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: 628daa8d5abfd ("powerpc/powernv: Add RTC and NVRAM support plus RTAS fallbacks") Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> Signed-off-by: Nicholas Piggin <npig...@gmail.com> --- arch/powerpc/platforms/powernv/opal-nvram.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/platforms/powernv/opal-nvram.c b/arch/powerpc/platforms/powernv/opal-nvram.c index ba2ff06a2c98..1bceb95f422d 100644 --- a/arch/powerpc/platforms/powernv/opal-nvram.c +++ b/arch/powerpc/platforms/powernv/opal-nvram.c @@ -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) -- 2.17.0