From ac71380071d19d4ac7cd5f9fe4168d7109902cd5 Mon Sep 17 00:00:00 2001 From: Nathan Fontenot Date: Wed, 16 Dec 2015 14:54:05 -0600 Subject: [PATCH] powerpc/pseries: Add CPU dlpar remove functionality Add the ability to dlpar remove CPUs via hotplug rtas events, either by specifying the drc-index of the CPU to remove or providing a count of cpus to remove. To remove multiple cpus in a single request we create a list of possible DR (Dynamic Reconfiguration) cpus and their drc indexes that can be removed. We can then traverse the list remove each cpu and easily clean up in any cases of failure. Signed-off-by: Nathan Fontenot Signed-off-by: Michael Ellerman --- arch/powerpc/platforms/pseries/hotplug-cpu.c | 147 +++++++++++++++++++ arch/powerpc/platforms/pseries/pseries.h | 9 ++ 2 files changed, 156 insertions(+) diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c index a54aee982589..86c7ae3db50e 100644 --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c @@ -26,6 +26,7 @@ #include /* for idle_task_exit */ #include #include +#include #include #include #include @@ -565,6 +566,152 @@ static ssize_t dlpar_cpu_remove(struct device_node *dn, u32 drc_index) return 0; } +static struct device_node *cpu_drc_index_to_dn(u32 drc_index) +{ + struct device_node *dn; + u32 my_index; + int rc; + + for_each_node_by_type(dn, "cpu") { + rc = of_property_read_u32(dn, "ibm,my-drc-index", &my_index); + if (rc) + continue; + + if (my_index == drc_index) + break; + } + + return dn; +} + +static int dlpar_cpu_remove_by_index(u32 drc_index) +{ + struct device_node *dn; + int rc; + + dn = cpu_drc_index_to_dn(drc_index); + if (!dn) { + pr_warn("Cannot find CPU (drc index %x) to remove\n", + drc_index); + return -ENODEV; + } + + rc = dlpar_cpu_remove(dn, drc_index); + of_node_put(dn); + return rc; +} + +static int find_dlpar_cpus_to_remove(u32 *cpu_drcs, int cpus_to_remove) +{ + struct device_node *dn; + int cpus_found = 0; + int rc; + + /* We want to find cpus_to_remove + 1 CPUs to ensure we do not + * remove the last CPU. + */ + for_each_node_by_type(dn, "cpu") { + cpus_found++; + + if (cpus_found > cpus_to_remove) { + of_node_put(dn); + break; + } + + /* Note that cpus_found is always 1 ahead of the index + * into the cpu_drcs array, so we use cpus_found - 1 + */ + rc = of_property_read_u32(dn, "ibm,my-drc-index", + &cpu_drcs[cpus_found - 1]); + if (rc) { + pr_warn("Error occurred getting drc-index for %s\n", + dn->name); + of_node_put(dn); + return -1; + } + } + + if (cpus_found < cpus_to_remove) { + pr_warn("Failed to find enough CPUs (%d of %d) to remove\n", + cpus_found, cpus_to_remove); + } else if (cpus_found == cpus_to_remove) { + pr_warn("Cannot remove all CPUs\n"); + } + + return cpus_found; +} + +static int dlpar_cpu_remove_by_count(u32 cpus_to_remove) +{ + u32 *cpu_drcs; + int cpus_found; + int cpus_removed = 0; + int i, rc; + + pr_debug("Attempting to hot-remove %d CPUs\n", cpus_to_remove); + + cpu_drcs = kcalloc(cpus_to_remove, sizeof(*cpu_drcs), GFP_KERNEL); + if (!cpu_drcs) + return -EINVAL; + + cpus_found = find_dlpar_cpus_to_remove(cpu_drcs, cpus_to_remove); + if (cpus_found <= cpus_to_remove) { + kfree(cpu_drcs); + return -EINVAL; + } + + for (i = 0; i < cpus_to_remove; i++) { + rc = dlpar_cpu_remove_by_index(cpu_drcs[i]); + if (rc) + break; + + cpus_removed++; + } + + if (cpus_removed != cpus_to_remove) { + pr_warn("CPU hot-remove failed, adding back removed CPUs\n"); + + for (i = 0; i < cpus_removed; i++) + dlpar_cpu_add(cpu_drcs[i]); + + rc = -EINVAL; + } else { + rc = 0; + } + + kfree(cpu_drcs); + return rc; +} + +int dlpar_cpu(struct pseries_hp_errorlog *hp_elog) +{ + u32 count, drc_index; + int rc; + + count = hp_elog->_drc_u.drc_count; + drc_index = hp_elog->_drc_u.drc_index; + + lock_device_hotplug(); + + switch (hp_elog->action) { + case PSERIES_HP_ELOG_ACTION_REMOVE: + if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_COUNT) + rc = dlpar_cpu_remove_by_count(count); + else if (hp_elog->id_type == PSERIES_HP_ELOG_ID_DRC_INDEX) + rc = dlpar_cpu_remove_by_index(drc_index); + else + rc = -EINVAL; + break; + default: + pr_err("Invalid action (%d) specified\n", hp_elog->action); + rc = -EINVAL; + break; + } + + unlock_device_hotplug(); + return rc; +} + #ifdef CONFIG_ARCH_CPU_PROBE_RELEASE static ssize_t dlpar_cpu_probe(const char *buf, size_t count) diff --git a/arch/powerpc/platforms/pseries/pseries.h b/arch/powerpc/platforms/pseries/pseries.h index 8411c27293e4..7aa83f00ac62 100644 --- a/arch/powerpc/platforms/pseries/pseries.h +++ b/arch/powerpc/platforms/pseries/pseries.h @@ -73,6 +73,15 @@ static inline int dlpar_memory(struct pseries_hp_errorlog *hp_elog) } #endif +#ifdef CONFIG_HOTPLUG_CPU +int dlpar_cpu(struct pseries_hp_errorlog *hp_elog); +#else +static inline int dlpar_cpu(struct pseries_hp_errorlog *hp_elog) +{ + return -EOPNOTSUPP; +} +#endif + /* PCI root bridge prepare function override for pseries */ struct pci_host_bridge; int pseries_root_bridge_prepare(struct pci_host_bridge *bridge); -- 2.30.2