linux-kernel - [PATCH 06/18] Blackfin Serial Driver: explain why we cannot cpu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Fri,  6 Mar 2009 14:42:48 +0800
From:	Bryan Wu <cooloney@...nel.org>
To:	alan@...rguk.ukuu.org.uk
Cc:	linux-kernel@...r.kernel.org,
	Mike Frysinger <vapier.adi@...il.com>,
	Bryan Wu <cooloney@...nel.org>
Subject: [PATCH 06/18] Blackfin Serial Driver: explain why we cannot cpu_relax() in early serial code

From: Mike Frysinger <vapier.adi@...il.com>

Signed-off-by: Mike Frysinger <vapier.adi@...il.com>
Signed-off-by: Bryan Wu <cooloney@...nel.org>
---
 drivers/serial/bfin_5xx.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c
index 5a163f6..de8709d 100644
--- a/drivers/serial/bfin_5xx.c
+++ b/drivers/serial/bfin_5xx.c
@@ -1190,6 +1190,10 @@ static __init void early_serial_putc(struct uart_port *port, int ch)
 	unsigned timeout = 0xffff;
 	struct bfin_serial_port *uart = (struct bfin_serial_port *)port;
 
+	/* We cannot cpu_relax() here as doing so on the BF561 relies
+	 * on the per-cpu region being setup, and since this is early
+	 * serial code, it may not yet be usable ...
+	 */
 	while ((!(UART_GET_LSR(uart) & THRE)) && --timeout)
 		barrier();
 
-- 
1.5.6.3
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/