linux-kernel - [PATCH 4.16 022/196] ARM: EXYNOS: Fix coupled CPU idle freeze on Exynos4210

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Message-Id: <20180422135105.268175706@linuxfoundation.org>
Date:   Sun, 22 Apr 2018 15:50:42 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Marc Zyngier <marc.zyngier@....com>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>
Subject: [PATCH 4.16 022/196] ARM: EXYNOS: Fix coupled CPU idle freeze on Exynos4210

4.16-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Marek Szyprowski <m.szyprowski@...sung.com>

commit a7480dbcf983c31d8111f864c848e8a75116a87d upstream.

Since commit 04c8b0f82c7d ("irqchip/gic: Make locking a BL_SWITCHER only
feature") coupled CPU idle freezes from time to time on Exynos4210. Later
commit 313c8c16ee62 ("PM / CPU: replace raw_notifier with atomic_notifier")
changed the context in which the CPU idle code is executed, what results
in fully reproducible freeze all the time. However, almost the same coupled
CPU idle code works fine on Exynos3250 regardless of the changes made in
the mentioned commits.

It turned out that the IPI call used on Exynos4210 is conflicting with the
change done in the first mentioned commit in GIC. Fix this by using the
same code path as for Exynos3250, instead of the IPI call for
synchronization with second CPU core, call dsb_sev() directly.

Tested on Exynos4210-based Trats and Origen boards.

Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
CC: <stable@...r.kernel.org> # v4.13+
Acked-by: Marc Zyngier <marc.zyngier@....com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/arm/mach-exynos/pm.c |    6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

--- a/arch/arm/mach-exynos/pm.c
+++ b/arch/arm/mach-exynos/pm.c
@@ -271,11 +271,7 @@ abort:
 				goto fail;

 			call_firmware_op(cpu_boot, 1);
-
-			if (soc_is_exynos3250())
-				dsb_sev();
-			else
-				arch_send_wakeup_ipi_mask(cpumask_of(1));
+			dsb_sev();
 		}
 	}
 fail: