public inbox for linux-arm-kernel@lists.infradead.org
 help / color / mirror / Atom feed
From: arnd@arndb.de (Arnd Bergmann)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] iwlegacy: mark il_adjust_beacon_interval as noinline
Date: Wed, 09 Dec 2015 17:42:41 +0100	[thread overview]
Message-ID: <36263581.L8412YxJjp@wuerfel> (raw)

With the new optimized do_div() code, some versions of gcc
produce obviously incorrect code that leads to a link error
in iwlegacy/common.o:

drivers/built-in.o: In function `il_send_rxon_timing':
:(.text+0xa6b4d4): undefined reference to `____ilog2_NaN'
:(.text+0xa6b4f0): undefined reference to `__aeabi_uldivmod'

In a few thousand randconfig builds, I have seen this problem
a couple of times in this file, but never anywhere else in the
kernel, so we can try to work around this in the only file
that shows the behavior, by marking the il_adjust_beacon_interval
function as noinline, which convinces gcc to use the unoptimized
do_div() all the time.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c
index 887114582583..6308bb217454 100644
--- a/drivers/net/wireless/intel/iwlegacy/common.c
+++ b/drivers/net/wireless/intel/iwlegacy/common.c
@@ -3602,7 +3602,7 @@ il_is_ht40_tx_allowed(struct il_priv *il, struct ieee80211_sta_ht_cap *ht_cap)
 }
 EXPORT_SYMBOL(il_is_ht40_tx_allowed);
 
-static u16
+static u16 noinline
 il_adjust_beacon_interval(u16 beacon_val, u16 max_beacon_val)
 {
 	u16 new_val;

             reply	other threads:[~2015-12-09 16:42 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-12-09 16:42 Arnd Bergmann [this message]
2015-12-09 17:13 ` [PATCH] iwlegacy: mark il_adjust_beacon_interval as noinline Nicolas Pitre
2015-12-10 11:08 ` Stanislaw Gruszka
2015-12-11 11:50 ` Kalle Valo

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=36263581.L8412YxJjp@wuerfel \
    --to=arnd@arndb.de \
    --cc=linux-arm-kernel@lists.infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox