERVICE ?
>
> Yes, that's likely better ... though the tokens are normally > 0, I just
> had a look at the spec and it does not say anything about whether they
> have to be positive or not, so negative tokens could happen, too.
> I'll send a v2...
in rtas_token(), token is u32, so a very big token number can appear as
a negative value. But how do you return an error code if the return can
be negative?
Do you plan to use something like
"error = rtas_token(&token, "power-off");"?
Thanks,
Laurent
