From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Fri, 5 Sep 2014 12:22:18 +0100 Subject: [PATCH 1/2] arm64: psci: respect MIGRATE_INFO_TYPE In-Reply-To: <1409916139-20127-1-git-send-email-mark.rutland@arm.com> References: <1409916139-20127-1-git-send-email-mark.rutland@arm.com> Message-ID: <1409916139-20127-2-git-send-email-mark.rutland@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Commit e71246a23acb (PSCI: Add initial support for PSCIv0.2 functions) added hooks for MIGRATE_INFO_TYPE, but didn't call it anywhere. This means that currently a UP Trusted OS can reject CPU_OFF calls, which will cause things to blow up. This patch ensures we test MIGRATE_INFO_TYPE before calling CPU_OFF. If there's a UP trusted OS hotplug is rejected. Full support for PSCI in the presence of a UP trusted OS will require the use of MIGRATE and will have to come as a later patch. Signed-off-by: Mark Rutland Cc: Ashwin Chaugule Cc: Rob Herring Cc: Stefano Stabellini Cc: Ian Campbell Cc: Christoffer Dall Cc: Will Deacon Cc: Catalin Marinas --- arch/arm64/kernel/psci.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/arch/arm64/kernel/psci.c b/arch/arm64/kernel/psci.c index 5539547..a5407af 100644 --- a/arch/arm64/kernel/psci.c +++ b/arch/arm64/kernel/psci.c @@ -386,6 +386,20 @@ static int cpu_psci_cpu_disable(unsigned int cpu) /* Fail early if we don't have CPU_OFF support */ if (!psci_ops.cpu_off) return -EOPNOTSUPP; + + /* + * In the presence of a UP trusted OS, it might not be possible to + * hotplug certain CPUs, and CPU_OFF may return (which would be bad). + * Supporting a UP trusted OS requires careful use of + * MIGRATE_INFO_UP_CPU and MIGRATE, so for now fail in the presence of + * a UP Trusted OS. + */ + if (psci_ops.migrate_info_type && + psci_ops.migrate_info_type() != PSCI_0_2_TOS_MP) { + pr_warn("Unable to handle UP trusted OS\n"); + return -EPERM; + } + return 0; } -- 1.9.1