diff options
Diffstat (limited to 'drivers/misc/cxl')
| -rw-r--r-- | drivers/misc/cxl/Makefile | 3 | ||||
| -rw-r--r-- | drivers/misc/cxl/api.c | 6 | ||||
| -rw-r--r-- | drivers/misc/cxl/context.c | 15 | ||||
| -rw-r--r-- | drivers/misc/cxl/cxl.h | 15 | ||||
| -rw-r--r-- | drivers/misc/cxl/fault.c | 129 | ||||
| -rw-r--r-- | drivers/misc/cxl/file.c | 25 | ||||
| -rw-r--r-- | drivers/misc/cxl/pci.c | 1 |
7 files changed, 144 insertions, 50 deletions
diff --git a/drivers/misc/cxl/Makefile b/drivers/misc/cxl/Makefile index 6982f603f..be2ac5ce3 100644 --- a/drivers/misc/cxl/Makefile +++ b/drivers/misc/cxl/Makefile @@ -1,4 +1,5 @@ -ccflags-y := -Werror -Wno-unused-const-variable +ccflags-y := $(call cc-disable-warning, unused-const-variable) +ccflags-$(CONFIG_PPC_WERROR) += -Werror cxl-y += main.o file.o irq.o fault.o native.o cxl-y += context.o sysfs.o debugfs.o pci.o trace.o diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c index 103baf0e0..ea3eeb701 100644 --- a/drivers/misc/cxl/api.c +++ b/drivers/misc/cxl/api.c @@ -25,7 +25,6 @@ struct cxl_context *cxl_dev_context_init(struct pci_dev *dev) afu = cxl_pci_to_afu(dev); - get_device(&afu->dev); ctx = cxl_context_alloc(); if (IS_ERR(ctx)) { rc = PTR_ERR(ctx); @@ -61,7 +60,6 @@ err_mapping: err_ctx: kfree(ctx); err_dev: - put_device(&afu->dev); return ERR_PTR(rc); } EXPORT_SYMBOL_GPL(cxl_dev_context_init); @@ -87,8 +85,6 @@ int cxl_release_context(struct cxl_context *ctx) if (ctx->status >= STARTED) return -EBUSY; - put_device(&ctx->afu->dev); - cxl_context_free(ctx); return 0; @@ -176,7 +172,7 @@ int cxl_start_context(struct cxl_context *ctx, u64 wed, if (task) { ctx->pid = get_task_pid(task, PIDTYPE_PID); - get_pid(ctx->pid); + ctx->glpid = get_task_pid(task->group_leader, PIDTYPE_PID); kernel = false; } diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c index 2faa1270d..262b88eac 100644 --- a/drivers/misc/cxl/context.c +++ b/drivers/misc/cxl/context.c @@ -42,7 +42,7 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master, spin_lock_init(&ctx->sste_lock); ctx->afu = afu; ctx->master = master; - ctx->pid = NULL; /* Set in start work ioctl */ + ctx->pid = ctx->glpid = NULL; /* Set in start work ioctl */ mutex_init(&ctx->mapping_lock); ctx->mapping = mapping; @@ -97,6 +97,12 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master, ctx->pe = i; ctx->elem = &ctx->afu->spa[i]; ctx->pe_inserted = false; + + /* + * take a ref on the afu so that it stays alive at-least till + * this context is reclaimed inside reclaim_ctx. + */ + cxl_afu_get(afu); return 0; } @@ -211,7 +217,11 @@ int __detach_context(struct cxl_context *ctx) WARN_ON(cxl_detach_process(ctx) && cxl_adapter_link_ok(ctx->afu->adapter)); flush_work(&ctx->fault_work); /* Only needed for dedicated process */ + + /* release the reference to the group leader and mm handling pid */ put_pid(ctx->pid); + put_pid(ctx->glpid); + cxl_ctx_put(); return 0; } @@ -278,6 +288,9 @@ static void reclaim_ctx(struct rcu_head *rcu) if (ctx->irq_bitmap) kfree(ctx->irq_bitmap); + /* Drop ref to the afu device taken during cxl_context_init */ + cxl_afu_put(ctx->afu); + kfree(ctx); } diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h index 0cfb9c129..a521bc72c 100644 --- a/drivers/misc/cxl/cxl.h +++ b/drivers/misc/cxl/cxl.h @@ -403,6 +403,18 @@ struct cxl_afu { bool enabled; }; +/* AFU refcount management */ +static inline struct cxl_afu *cxl_afu_get(struct cxl_afu *afu) +{ + + return (get_device(&afu->dev) == NULL) ? NULL : afu; +} + +static inline void cxl_afu_put(struct cxl_afu *afu) +{ + put_device(&afu->dev); +} + struct cxl_irq_name { struct list_head list; @@ -433,6 +445,9 @@ struct cxl_context { unsigned int sst_size, sst_lru; wait_queue_head_t wq; + /* pid of the group leader associated with the pid */ + struct pid *glpid; + /* use