diff options
| -rw-r--r-- | arch/powerpc/include/asm/vas.h | 3 | ||||
| -rw-r--r-- | arch/powerpc/platforms/book3s/vas-api.c | 167 | ||||
| -rw-r--r-- | arch/powerpc/platforms/powernv/vas-fault.c | 155 |
3 files changed, 179 insertions, 146 deletions
diff --git a/arch/powerpc/include/asm/vas.h b/arch/powerpc/include/asm/vas.h index 71cff6d6bf3a..6b41c0818958 100644 --- a/arch/powerpc/include/asm/vas.h +++ b/arch/powerpc/include/asm/vas.h @@ -230,4 +230,7 @@ int vas_register_coproc_api(struct module *mod, enum vas_cop_type cop_type, void vas_unregister_coproc_api(void); int get_vas_user_win_ref(struct vas_user_win_ref *task_ref); +void vas_update_csb(struct coprocessor_request_block *crb, + struct vas_user_win_ref *task_ref); +void vas_dump_crb(struct coprocessor_request_block *crb); #endif /* __ASM_POWERPC_VAS_H */ diff --git a/arch/powerpc/platforms/book3s/vas-api.c b/arch/powerpc/platforms/book3s/vas-api.c index 4ce82500f4c5..30172e52e16b 100644 --- a/arch/powerpc/platforms/book3s/vas-api.c +++ b/arch/powerpc/platforms/book3s/vas-api.c @@ -10,6 +10,9 @@ #include <linux/fs.h> #include <linux/slab.h> #include <linux/uaccess.h> +#include <linux/kthread.h> +#include <linux/sched/signal.h> +#include <linux/mmu_context.h> #include <linux/io.h> #include <asm/vas.h> #include <uapi/asm/vas-api.h> @@ -94,6 +97,170 @@ int get_vas_user_win_ref(struct vas_user_win_ref *task_ref) return 0; } +/* + * Successful return must release the task reference with + * put_task_struct + */ +static bool ref_get_pid_and_task(struct vas_user_win_ref *task_ref, + struct task_struct **tskp, struct pid **pidp) +{ + struct task_struct *tsk; + struct pid *pid; + + pid = task_ref->pid; + tsk = get_pid_task(pid, PIDTYPE_PID); + if (!tsk) { + pid = 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 false; + } + + /* Return if the task is exiting. */ + if (tsk->flags & PF_EXITING) { + put_task_struct(tsk); + return false; + } + + *tskp = tsk; + *pidp = pid; + + return true; +} + +/* + * 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. + */ +void vas_update_csb(struct coprocessor_request_block *crb, + struct vas_user_win_ref *task_ref) +{ + 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(!task_ref->mm)) + 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; + + /* + * 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 (!ref_get_pid_and_task(task_ref, &tsk, &pid)) + return; + + kthread_use_mm(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(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); +} + +void vas_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); +} + static int coproc_open(struct inode *inode, struct file *fp) { struct coproc_instance *cp_inst; 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. |