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7b8ad495d5
Presently when a user-space process issues CXL_IOCTL_START_WORK ioctl we store the pid of the current task_struct and use it to get pointer to the mm_struct of the process, while processing page or segment faults from the capi card. However this causes issues when the thread that had originally issued the start-work ioctl exits in which case the stored pid is no more valid and the cxl driver is unable to handle faults as the mm_struct corresponding to process is no more accessible. This patch fixes this issue by using the mm_struct of the next alive task in the thread group. This is done by iterating over all the tasks in the thread group starting from thread group leader and calling get_task_mm on each one of them. When a valid mm_struct is obtained the pid of the associated task is stored in the context replacing the exiting one for handling future faults. The patch introduces a new function named get_mem_context that checks if the current task pointed to by ctx->pid is dead? If yes it performs the steps described above. Also a new variable cxl_context.glpid is introduced which stores the pid of the thread group leader associated with the context owning task. Reported-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Reported-by: Frank Haverkamp <HAVERKAM@de.ibm.com> Suggested-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Reviewed-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com> Reviewed-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
366 lines
7.7 KiB
C
366 lines
7.7 KiB
C
/*
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* Copyright 2014 IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/pci.h>
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#include <linux/slab.h>
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#include <linux/anon_inodes.h>
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#include <linux/file.h>
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#include <misc/cxl.h>
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#include <linux/fs.h>
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#include "cxl.h"
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struct cxl_context *cxl_dev_context_init(struct pci_dev *dev)
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{
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struct address_space *mapping;
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struct cxl_afu *afu;
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struct cxl_context *ctx;
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int rc;
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afu = cxl_pci_to_afu(dev);
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ctx = cxl_context_alloc();
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if (IS_ERR(ctx)) {
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rc = PTR_ERR(ctx);
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goto err_dev;
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}
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ctx->kernelapi = true;
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/*
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* Make our own address space since we won't have one from the
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* filesystem like the user api has, and even if we do associate a file
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* with this context we don't want to use the global anonymous inode's
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* address space as that can invalidate unrelated users:
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*/
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mapping = kmalloc(sizeof(struct address_space), GFP_KERNEL);
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if (!mapping) {
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rc = -ENOMEM;
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goto err_ctx;
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}
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address_space_init_once(mapping);
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/* Make it a slave context. We can promote it later? */
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rc = cxl_context_init(ctx, afu, false, mapping);
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if (rc)
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goto err_mapping;
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cxl_assign_psn_space(ctx);
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return ctx;
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err_mapping:
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kfree(mapping);
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err_ctx:
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kfree(ctx);
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err_dev:
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return ERR_PTR(rc);
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}
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EXPORT_SYMBOL_GPL(cxl_dev_context_init);
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struct cxl_context *cxl_get_context(struct pci_dev *dev)
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{
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return dev->dev.archdata.cxl_ctx;
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}
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EXPORT_SYMBOL_GPL(cxl_get_context);
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struct device *cxl_get_phys_dev(struct pci_dev *dev)
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{
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struct cxl_afu *afu;
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afu = cxl_pci_to_afu(dev);
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return afu->adapter->dev.parent;
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}
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EXPORT_SYMBOL_GPL(cxl_get_phys_dev);
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int cxl_release_context(struct cxl_context *ctx)
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{
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if (ctx->status >= STARTED)
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return -EBUSY;
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cxl_context_free(ctx);
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return 0;
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}
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EXPORT_SYMBOL_GPL(cxl_release_context);
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int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
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{
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if (num == 0)
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num = ctx->afu->pp_irqs;
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return afu_allocate_irqs(ctx, num);
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}
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EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
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void cxl_free_afu_irqs(struct cxl_context *ctx)
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{
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afu_irq_name_free(ctx);
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cxl_release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
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}
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EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
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static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
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{
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__u16 range;
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int r;
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WARN_ON(num == 0);
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for (r = 0; r < CXL_IRQ_RANGES; r++) {
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range = ctx->irqs.range[r];
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if (num < range) {
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return ctx->irqs.offset[r] + num;
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}
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num -= range;
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}
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return 0;
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}
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int cxl_map_afu_irq(struct cxl_context *ctx, int num,
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irq_handler_t handler, void *cookie, char *name)
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{
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irq_hw_number_t hwirq;
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/*
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* Find interrupt we are to register.
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*/
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hwirq = cxl_find_afu_irq(ctx, num);
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if (!hwirq)
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return -ENOENT;
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return cxl_map_irq(ctx->afu->adapter, hwirq, handler, cookie, name);
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}
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EXPORT_SYMBOL_GPL(cxl_map_afu_irq);
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void cxl_unmap_afu_irq(struct cxl_context *ctx, int num, void *cookie)
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{
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irq_hw_number_t hwirq;
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unsigned int virq;
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hwirq = cxl_find_afu_irq(ctx, num);
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if (!hwirq)
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return;
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virq = irq_find_mapping(NULL, hwirq);
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if (virq)
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cxl_unmap_irq(virq, cookie);
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}
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EXPORT_SYMBOL_GPL(cxl_unmap_afu_irq);
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/*
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* Start a context
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* Code here similar to afu_ioctl_start_work().
