Messages in this thread Patch in this message | | | From | Qais Yousef <> | Subject | [PATCH] MIPS: Fix broken malta qemu | Date | Thu, 17 Mar 2016 21:08:09 +0000 |
| |
Malta defconfig compiles with GIC on. Hence when compiling for SMP it causes the new IPI code to be activated. But on qemu malta there's no GIC causing a BUG_ON(!ipidomain) to be hit in mips_smp_ipi_init().
Since in that configuration one can only run a single core SMP (!), skip IPI initialisation if we detect that this is the case. It is a sensible behaviour to introduce and should keep such possible configuration to run rather than die hard unnecessarily.
Signed-off-by: Qais Yousef <qsyousef@gmail.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org Cc: linux-kernel@vger.kernel.org --- arch/mips/kernel/smp.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/arch/mips/kernel/smp.c b/arch/mips/kernel/smp.c index 37708d9..27cb638 100644 --- a/arch/mips/kernel/smp.c +++ b/arch/mips/kernel/smp.c @@ -243,6 +243,18 @@ static int __init mips_smp_ipi_init(void) struct irq_domain *ipidomain; struct device_node *node; + /* + * In some cases like qemu-malta, it is desired to try SMP with + * a single core. Qemu-malta has no GIC, so an attempt to set any IPIs + * would cause a BUG_ON() to be triggered since there's no ipidomain. + * + * Since for a single core system IPIs aren't required really, skip the + * initialisation which should generally keep any such configurations + * happy and only fail hard when trying to truely run SMP. + */ + if (cpumask_weight(cpu_possible_mask) == 1) + return 0; + node = of_irq_find_parent(of_root); ipidomain = irq_find_matching_host(node, DOMAIN_BUS_IPI); -- 2.7.3
| |