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powerpc/powernv: Fix NVRAM sleep in invalid context when crashing 

Similarly to opal_event_shutdown, opal_nvram_write can be called in
the crash path with irqs disabled. Special case the delay to avoid
sleeping in invalid context.

Fixes: 3b8070335f ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops")
Cc: stable@vger.kernel.org # v3.2
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
This commit is contained in:
Nicholas Piggin 2018-05-15 01:59:47 +10:00 committed by Michael Ellerman
parent 497a0790e2
commit c1d2a31397
1 changed files with 12 additions and 2 deletions
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14
arch/powerpc/platforms/powernv/opal-nvram.c
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@ -44,6 +44,10 @@ static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
return count;
}
/*
* This can be called in the panic path with interrupts off, so use
* mdelay in that case.
*/
static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
{
s64 rc = OPAL_BUSY;
@ -58,10 +62,16 @@ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
rc = opal_write_nvram(__pa(buf), count, off);
if (rc == OPAL_BUSY_EVENT) {
msleep(OPAL_BUSY_DELAY_MS);
if (in_interrupt() || irqs_disabled())
mdelay(OPAL_BUSY_DELAY_MS);
else
msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
} else if (rc == OPAL_BUSY) {
msleep(OPAL_BUSY_DELAY_MS);
if (in_interrupt() || irqs_disabled())
mdelay(OPAL_BUSY_DELAY_MS);
else
msleep(OPAL_BUSY_DELAY_MS);
}
}