![Ian Munsie](/assets/img/avatar_default.png)
The cxl user api uses the address_space associated with the file when we need to force unmap all cxl mmap regions (e.g. on eeh, driver detach, etc). Currently, contexts allocated through the kernel api do not do this and instead skip the mmap invalidation, potentially allowing them to poke at the hardware after such an event, which may cause all sorts of trouble. This patch allocates an address_space for cxl contexts allocated through the kernel api so that the same invalidate path will for these contexts as well. We don't use the anonymous inode's address_space, as doing so could invalidate any mmaps of completely unrelated drivers using anonymous file descriptors. This patch also introduces a kernelapi flag, so we know when freeing the context if the address_space was allocated by us and needs to be freed. Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
288 lines
7.3 KiB
C
288 lines
7.3 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/module.h>
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#include <linux/kernel.h>
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#include <linux/bitmap.h>
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#include <linux/sched.h>
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#include <linux/pid.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/debugfs.h>
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#include <linux/slab.h>
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#include <linux/idr.h>
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#include <asm/cputable.h>
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#include <asm/current.h>
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#include <asm/copro.h>
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#include "cxl.h"
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/*
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* Allocates space for a CXL context.
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*/
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struct cxl_context *cxl_context_alloc(void)
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{
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return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
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}
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/*
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* Initialises a CXL context.
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*/
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int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master,
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struct address_space *mapping)
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{
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int i;
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spin_lock_init(&ctx->sste_lock);
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ctx->afu = afu;
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ctx->master = master;
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ctx->pid = NULL; /* Set in start work ioctl */
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mutex_init(&ctx->mapping_lock);
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ctx->mapping = mapping;
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/*
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* Allocate the segment table before we put it in the IDR so that we
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* can always access it when dereferenced from IDR. For the same
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* reason, the segment table is only destroyed after the context is
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* removed from the IDR. Access to this in the IOCTL is protected by
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* Linux filesytem symantics (can't IOCTL until open is complete).
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*/
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i = cxl_alloc_sst(ctx);
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if (i)
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return i;
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INIT_WORK(&ctx->fault_work, cxl_handle_fault);
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init_waitqueue_head(&ctx->wq);
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spin_lock_init(&ctx->lock);
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ctx->irq_bitmap = NULL;
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ctx->pending_irq = false;
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ctx->pending_fault = false;
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ctx->pending_afu_err = false;
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/*
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* When we have to destroy all contexts in cxl_context_detach_all() we
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* end up with afu_release_irqs() called from inside a
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* idr_for_each_entry(). Hence we need to make sure that anything
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* dereferenced from this IDR is ok before we allocate the IDR here.
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* This clears out the IRQ ranges to ensure this.
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*/
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for (i = 0; i < CXL_IRQ_RANGES; i++)
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ctx->irqs.range[i] = 0;
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mutex_init(&ctx->status_mutex);
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ctx->status = OPENED;
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/*
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* Allocating IDR! We better make sure everything's setup that
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* dereferences from it.
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*/
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mutex_lock(&afu->contexts_lock);
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idr_preload(GFP_KERNEL);
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i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
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ctx->afu->num_procs, GFP_NOWAIT);
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idr_preload_end();
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mutex_unlock(&afu->contexts_lock);
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if (i < 0)
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return i;
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ctx->pe = i;
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ctx->elem = &ctx->afu->spa[i];
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ctx->pe_inserted = false;
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return 0;
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}
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static int cxl_mmap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
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struct cxl_context *ctx = vma->vm_file->private_data;
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unsigned long address = (unsigned long)vmf->virtual_address;
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u64 area, offset;
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offset = vmf->pgoff << PAGE_SHIFT;
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pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
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__func__, ctx->pe, address, offset);
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if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
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area = ctx->afu->psn_phys;
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if (offset >= ctx->afu->adapter->ps_size)
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return VM_FAULT_SIGBUS;
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} else {
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area = ctx->psn_phys;
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if (offset >= ctx->psn_size)
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return VM_FAULT_SIGBUS;
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}
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mutex_lock(&ctx->status_mutex);
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if (ctx->status != STARTED) {
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mutex_unlock(&ctx->status_mutex);
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pr_devel("%s: Context not started, failing problem state access\n", __func__);
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if (ctx->mmio_err_ff) {
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if (!ctx->ff_page) {
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ctx->ff_page = alloc_page(GFP_USER);
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if (!ctx->ff_page)
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return VM_FAULT_OOM;
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memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
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}
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get_page(ctx->ff_page);
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vmf->page = ctx->ff_page;
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vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
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return 0;
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}
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return VM_FAULT_SIGBUS;
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}
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vm_insert_pfn(vma, address, (area + offset) >> PAGE_SHIFT);
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mutex_unlock(&ctx->status_mutex);
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return VM_FAULT_NOPAGE;
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}
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static const struct vm_operations_struct cxl_mmap_vmops = {
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.fault = cxl_mmap_fault,
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};
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/*
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* Map a per-context mmio space into the given vma.
