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pseries: Fix semantics of RTAS int-on, int-off and set-xive functions 

Currently the ibm,int-on and ibm,int-off RTAS functions are implemented as
no-ops.  This is because when implemented as specified in PAPR they caused
Linux (which calls both int-on/off and set-xive) to end up with interrupts
masked when they should not be.  Since Linux's set-xive calls make the
int-on/off calls redundant, making them nops worked around the problem.

In fact, the problem was caused because there was a subtle bug in set-xive,
PAPR specifies that as well as updating the current priority, it also needs
to update the saved priority used by int-on/off.  With this bug fixed the
problem goes away.  This patch implements this more correct fix.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>
This commit is contained in:
David Gibson 2012-09-12 16:57:21 +00:00 committed by Alexander Graf
parent 53724ee565
commit 3fe719f467
1 changed files with 8 additions and 17 deletions
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25
hw/xics.c
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@ -270,13 +270,14 @@ static void write_xive_lsi(struct ics_state *ics, int srcno)
}
static void ics_write_xive(struct ics_state *ics, int nr, int server,
uint8_t priority)
uint8_t priority, uint8_t saved_priority)
{
int srcno = nr - ics->offset;
struct ics_irq_state *irq = ics->irqs + srcno;
irq->server = server;
irq->priority = priority;
irq->saved_priority = saved_priority;
if (irq->lsi) {
write_xive_lsi(ics, srcno);
@ -405,7 +406,7 @@ static void rtas_set_xive(sPAPREnvironment *spapr, uint32_t token,
return;
}
ics_write_xive(ics, nr, server, priority);
ics_write_xive(ics, nr, server, priority, priority);
rtas_st(rets, 0, 0); /* Success */
}
@ -453,14 +454,8 @@ static void rtas_int_off(sPAPREnvironment *spapr, uint32_t token,
return;
}
/* This is a NOP for now, since the described PAPR semantics don't
* seem to gel with what Linux does */
#if 0
struct ics_irq_state *irq = xics->irqs + (nr - xics->offset);
irq->saved_priority = irq->priority;
ics_write_xive_msi(xics, nr, irq->server, 0xff);
#endif
ics_write_xive(ics, nr, ics->irqs[nr - ics->offset].server, 0xff,
ics->irqs[nr - ics->offset].priority);
rtas_st(rets, 0, 0); /* Success */
}
@ -484,13 +479,9 @@ static void rtas_int_on(sPAPREnvironment *spapr, uint32_t token,
return;
}
/* This is a NOP for now, since the described PAPR semantics don't
* seem to gel with what Linux does */
#if 0
struct ics_irq_state *irq = xics->irqs + (nr - xics->offset);
ics_write_xive_msi(xics, nr, irq->server, irq->saved_priority);
#endif
ics_write_xive(ics, nr, ics->irqs[nr - ics->offset].server,
ics->irqs[nr - ics->offset].saved_priority,
ics->irqs[nr - ics->offset].saved_priority);
rtas_st(rets, 0, 0); /* Success */
}