From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Osipenko Subject: [PATCH v1 2/4] memory: tegra: Fix integer overflow on tick value calculation Date: Fri, 12 Apr 2019 01:12:48 +0300 Message-ID: <20190411221250.23233-3-digetx@gmail.com> References: <20190411221250.23233-1-digetx@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190411221250.23233-1-digetx@gmail.com> Sender: linux-kernel-owner@vger.kernel.org To: Thierry Reding , Jonathan Hunter Cc: linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-tegra@vger.kernel.org Multiplying the Memory Controller clock rate by the tick count results in an integer overflow and in result the truncated tick value is being programmed into hardware, such that the GR3D memory client performance is reduced by two times. Cc: stable Signed-off-by: Dmitry Osipenko --- drivers/memory/tegra/mc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c index 60474597180b..89e463952b8a 100644 --- a/drivers/memory/tegra/mc.c +++ b/drivers/memory/tegra/mc.c @@ -285,7 +285,7 @@ static int tegra_mc_setup_latency_allowance(struct tegra_mc *mc) u32 value; /* compute the number of MC clock cycles per tick */ - tick = mc->tick * clk_get_rate(mc->clk); + tick = (unsigned long long)mc->tick * clk_get_rate(mc->clk); do_div(tick, NSEC_PER_SEC); value = readl(mc->regs + MC_EMEM_ARB_CFG); -- 2.21.0