From 91dc182ca6e25ee8b648ed2fb2a41859ead34903 Mon Sep 17 00:00:00 2001 From: Dave C Boutcher Date: Fri, 13 Jan 2006 18:39:24 -0600 Subject: [PATCH] powerpc: special-case ibm,suspend-me RTAS call Handle the ibm,suspend-me RTAS call specially. It needs to be wrapped in a set of synchronization hypervisor calls (H_Join). When the H_Join calls are made on all CPUs, the intent is that only one will return with H_Continue, meaning that he is the "last man standing". That CPU then issues the ibm,suspend-me call. What is interesting, of course, is that the CPU running when the rtas syscall is made, may NOT be the CPU that ultimately executes the ibm,suspend-me rtas call. Signed-off-by: Dave Boutcher Signed-off-by: Paul Mackerras --- arch/powerpc/kernel/rtas.c | 96 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 95 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/kernel/rtas.c') diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c index 4b9cfe4637b1..7fe4a5c944c9 100644 --- a/arch/powerpc/kernel/rtas.c +++ b/arch/powerpc/kernel/rtas.c @@ -36,6 +36,11 @@ struct rtas_t rtas = { .lock = SPIN_LOCK_UNLOCKED }; +struct rtas_suspend_me_data { + long waiting; + struct rtas_args *args; +}; + EXPORT_SYMBOL(rtas); DEFINE_SPINLOCK(rtas_data_buf_lock); @@ -556,6 +561,80 @@ void rtas_os_term(char *str) } while (status == RTAS_BUSY); } +static int ibm_suspend_me_token = RTAS_UNKNOWN_SERVICE; +#ifdef CONFIG_PPC_PSERIES +static void rtas_percpu_suspend_me(void *info) +{ + long rc; + long flags; + struct rtas_suspend_me_data *data = + (struct rtas_suspend_me_data *)info; + + /* + * We use "waiting" to indicate our state. As long + * as it is >0, we are still trying to all join up. + * If it goes to 0, we have successfully joined up and + * one thread got H_Continue. If any error happens, + * we set it to <0. + */ + local_irq_save(flags); + do { + rc = plpar_hcall_norets(H_JOIN); + smp_rmb(); + } while (rc == H_Success && data->waiting > 0); + if (rc == H_Success) + goto out; + + if (rc == H_Continue) { + data->waiting = 0; + rtas_call(ibm_suspend_me_token, 0, 1, + data->args->args); + } else { + data->waiting = -EBUSY; + printk(KERN_ERR "Error on H_Join hypervisor call\n"); + } + +out: + /* before we restore interrupts, make sure we don't + * generate a spurious soft lockup errors + */ + touch_softlockup_watchdog(); + local_irq_restore(flags); + return; +} + +static int rtas_ibm_suspend_me(struct rtas_args *args) +{ + int i; + + struct rtas_suspend_me_data data; + + data.waiting = 1; + data.args = args; + + /* Call function on all CPUs. One of us will make the + * rtas call + */ + if (on_each_cpu(rtas_percpu_suspend_me, &data, 1, 0)) + data.waiting = -EINVAL; + + if (data.waiting != 0) + printk(KERN_ERR "Error doing global join\n"); + + /* Prod each CPU. This won't hurt, and will wake + * anyone we successfully put to sleep with H_Join + */ + for_each_cpu(i) + plpar_hcall_norets(H_PROD, i); + + return data.waiting; +} +#else /* CONFIG_PPC_PSERIES */ +static int rtas_ibm_suspend_me(struct rtas_args *args) +{ + return -ENOSYS; +} +#endif asmlinkage int ppc_rtas(struct rtas_args __user *uargs) { @@ -563,6 +642,7 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs) unsigned long flags; char *buff_copy, *errbuf = NULL; int nargs; + int rc; if (!capable(CAP_SYS_ADMIN)) return -EPERM; @@ -581,6 +661,17 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs) nargs * sizeof(rtas_arg_t)) != 0) return -EFAULT; + if (args.token == RTAS_UNKNOWN_SERVICE) + return -EINVAL; + + /* Need to handle ibm,suspend_me call specially */ + if (args.token == ibm_suspend_me_token) { + rc = rtas_ibm_suspend_me(&args); + if (rc) + return rc; + goto copy_return; + } + buff_copy = get_errorlog_buffer(); spin_lock_irqsave(&rtas.lock, flags); @@ -604,6 +695,7 @@ asmlinkage int ppc_rtas(struct rtas_args __user *uargs) kfree(buff_copy); } + copy_return: /* Copy out args. */ if (copy_to_user(uargs->args + nargs, args.args + nargs, @@ -675,8 +767,10 @@ void __init rtas_initialize(void) * the stop-self token if any */ #ifdef CONFIG_PPC64 - if (_machine == PLATFORM_PSERIES_LPAR) + if (_machine == PLATFORM_PSERIES_LPAR) { rtas_region = min(lmb.rmo_size, RTAS_INSTANTIATE_MAX); + ibm_suspend_me_token = rtas_token("ibm,suspend-me"); + } #endif rtas_rmo_buf = lmb_alloc_base(RTAS_RMOBUF_MAX, PAGE_SIZE, rtas_region); -- cgit v1.2.1