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powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops 

commit 3b8070335f upstream.

The OPAL NVRAM driver does not sleep in case it gets OPAL_BUSY or
OPAL_BUSY_EVENT from firmware, which causes large scheduling
latencies, and various lockup errors to trigger (again, BMC reboot
can cause it).

Fix this by converting it to the standard form OPAL_BUSY loop that
sleeps.

Fixes: 628daa8d5a ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks")
Depends-on: 34dd25de9f ("powerpc/powernv: define a standard delay for OPAL_BUSY type retry 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
Nicholas Piggin 2018-04-10 21:49:33 +10:00 committed by Greg Kroah-Hartman
parent 7c854f2e1f
commit 25b6ee378d
1 changed files with 6 additions and 1 deletions
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7
arch/powerpc/platforms/powernv/opal-nvram.c
View File

@ -11,6 +11,7 @@
#define DEBUG
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of.h>
@ -56,8 +57,12 @@ 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)
if (rc == OPAL_BUSY_EVENT) {
msleep(OPAL_BUSY_DELAY_MS);
opal_poll_events(NULL);
} else if (rc == OPAL_BUSY) {
msleep(OPAL_BUSY_DELAY_MS);
}
}
if (rc)