From: mark.rutland@arm.com (Mark Rutland)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 2/2] arm: psci: don't call CPU_OFF blindly
Date: Fri, 5 Sep 2014 12:22:19 +0100 [thread overview]
Message-ID: <1409916139-20127-3-git-send-email-mark.rutland@arm.com> (raw)
In-Reply-To: <1409916139-20127-1-git-send-email-mark.rutland@arm.com>
The generic PSCI operations for arm check the presence of a CPU_OFF ID
far too late, and in the absence of an ID will panic(), rather than
producing a warning.
This patch adds a psci_cpu_disable callback which tests the presence of
a CPU_OFF id. As this is called earlier than psci_cpu_die, the failure
can be handled gracefully without brining down the system. Additionally
a check is added for a UP trusted OS in the presence of PSCI 0.2+. Full
support will require the use of MIGRATE, but for now rejecting hotplug
will prevent psci_cpu_die from brining down the system.
The now redundant check for scpi_ops.cpu_off is removed from
psci_cpu_die. At the same time, the whitespace is corrected from seven
spaces to tabs.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Cc: Rob Herring <robh@kernel.org>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: Ian Campbell <ian.campbell@citrix.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
---
arch/arm/kernel/psci_smp.c | 36 +++++++++++++++++++++++++++++-------
1 file changed, 29 insertions(+), 7 deletions(-)
Stefano, I've followed your lead with the __ref annotation here, but I couldn't
figure out why they exist on cpu_die and cpu_kill; it feels rather dodgy. Do
you know why they were added, or if they are superfluous?
There are some other cleanups that should happen here (static,
CPU_METHOD_OF_DECLARE), but those will come as a later cleanups series.
diff --git a/arch/arm/kernel/psci_smp.c b/arch/arm/kernel/psci_smp.c
index 28a1db4..2b00d3c 100644
--- a/arch/arm/kernel/psci_smp.c
+++ b/arch/arm/kernel/psci_smp.c
@@ -56,17 +56,38 @@ static int psci_boot_secondary(unsigned int cpu, struct task_struct *idle)
}
#ifdef CONFIG_HOTPLUG_CPU
+int __ref 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;
+}
+
void __ref psci_cpu_die(unsigned int cpu)
{
- const struct psci_power_state ps = {
- .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
- };
+ const struct psci_power_state ps = {
+ .type = PSCI_POWER_STATE_TYPE_POWER_DOWN,
+ };
- if (psci_ops.cpu_off)
- psci_ops.cpu_off(ps);
+ psci_ops.cpu_off(ps);
- /* We should never return */
- panic("psci: cpu %d failed to shutdown\n", cpu);
+ /* We should never return */
+ panic("psci: cpu %d failed to shutdown\n", cpu);
}
int __ref psci_cpu_kill(unsigned int cpu)
@@ -109,6 +130,7 @@ bool __init psci_smp_available(void)
struct smp_operations __initdata psci_smp_ops = {
.smp_boot_secondary = psci_boot_secondary,
#ifdef CONFIG_HOTPLUG_CPU
+ .cpu_disable = psci_cpu_disable,
.cpu_die = psci_cpu_die,
.cpu_kill = psci_cpu_kill,
#endif
--
1.9.1
next prev parent reply other threads:[~2014-09-05 11:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-05 11:22 [PATCH 0/2] PSCI: don't call CPU_OFF when it might fail Mark Rutland
2014-09-05 11:22 ` [PATCH 1/2] arm64: psci: respect MIGRATE_INFO_TYPE Mark Rutland
2014-09-05 11:58 ` Sergei Shtylyov
2014-09-05 12:39 ` Mark Rutland
2014-09-05 11:22 ` Mark Rutland [this message]
2014-09-05 20:48 ` [PATCH 2/2] arm: psci: don't call CPU_OFF blindly Stefano Stabellini
2014-09-08 10:22 ` Mark Rutland
2014-09-05 20:53 ` [PATCH 0/2] PSCI: don't call CPU_OFF when it might fail Stefano Stabellini
2014-09-08 10:24 ` Mark Rutland
2014-09-08 21:44 ` Stefano Stabellini
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