linux-kernel - [PATCH v2 06/28] clk: renesas: rzg2l: remove critical area

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]

Message-Id: <20230929053915.1530607-7-claudiu.beznea@bp.renesas.com>
Date:   Fri, 29 Sep 2023 08:38:53 +0300
From:   Claudiu <claudiu.beznea@...on.dev>
To:     geert+renesas@...der.be, mturquette@...libre.com, sboyd@...nel.org,
        robh+dt@...nel.org, krzysztof.kozlowski+dt@...aro.org,
        conor+dt@...nel.org, linus.walleij@...aro.org,
        gregkh@...uxfoundation.org, jirislaby@...nel.org,
        magnus.damm@...il.com, catalin.marinas@....com, will@...nel.org,
        quic_bjorande@...cinc.com, konrad.dybcio@...aro.org, arnd@...db.de,
        neil.armstrong@...aro.org, prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com
Cc:     linux-renesas-soc@...r.kernel.org, linux-clk@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-gpio@...r.kernel.org, linux-serial@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v2 06/28] clk: renesas: rzg2l: remove critical area

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

spinlock in rzg2l_mod_clock_endisable() is intended to protect the accesses
to hardware register. There is no need to protect the instructions that set
temporary variable which will be then written to register. With this only
one write to one clock register is executed thus locking/unlocking rmw_lock
is removed.

Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---

Changes in v2:
- removed also the spinlock
- s/reduce/remove in patch title

 drivers/clk/renesas/rzg2l-cpg.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index f411e428196c..d936832e098f 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -895,7 +895,6 @@ static int rzg2l_mod_clock_endisable(struct clk_hw *hw, bool enable)
 	struct rzg2l_cpg_priv *priv = clock->priv;
 	unsigned int reg = clock->off;
 	struct device *dev = priv->dev;
-	unsigned long flags;
 	u32 bitmask = BIT(clock->bit);
 	u32 value;
 	int error;
@@ -907,14 +906,12 @@ static int rzg2l_mod_clock_endisable(struct clk_hw *hw, bool enable)
 
 	dev_dbg(dev, "CLK_ON %u/%pC %s\n", CLK_ON_R(reg), hw->clk,
 		enable ? "ON" : "OFF");
-	spin_lock_irqsave(&priv->rmw_lock, flags);
 
 	value = bitmask << 16;
 	if (enable)
 		value |= bitmask;
-	writel(value, priv->base + CLK_ON_R(reg));
 
-	spin_unlock_irqrestore(&priv->rmw_lock, flags);
+	writel(value, priv->base + CLK_ON_R(reg));
 
 	if (!enable)
 		return 0;
-- 
2.39.2