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Thu, 30 May 2024 09:59:49 +0100 Date: Thu, 30 May 2024 09:59:49 +0100 Message-ID: <86zfs7lloa.wl-maz@kernel.org> From: Marc Zyngier To: Samuel Holland Cc: Thomas Gleixner , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] irqchip/gic: Use smp_wmb() instead of dmb(ishst) In-Reply-To: <20240530005254.1495461-1-samuel.holland@sifive.com> References: <20240530005254.1495461-1-samuel.holland@sifive.com> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.2 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: samuel.holland@sifive.com, tglx@linutronix.de, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240530_015954_203666_1885F7F4 X-CRM114-Status: GOOD ( 23.31 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 30 May 2024 01:52:30 +0100, Samuel Holland wrote: > > This is equivalent on ARM, but also works on other architectures. > > Signed-off-by: Samuel Holland > --- > > drivers/irqchip/irq-gic.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c > index 98aa383e39db..dc2e4018a40c 100644 > --- a/drivers/irqchip/irq-gic.c > +++ b/drivers/irqchip/irq-gic.c > @@ -839,7 +839,7 @@ static void gic_ipi_send_mask(struct irq_data *d, const struct cpumask *mask) > * Ensure that stores to Normal memory are visible to the > * other CPUs before they observe us issuing the IPI. > */ > - dmb(ishst); > + smp_wmb(); > > /* this always happens on GIC0 */ > writel_relaxed(map << 16 | d->hwirq, gic_data_dist_base(&gic_data[0]) + GIC_DIST_SOFTINT); Equivalent, sure. But what does it gain us, given that the driver is only compiled on ARM systems? Additionally, you may also want to address the one in the hip04 driver, which has the same dmb instruction. Thanks, M. -- Without deviation from the norm, progress is not possible. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel