From 6aecee6ad41cf97c0270f72da032c10eef025bf0 Mon Sep 17 00:00:00 2001
From: Stuart Hayes <stuart.w.hayes@gmail.com>
Date: Wed, 26 Sep 2018 16:50:17 -0500
Subject: [PATCH] firmware: dell_rbu: Make payload memory uncachable
Git-commit: 6aecee6ad41cf97c0270f72da032c10eef025bf0
Patch-mainline: v4.20-rc1
References: bsc#1087978
The dell_rbu driver takes firmware update payloads and puts them in memory so
the system BIOS can find them after a reboot. This sometimes fails (though
rarely), because the memory containing the payload is in the CPU cache but
never gets written back to main memory before the system is rebooted (CPU
cache contents are lost on reboot).
With this patch, the payload memory will be changed to uncachable to ensure
that the payload is actually in main memory before the system is rebooted.
Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/firmware/dell_rbu.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/firmware/dell_rbu.c b/drivers/firmware/dell_rbu.c
index fb8af5cb7c9b..ccefa84f7305 100644
--- a/drivers/firmware/dell_rbu.c
+++ b/drivers/firmware/dell_rbu.c
@@ -45,6 +45,7 @@
#include <linux/moduleparam.h>
#include <linux/firmware.h>
#include <linux/dma-mapping.h>
+#include <asm/set_memory.h>
MODULE_AUTHOR("Abhay Salunke <abhay_salunke@dell.com>");
MODULE_DESCRIPTION("Driver for updating BIOS image on DELL systems");
@@ -181,6 +182,11 @@ static int create_packet(void *data, size_t length)
packet_data_temp_buf = NULL;
}
}
+ /*
+ * set to uncachable or it may never get written back before reboot
+ */
+ set_memory_uc((unsigned long)packet_data_temp_buf, 1 << ordernum);
+
spin_lock(&rbu_data.lock);
newpacket->data = packet_data_temp_buf;
@@ -349,6 +355,8 @@ static void packet_empty_list(void)
* to make sure there are no stale RBU packets left in memory
*/
memset(newpacket->data, 0, rbu_data.packetsize);
+ set_memory_wb((unsigned long)newpacket->data,
+ 1 << newpacket->ordernum);
free_pages((unsigned long) newpacket->data,
newpacket->ordernum);
kfree(newpacket);
--
2.19.2