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*/
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int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
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{
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u64 start = vma->vm_pgoff << PAGE_SHIFT;
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u64 len = vma->vm_end - vma->vm_start;
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if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
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if (start + len > ctx->afu->adapter->ps_size)
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return -EINVAL;
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} else {
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if (start + len > ctx->psn_size)
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return -EINVAL;
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}
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if (ctx->afu->current_mode != CXL_MODE_DEDICATED) {
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/* make sure there is a valid per process space for this AFU */
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if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
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pr_devel("AFU doesn't support mmio space\n");
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return -EINVAL;
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}
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/* Can't mmap until the AFU is enabled */
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if (!ctx->afu->enabled)
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return -EBUSY;
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}
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pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
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ctx->psn_phys, ctx->pe , ctx->master);
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vma->vm_flags |= VM_IO | VM_PFNMAP;
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vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
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vma->vm_ops = &cxl_mmap_vmops;
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return 0;
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}
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/*
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* Detach a context from the hardware. This disables interrupts and doesn't
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* return until all outstanding interrupts for this context have completed. The
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* hardware should no longer access *ctx after this has returned.
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*/
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int __detach_context(struct cxl_context *ctx)
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{
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enum cxl_context_status status;
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mutex_lock(&ctx->status_mutex);
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status = ctx->status;
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ctx->status = CLOSED;
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mutex_unlock(&ctx->status_mutex);
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if (status != STARTED)
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return -EBUSY;
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/* Only warn if we detached while the link was OK.
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* If detach fails when hw is down, we don't care.
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*/
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WARN_ON(cxl_detach_process(ctx) &&
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cxl_adapter_link_ok(ctx->afu->adapter));
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flush_work(&ctx->fault_work); /* Only needed for dedicated process */
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put_pid(ctx->pid);
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cxl_ctx_put();
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return 0;
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}
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/*
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* Detach the given context from the AFU. This doesn't actually
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* free the context but it should stop the context running in hardware
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* (ie. prevent this context from generating any further interrupts
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* so that it can be freed).
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*/
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void cxl_context_detach(struct cxl_context *ctx)
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{
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int rc;
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rc = __detach_context(ctx);
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if (rc)
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return;
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afu_release_irqs(ctx, ctx);
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wake_up_all(&ctx->wq);
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}
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/*
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* Detach all contexts on the given AFU.
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*/
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void cxl_context_detach_all(struct cxl_afu *afu)
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{
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struct cxl_context *ctx;
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int tmp;
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mutex_lock(&afu->contexts_lock);
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idr_for_each_entry(&afu->contexts_idr, ctx, tmp) {
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/*
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* Anything done in here needs to be setup before the IDR is
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* created and torn down after the IDR removed
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*/
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cxl_context_detach(ctx);
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/*
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* We are force detaching - remove any active PSA mappings so
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* userspace cannot interfere with the card if it comes back.
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* Easiest way to exercise this is to unbind and rebind the
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* driver via sysfs while it is in use.
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*/
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mutex_lock(&ctx->mapping_lock);
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if (ctx->mapping)
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unmap_mapping_range(ctx->mapping, 0, 0, 1);
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mutex_unlock(&ctx->mapping_lock);
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}
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mutex_unlock(&afu->contexts_lock);
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}
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static void reclaim_ctx(struct rcu_head *rcu)
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{
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struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
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free_page((u64)ctx->sstp);
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if (ctx->ff_page)
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__free_page(ctx->ff_page);
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ctx->sstp = NULL;
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if (ctx->kernelapi)
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kfree(ctx->mapping);
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kfree(ctx);
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}
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void cxl_context_free(struct cxl_context *ctx)
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{
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mutex_lock(&ctx->afu->contexts_lock);
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idr_remove(&ctx->afu->contexts_idr, ctx->pe);
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mutex_unlock(&ctx->afu->contexts_lock);
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call_rcu(&ctx->rcu, reclaim_ctx);
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}
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