From: Stuart Hayes <stuart.w.hayes@xxxxxxxxx> 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@xxxxxxxxx> --- This patch has been discussed previously, see history at https://patchwork.kernel.org/patch/10512079/ 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@xxxxxxxx>"); 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); -- 2.19.0.221.g150f307af
