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Revert "powerpc/rtas: Implement reentrant rtas call"

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At the time this was submitted by Leonardo, I confirmed -- or thought
I had confirmed -- with PowerVM partition firmware development that
the following RTAS functions:

- ibm,get-xive
- ibm,int-off
- ibm,int-on
- ibm,set-xive

were safe to call on multiple CPUs simultaneously, not only with
respect to themselves as indicated by PAPR, but with arbitrary other
RTAS calls:

https://lore.kernel.org/linuxppc-dev/875zcy2v8o.fsf@linux.ibm.com/

Recent discussion with firmware development makes it clear that this
is not true, and that the code in commit b664db8e3f ("powerpc/rtas:
Implement reentrant rtas call") is unsafe, likely explaining several
strange bugs we've seen in internal testing involving DLPAR and
LPM. These scenarios use ibm,configure-connector, whose internal state
can be corrupted by the concurrent use of the "reentrant" functions,
leading to symptoms like endless busy statuses from RTAS.

Fixes: b664db8e3f ("powerpc/rtas: Implement reentrant rtas call")
Cc: stable@vger.kernel.org # v5.8+
Signed-off-by: Nathan Lynch <nathanl@linux.ibm.com>
Reviewed-by: Laurent Dufour <laurent.dufour@fr.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220907220111.223267-1-nathanl@linux.ibm.com
This commit is contained in:
Nathan Lynch
2022-09-07 17:01:11 -05:00
committed by Michael Ellerman
parent 71a92e99c4
commit f88aabad33
5 changed files with 11 additions and 99 deletions
Download Patch File Download Diff File Expand all files Collapse all files
arch/powerpc/sysdev/xics/ics-rtas.c
+11 -11
View File
@@ -36,8 +36,8 @@ static void ics_rtas_unmask_irq(struct irq_data *d)
server = xics_get_irq_server(d->irq, irq_data_get_affinity_mask(d), 0);
call_status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL, hw_irq,
server, DEFAULT_PRIORITY);
call_status = rtas_call(ibm_set_xive, 3, 1, NULL, hw_irq, server,
DEFAULT_PRIORITY);
if (call_status != 0) {
printk(KERN_ERR
"%s: ibm_set_xive irq %u server %x returned %d\n",
@@ -46,7 +46,7 @@ static void ics_rtas_unmask_irq(struct irq_data *d)
}
/* Now unmask the interrupt (often a no-op) */
call_status = rtas_call_reentrant(ibm_int_on, 1, 1, NULL, hw_irq);
call_status = rtas_call(ibm_int_on, 1, 1, NULL, hw_irq);
if (call_status != 0) {
printk(KERN_ERR "%s: ibm_int_on irq=%u returned %d\n",
__func__, hw_irq, call_status);
@@ -68,7 +68,7 @@ static void ics_rtas_mask_real_irq(unsigned int hw_irq)
if (hw_irq == XICS_IPI)
return;
call_status = rtas_call_reentrant(ibm_int_off, 1, 1, NULL, hw_irq);
call_status = rtas_call(ibm_int_off, 1, 1, NULL, hw_irq);
if (call_status != 0) {
printk(KERN_ERR "%s: ibm_int_off irq=%u returned %d\n",
__func__, hw_irq, call_status);
@@ -76,8 +76,8 @@ static void ics_rtas_mask_real_irq(unsigned int hw_irq)
}
/* Have to set XIVE to 0xff to be able to remove a slot */
call_status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL, hw_irq,
xics_default_server, 0xff);
call_status = rtas_call(ibm_set_xive, 3, 1, NULL, hw_irq,
xics_default_server, 0xff);
if (call_status != 0) {
printk(KERN_ERR "%s: ibm_set_xive(0xff) irq=%u returned %d\n",
__func__, hw_irq, call_status);
@@ -108,7 +108,7 @@ static int ics_rtas_set_affinity(struct irq_data *d,
if (hw_irq == XICS_IPI || hw_irq == XICS_IRQ_SPURIOUS)
return -1;
status = rtas_call_reentrant(ibm_get_xive, 1, 3, xics_status, hw_irq);
status = rtas_call(ibm_get_xive, 1, 3, xics_status, hw_irq);
if (status) {
printk(KERN_ERR "%s: ibm,get-xive irq=%u returns %d\n",
@@ -126,8 +126,8 @@ static int ics_rtas_set_affinity(struct irq_data *d,
pr_debug("%s: irq %d [hw 0x%x] server: 0x%x\n", __func__, d->irq,
hw_irq, irq_server);
status = rtas_call_reentrant(ibm_set_xive, 3, 1, NULL,
hw_irq, irq_server, xics_status[1]);
status = rtas_call(ibm_set_xive, 3, 1, NULL,
hw_irq, irq_server, xics_status[1]);
if (status) {
printk(KERN_ERR "%s: ibm,set-xive irq=%u returns %d\n",
@@ -158,7 +158,7 @@ static int ics_rtas_check(struct ics *ics, unsigned int hw_irq)
return -EINVAL;
/* Check if RTAS knows about this interrupt */
rc = rtas_call_reentrant(ibm_get_xive, 1, 3, status, hw_irq);
rc = rtas_call(ibm_get_xive, 1, 3, status, hw_irq);
if (rc)
return -ENXIO;
@@ -174,7 +174,7 @@ static long ics_rtas_get_server(struct ics *ics, unsigned long vec)
{
int rc, status[2];
rc = rtas_call_reentrant(ibm_get_xive, 1, 3, status, vec);
rc = rtas_call(ibm_get_xive, 1, 3, status, vec);
if (rc)
return -1;
return status[0];