mm context associated with this pid for ds faults */ struct pid *pid; spinlock_t lock; /* Protects pending_irq_mask, pending_fault and fault_addr */ /* Only used in PR mode */ diff --git a/drivers/misc/cxl/fault.c b/drivers/misc/cxl/fault.c index 25a5418c5..81c3f75b7 100644 --- a/drivers/misc/cxl/fault.c +++ b/drivers/misc/cxl/fault.c @@ -166,13 +166,92 @@ static void cxl_handle_page_fault(struct cxl_context *ctx, cxl_ack_irq(ctx, CXL_PSL_TFC_An_R, 0); } +/* + * Returns the mm_struct corresponding to the context ctx via ctx->pid + * In case the task has exited we use the task group leader accessible + * via ctx->glpid to find the next task in the thread group that has a + * valid mm_struct associated with it. If a task with valid mm_struct + * is found the ctx->pid is updated to use the task struct for subsequent + * translations. In case no valid mm_struct is found in the task group to + * service the fault a NULL is returned. + */ +static struct mm_struct *get_mem_context(struct cxl_context *ctx) +{ + struct task_struct *task = NULL; + struct mm_struct *mm = NULL; + struct pid *old_pid = ctx->pid; + + if (old_pid == NULL) { + pr_warn("%s: Invalid context for pe=%d\n", + __func__, ctx->pe); + return NULL; + } + + task = get_pid_task(old_pid, PIDTYPE_PID); + + /* + * pid_alive may look racy but this saves us from costly + * get_task_mm when the task is a zombie. In worst case + * we may think a task is alive, which is about to die + * but get_task_mm will return NULL. + */ + if (task != NULL && pid_alive(task)) + mm = get_task_mm(task); + + /* release the task struct that was taken earlier */ + if (task) + put_task_struct(task); + else + pr_devel("%s: Context owning pid=%i for pe=%i dead\n", + __func__, pid_nr(old_pid), ctx->pe); + + /* + * If we couldn't find the mm context then use the group + * leader to iterate over the task group and find a task + * that gives us mm_struct. + */ + if (unlikely(mm == NULL && ctx->glpid != NULL)) { + + rcu_read_lock(); + task = pid_task(ctx->glpid, PIDTYPE_PID); + if (task) + do { + mm = get_task_mm(task); + if (mm) { + ctx->pid = get_task_pid(task, + PIDTYPE_PID); + break; + } + task = next_thread(task); + } while (task && !thread_group_leader(task)); + rcu_read_unlock(); + + /* check if we switched pid */ + if (ctx->pid != old_pid) { + if (mm) + pr_devel("%s:pe=%i switch pid %i->%i\n", + __func__, ctx->pe, pid_nr(old_pid), + pid_nr(ctx->pid)); + else + pr_devel("%s:Cannot find mm for pid=%i\n", + __func__, pid_nr(old_pid)); + + /* drop the reference to older pid */ + put_pid(old_pid); + } + } + + return mm; +} + + + void cxl_handle_fault(struct work_struct *fault_work) { struct cxl_context *ctx = container_of(fault_work, struct cxl_context, fault_work); u64 dsisr = ctx->dsisr; u64 dar = ctx->dar; - struct task_struct *task = NULL; struct mm_struct *mm = NULL; if (cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An) != dsisr || @@ -195,17 +274,17 @@ void cxl_handle_fault(struct work_struct *fault_work) "DSISR: %#llx DAR: %#llx\n", ctx->pe, dsisr, dar); if (!ctx->kernel) { - if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { - pr_devel("cxl_handle_fault unable to get task %i\n", - pid_nr(ctx->pid)); + + mm = get_mem_context(ctx); + /* indicates all the thread in task group have exited */ + if (mm == NULL) { + pr_devel("%s: unable to get mm for pe=%d pid=%i\n", + __func__, ctx->pe, pid_nr(ctx->pid)); cxl_ack_ae(ctx); return; - } - if (!(mm = get_task_mm(task))) { - pr_devel("cxl_handle_fault unable to get mm %i\n", - pid_nr(ctx->pid)); - cxl_ack_ae(ctx); - goto out; + } else { + pr_devel("Handling page fault for pe=%d pid=%i\n", + ctx->pe, pid_nr(ctx->pid)); } } @@ -218,33 +297,22 @@ void cxl_handle_fault(struct work_struct *fault_work) if (mm) mmput(mm); -out: - if (task) - put_task_struct(task); } static void cxl_prefault_one(struct cxl_context *ctx, u64 ea) { - int rc; - struct task_struct *task; struct mm_struct *mm; - if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { - pr_devel("cxl_prefault_one unable to get task %i\n", - pid_nr(ctx->pid)); - return; - } - if (!