linux-kernel - [PATCH AUTOSEL 5.7 17/58] ARM: exynos: MCPM: Restore big.LITTLE cpuidle support

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]

Date:   Sat,  8 Aug 2020 19:36:43 -0400
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Lukasz Luba <lukasz.luba@....com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Sasha Levin <sashal@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org
Subject: [PATCH AUTOSEL 5.7 17/58] ARM: exynos: MCPM: Restore big.LITTLE cpuidle support

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

[ Upstream commit ea9dd8f61c8a890843f68e8dc0062ce78365aab8 ]

Call exynos_cpu_power_up(cpunr) unconditionally. This is needed by the
big.LITTLE cpuidle driver and has no side-effects on other code paths.

The additional soft-reset call during little core power up has been added
to properly boot all cores on the Exynos5422-based boards with secure
firmware (like Odroid XU3/XU4 family). This however broke big.LITTLE
CPUidle driver, which worked only on boards without secure firmware (like
Peach-Pit/Pi Chromebooks). Apply the workaround only when board is
running under secure firmware.

Fixes: 833b5794e330 ("ARM: EXYNOS: reset Little cores when cpu is up")
Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Reviewed-by: Lukasz Luba <lukasz.luba@....com>
Signed-off-by: Krzysztof Kozlowski <krzk@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/arm/mach-exynos/mcpm-exynos.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm/mach-exynos/mcpm-exynos.c b/arch/arm/mach-exynos/mcpm-exynos.c
index 9a681b421ae11..cd861c57d5adf 100644
--- a/arch/arm/mach-exynos/mcpm-exynos.c
+++ b/arch/arm/mach-exynos/mcpm-exynos.c
@@ -26,6 +26,7 @@
 #define EXYNOS5420_USE_L2_COMMON_UP_STATE	BIT(30)
 
 static void __iomem *ns_sram_base_addr __ro_after_init;
+static bool secure_firmware __ro_after_init;
 
 /*
  * The common v7_exit_coherency_flush API could not be used because of the
@@ -58,15 +59,16 @@ static void __iomem *ns_sram_base_addr __ro_after_init;
 static int exynos_cpu_powerup(unsigned int cpu, unsigned int cluster)
 {
 	unsigned int cpunr = cpu + (cluster * EXYNOS5420_CPUS_PER_CLUSTER);
+	bool state;
 
 	pr_debug("%s: cpu %u cluster %u\n", __func__, cpu, cluster);
 	if (cpu >= EXYNOS5420_CPUS_PER_CLUSTER ||
 		cluster >= EXYNOS5420_NR_CLUSTERS)
 		return -EINVAL;
 
-	if (!exynos_cpu_power_state(cpunr)) {
-		exynos_cpu_power_up(cpunr);
-
+	state = exynos_cpu_power_state(cpunr);
+	exynos_cpu_power_up(cpunr);
+	if (!state && secure_firmware) {
 		/*
 		 * This assumes the cluster number of the big cores(Cortex A15)
 		 * is 0 and the Little cores(Cortex A7) is 1.
@@ -258,6 +260,8 @@ static int __init exynos_mcpm_init(void)
 		return -ENOMEM;
 	}
 
+	secure_firmware = exynos_secure_firmware_available();
+
 	/*
 	 * To increase the stability of KFC reset we need to program
 	 * the PMU SPARE3 register
-- 
2.25.1