diff options
Diffstat (limited to 'arch/powerpc/platforms/powernv/vas-fault.c')
| -rw-r--r-- | arch/powerpc/platforms/powernv/vas-fault.c | 155 |
1 files changed, 9 insertions, 146 deletions
diff --git a/arch/powerpc/platforms/powernv/vas-fault.c b/arch/powerpc/platforms/powernv/vas-fault.c index ac3a71ec3bd5..2729ac541fb3 100644 --- a/arch/powerpc/platforms/powernv/vas-fault.c +++ b/arch/powerpc/platforms/powernv/vas-fault.c @@ -26,150 +26,6 @@ */ #define VAS_FAULT_WIN_FIFO_SIZE (4 << 20) -static void dump_crb(struct coprocessor_request_block *crb) -{ - struct data_descriptor_entry *dde; - struct nx_fault_stamp *nx; - - dde = &crb->source; - pr_devel("SrcDDE: addr 0x%llx, len %d, count %d, idx %d, flags %d\n", - be64_to_cpu(dde->address), be32_to_cpu(dde->length), - dde->count, dde->index, dde->flags); - - dde = &crb->target; - pr_devel("TgtDDE: addr 0x%llx, len %d, count %d, idx %d, flags %d\n", - be64_to_cpu(dde->address), be32_to_cpu(dde->length), - dde->count, dde->index, dde->flags); - - nx = &crb->stamp.nx; - pr_devel("NX Stamp: PSWID 0x%x, FSA 0x%llx, flags 0x%x, FS 0x%x\n", - be32_to_cpu(nx->pswid), - be64_to_cpu(crb->stamp.nx.fault_storage_addr), - nx->flags, nx->fault_status); -} - -/* - * Update the CSB to indicate a translation error. - * - * User space will be polling on CSB after the request is issued. - * If NX can handle the request without any issues, it updates CSB. - * Whereas if NX encounters page fault, the kernel will handle the - * fault and update CSB with translation error. - * - * If we are unable to update the CSB means copy_to_user failed due to - * invalid csb_addr, send a signal to the process. - */ -static void update_csb(struct vas_window *window, - struct coprocessor_request_block *crb) -{ - struct coprocessor_status_block csb; - struct kernel_siginfo info; - struct task_struct *tsk; - void __user *csb_addr; - struct pid *pid; - int rc; - - /* - * NX user space windows can not be opened for task->mm=NULL - * and faults will not be generated for kernel requests. - */ - if (WARN_ON_ONCE(!window->task_ref.mm || !window->user_win)) - return; - - csb_addr = (void __user *)be64_to_cpu(crb->csb_addr); - - memset(&csb, 0, sizeof(csb)); - csb.cc = CSB_CC_FAULT_ADDRESS; - csb.ce = CSB_CE_TERMINATION; - csb.cs = 0; - csb.count = 0; - - /* - * NX operates and returns in BE format as defined CRB struct. - * So saves fault_storage_addr in BE as NX pastes in FIFO and - * expects user space to convert to CPU format. - */ - csb.address = crb->stamp.nx.fault_storage_addr; - csb.flags = 0; - - pid = window->task_ref.pid; - tsk = get_pid_task(pid, PIDTYPE_PID); - /* - * Process closes send window after all pending NX requests are - * completed. In multi-thread applications, a child thread can - * open a window and can exit without closing it. May be some - * requests are pending or this window can be used by other - * threads later. We should handle faults if NX encounters - * pages faults on these requests. Update CSB with translation - * error and fault address. If csb_addr passed by user space is - * invalid, send SEGV signal to pid saved in window. If the - * child thread is not running, send the signal to tgid. - * Parent thread (tgid) will close this window upon its exit. - * - * pid and mm references are taken when window is opened by - * process (pid). So tgid is used only when child thread opens - * a window and exits without closing it. - */ - if (!tsk) { - pid = window->task_ref.tgid; - tsk = get_pid_task(pid, PIDTYPE_PID); - /* - * Parent thread (tgid) will be closing window when it - * exits. So should not get here. - */ - if (WARN_ON_ONCE(!tsk)) - return; - } - - /* Return if the task is exiting. */ - if (tsk->flags & PF_EXITING) { - put_task_struct(tsk); - return; - } - - kthread_use_mm(window->task_ref.mm); - rc = copy_to_user(csb_addr, &csb, sizeof(csb)); - /* - * User space polls on csb.flags (first byte). So add barrier - * then copy first byte with csb flags update. - */ - if (!rc) { - csb.flags = CSB_V; - /* Make sure update to csb.flags is visible now */ - smp_mb(); - rc = copy_to_user(csb_addr, &csb, sizeof(u8)); - } - kthread_unuse_mm(window->task_ref.mm); - put_task_struct(tsk); - - /* Success */ - if (!rc) - return; - - pr_debug("Invalid CSB address 0x%p signalling pid(%d)\n", - csb_addr, pid_vnr(pid)); - - clear_siginfo(&info); - info.si_signo = SIGSEGV; - info.si_errno = EFAULT; - info.si_code = SEGV_MAPERR; - info.si_addr = csb_addr; - - /* - * process will be polling on csb.flags after request is sent to - * NX. So generally CSB update should not fail except when an - * application passes invalid csb_addr. So an error message will - * be displayed and leave it to user space whether to ignore or - * handle this signal. - */ - rcu_read_lock(); - rc = kill_pid_info(SIGSEGV, &info, pid); - rcu_read_unlock(); - - pr_devel("%s(): pid %d kill_proc_info() rc %d\n", __func__, - pid_vnr(pid), rc); -} - static void dump_fifo(struct vas_instance *vinst, void *entry) { unsigned long *end = vinst->fault_fifo + vinst->fault_fifo_size; @@ -272,7 +128,7 @@ irqreturn_t vas_fault_thread_fn(int irq, void *data) vinst->vas_id, vinst->fault_fifo, fifo, vinst->fault_crbs); - dump_crb(crb); + vas_dump_crb(crb); window = vas_pswid_to_window(vinst, be32_to_cpu(crb->stamp.nx.pswid)); @@ -293,7 +149,14 @@ irqreturn_t vas_fault_thread_fn(int irq, void *data) WARN_ON_ONCE(1); } else { - update_csb(window, crb); + /* + * NX sees faults only with user space windows. + */ + if (window->user_win) + vas_update_csb(crb, &window->task_ref); + else + WARN_ON_ONCE(!window->user_win); + /* * Return credit for send window after processing * fault CRB. |