(mm = get_task_mm(task))) { + mm = get_mem_context(ctx); + if (mm == NULL) { pr_devel("cxl_prefault_one unable to get mm %i\n", pid_nr(ctx->pid)); - put_task_struct(task); return; } - rc = cxl_fault_segment(ctx, mm, ea); + cxl_fault_segment(ctx, mm, ea); mmput(mm); - put_task_struct(task); } static u64 next_segment(u64 ea, u64 vsid) @@ -263,18 +331,13 @@ static void cxl_prefault_vma(struct cxl_context *ctx) struct copro_slb slb; struct vm_area_struct *vma; int rc; - struct task_struct *task; struct mm_struct *mm; - if (!(task = get_pid_task(ctx->pid, PIDTYPE_PID))) { - pr_devel("cxl_prefault_vma unable to get task %i\n", - pid_nr(ctx->pid)); - return; - } - if (!(mm = get_task_mm(task))) { + mm = get_mem_context(ctx); + if (mm == NULL) { pr_devel("cxl_prefault_vm unable to get mm %i\n", pid_nr(ctx->pid)); - goto out1; + return; } down_read(&mm->mmap_sem); @@ -295,8 +358,6 @@ static void cxl_prefault_vma(struct cxl_context *ctx) up_read(&mm->mmap_sem); mmput(mm); -out1: - put_task_struct(task); } void cxl_prefault(struct cxl_context *ctx, u64 wed) diff --git a/drivers/misc/cxl/file.c b/drivers/misc/cxl/file.c index 7ccd2998b..783337d22 100644 --- a/drivers/misc/cxl/file.c +++ b/drivers/misc/cxl/file.c @@ -67,7 +67,13 @@ static int __afu_open(struct inode *inode, struct file *file, bool master) spin_unlock(&adapter->afu_list_lock); goto err_put_adapter; } - get_device(&afu->dev); + + /* + * taking a ref to the afu so that it doesn't go away + * for rest of the function. This ref is released before + * we return. + */ + cxl_afu_get(afu); spin_unlock(&adapter->afu_list_lock); if (!afu->current_mode) @@ -90,13 +96,12 @@ static int __afu_open(struct inode *inode, struct file *file, bool master) file->private_data = ctx; cxl_ctx_get(); - /* Our ref on the AFU will now hold the adapter */ - put_device(&adapter->dev); - - return 0; + /* indicate success */ + rc = 0; err_put_afu: - put_device(&afu->dev); + /* release the ref taken earlier */ + cxl_afu_put(afu); err_put_adapter: put_device(&adapter->dev); return rc; @@ -131,8 +136,6 @@ int afu_release(struct inode *inode, struct file *file) mutex_unlock(&ctx->mapping_lock); } - put_device(&ctx->afu->dev); - /* * At this this point all bottom halfs have finished and we should be * getting no more IRQs from the hardware for this context. Once it's @@ -198,8 +201,12 @@ static long afu_ioctl_start_work(struct cxl_context *ctx, * where a process (master, some daemon, etc) has opened the chardev on * behalf of another process, so the AFU's mm gets bound to the process * that performs this ioctl and not the process that opened the file. + * Also we grab the PID of the group leader so that if the task that + * has performed the attach operation exits the mm context of the + * process is still accessible. */ - ctx->pid = get_pid(get_task_pid(current, PIDTYPE_PID)); + ctx->pid = get_task_pid(current, PIDTYPE_PID); + ctx->glpid = get_task_pid(current->group_leader, PIDTYPE_PID); trace_cxl_attach(ctx, work.work_element_descriptor, work.num_interrupts, amr); diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index be2c8e248..0c6c17a1c 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -138,6 +138,7 @@ static const struct pci_device_id cxl_pci_tbl[] = { { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0477), }, { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x044b), }, { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x04cf), }, + { PCI_DEVICE(PCI_VENDOR_ID_IBM, 0x0601), }, { PCI_DEVICE_CLASS(0x120000, ~0), }, { } |