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*/
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int cxl_start_context(struct cxl_context *ctx, u64 wed,
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struct task_struct *task)
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{
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int rc = 0;
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bool kernel = true;
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pr_devel("%s: pe: %i\n", __func__, ctx->pe);
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mutex_lock(&ctx->status_mutex);
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if (ctx->status == STARTED)
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goto out; /* already started */
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if (task) {
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ctx->pid = get_task_pid(task, PIDTYPE_PID);
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ctx->glpid = get_task_pid(task->group_leader, PIDTYPE_PID);
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kernel = false;
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}
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cxl_ctx_get();
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if ((rc = cxl_attach_process(ctx, kernel, wed , 0))) {
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put_pid(ctx->pid);
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cxl_ctx_put();
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goto out;
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}
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ctx->status = STARTED;
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out:
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mutex_unlock(&ctx->status_mutex);
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return rc;
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}
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EXPORT_SYMBOL_GPL(cxl_start_context);
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int cxl_process_element(struct cxl_context *ctx)
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{
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return ctx->pe;
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}
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EXPORT_SYMBOL_GPL(cxl_process_element);
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/* Stop a context. Returns 0 on success, otherwise -Errno */
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int cxl_stop_context(struct cxl_context *ctx)
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{
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return __detach_context(ctx);
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}
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EXPORT_SYMBOL_GPL(cxl_stop_context);
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void cxl_set_master(struct cxl_context *ctx)
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{
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ctx->master = true;
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cxl_assign_psn_space(ctx);
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}
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EXPORT_SYMBOL_GPL(cxl_set_master);
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/* wrappers around afu_* file ops which are EXPORTED */
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int cxl_fd_open(struct inode *inode, struct file *file)
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{
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return afu_open(inode, file);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_open);
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int cxl_fd_release(struct inode *inode, struct file *file)
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{
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return afu_release(inode, file);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_release);
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long cxl_fd_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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{
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return afu_ioctl(file, cmd, arg);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_ioctl);
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int cxl_fd_mmap(struct file *file, struct vm_area_struct *vm)
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{
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return afu_mmap(file, vm);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_mmap);
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unsigned int cxl_fd_poll(struct file *file, struct poll_table_struct *poll)
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{
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return afu_poll(file, poll);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_poll);
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ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
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loff_t *off)
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{
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return afu_read(file, buf, count, off);
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}
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EXPORT_SYMBOL_GPL(cxl_fd_read);
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#define PATCH_FOPS(NAME) if (!fops->NAME) fops->NAME = afu_fops.NAME
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/* Get a struct file and fd for a context and attach the ops */
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struct file *cxl_get_fd(struct cxl_context *ctx, struct file_operations *fops,
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int *fd)
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{
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struct file *file;
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int rc, flags, fdtmp;
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flags = O_RDWR | O_CLOEXEC;
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/* This code is similar to anon_inode_getfd() */
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rc = get_unused_fd_flags(flags);
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if (rc < 0)
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return ERR_PTR(rc);
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fdtmp = rc;
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/*
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* Patch the file ops. Needs to be careful that this is rentrant safe.
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*/
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if (fops) {
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PATCH_FOPS(open);
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PATCH_FOPS(poll);
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PATCH_FOPS(read);
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PATCH_FOPS(release);
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PATCH_FOPS(unlocked_ioctl);
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PATCH_FOPS(compat_ioctl);
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PATCH_FOPS(mmap);
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} else /* use default ops */
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fops = (struct file_operations *)&afu_fops;
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file = anon_inode_getfile("cxl", fops, ctx, flags);
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if (IS_ERR(file))
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goto err_fd;
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file->f_mapping = ctx->mapping;
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*fd = fdtmp;
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return file;
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err_fd:
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put_unused_fd(fdtmp);
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return NULL;
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}
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EXPORT_SYMBOL_GPL(cxl_get_fd);
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struct cxl_context *cxl_fops_get_context(struct file *file)
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{
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return file->private_data;
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}
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EXPORT_SYMBOL_GPL(cxl_fops_get_context);
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int cxl_start_work(struct cxl_context *ctx,
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struct cxl_ioctl_start_work *work)
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{
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int rc;
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/* code taken from afu_ioctl_start_work */
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if (!(work->flags & CXL_START_WORK_NUM_IRQS))
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work->num_interrupts = ctx->afu->pp_irqs;
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else if ((work->num_interrupts < ctx->afu->pp_irqs) ||
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(work->num_interrupts > ctx->afu->irqs_max)) {
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return -EINVAL;
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}
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rc = afu_register_irqs(ctx, work->num_interrupts);
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if (rc)
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return rc;
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rc = cxl_start_context(ctx, work->work_element_descriptor, current);
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if (rc < 0) {
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afu_release_irqs(ctx, ctx);
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return rc;
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}
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return 0;
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}
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EXPORT_SYMBOL_GPL(cxl_start_work);
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void __iomem *cxl_psa_map(struct cxl_context *ctx)
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{
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struct cxl_afu *afu = ctx->afu;
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int rc;
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rc = cxl_afu_check_and_enable(afu);
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if (rc)
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return NULL;
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pr_devel("%s: psn_phys%llx size:%llx\n",
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__func__, afu->psn_phys, afu->adapter->ps_size);
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return ioremap(ctx->psn_phys, ctx->psn_size);
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}
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EXPORT_SYMBOL_GPL(cxl_psa_map);
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void cxl_psa_unmap(void __iomem *addr)
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{
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iounmap(addr);
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}
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EXPORT_SYMBOL_GPL(cxl_psa_unmap);
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int cxl_afu_reset(struct cxl_context *ctx)
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{
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struct cxl_afu *afu = ctx->afu;
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int rc;
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rc = __cxl_afu_reset(afu);
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if (rc)
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return rc;
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return cxl_afu_check_and_enable(afu);
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}
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EXPORT_SYMBOL_GPL(cxl_afu_reset);
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void cxl_perst_reloads_same_image(struct cxl_afu *afu,
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bool perst_reloads_same_image)
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{
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afu->adapter->perst_same_image = perst_reloads_same_image;
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}
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EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
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