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/*
* Copyright 2014 IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/bitmap.h>
#include <linux/sched.h>
#include <linux/pid.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/debugfs.h>
#include <linux/slab.h>
#include <linux/idr.h>
#include <asm/cputable.h>
#include <asm/current.h>
#include <asm/copro.h>
#include "cxl.h"
/*
* Allocates space for a CXL context.
*/
struct cxl_context *cxl_context_alloc(void)
{
return kzalloc(sizeof(struct cxl_context), GFP_KERNEL);
}
/*
* Initialises a CXL context.
*/
int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master)
{
int i;
spin_lock_init(&ctx->sste_lock);
ctx->afu = afu;
ctx->master = master;
ctx->pid = NULL; /* Set in start work ioctl */
/*
* Allocate the segment table before we put it in the IDR so that we
* can always access it when dereferenced from IDR. For the same
* reason, the segment table is only destroyed after the context is
* removed from the IDR. Access to this in the IOCTL is protected by
* Linux filesytem symantics (can't IOCTL until open is complete).
*/
i = cxl_alloc_sst(ctx);
if (i)
return i;
INIT_WORK(&ctx->fault_work, cxl_handle_fault);
init_waitqueue_head(&ctx->wq);
spin_lock_init(&ctx->lock);
ctx->irq_bitmap = NULL;
ctx->pending_irq = false;
ctx->pending_fault = false;
ctx->pending_afu_err = false;
/*
* When we have to destroy all contexts in cxl_context_detach_all() we
* end up with afu_release_irqs() called from inside a
* idr_for_each_entry(). Hence we need to make sure that anything
* dereferenced from this IDR is ok before we allocate the IDR here.
* This clears out the IRQ ranges to ensure this.
*/
for (i = 0; i < CXL_IRQ_RANGES; i++)
ctx->irqs.range[i] = 0;
mutex_init(&ctx->status_mutex);
ctx->status = OPENED;
/*
* Allocating IDR! We better make sure everything's setup that
* dereferences from it.
*/
idr_preload(GFP_KERNEL);
spin_lock(&afu->contexts_lock);
i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
ctx->afu->num_procs, GFP_NOWAIT);
spin_unlock(&afu->contexts_lock);
idr_preload_end();
if (i < 0)
return i;
ctx->pe = i;
ctx->elem = &ctx->afu->spa[i];
ctx->pe_inserted = false;
return 0;
}
/*
* Map a per-context mmio space into the given vma.
*/
int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
{
u64 len = vma->vm_end - vma->vm_start;
len = min(len, ctx->psn_size);
if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
return vm_iomap_memory(vma, ctx->afu->psn_phys, ctx->afu->adapter->ps_size);
}
/* make sure there is a valid per process space for this AFU */
if ((ctx->master && !ctx->afu->psa) || (!ctx->afu->pp_psa)) {
pr_devel("AFU doesn't support mmio space\n");
return -EINVAL;
}
/* Can't mmap until the AFU is enabled */
if (!ctx->afu->enabled)
return -EBUSY;
pr_devel("%s: mmio physical: %llx pe: %i master:%i\n", __func__,
ctx->psn_phys, ctx->pe , ctx->master);
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
return vm_iomap_memory(vma, ctx->psn_phys, len);
}
/*
* Detach a context from the hardware. This disables interrupts and doesn't
* return until all outstanding interrupts for this context have completed. The
* hardware should no longer access *ctx after this has returned.
*/
static void __detach_context(struct cxl_context *ctx)
{
enum cxl_context_status status;
mutex_lock(&ctx->status_mutex);
status = ctx->status;
ctx->status = CLOSED;
mutex_unlock(&ctx->status_mutex);
if (status != STARTED)
return;
WARN_ON(cxl_detach_process(ctx));
afu_release_irqs(ctx);
flush_work(&ctx->fault_work); /* Only needed for dedicated process */
wake_up_all(&ctx->wq);
}
/*
* Detach the given context from the AFU. This doesn't actually
* free the context but it should stop the context running in hardware
* (ie. prevent this context from generating any further interrupts
* so that it can be freed).
*/
void cxl_context_detach(struct cxl_context *ctx)
{
__detach_context(ctx);
}
/*
* Detach all contexts on the given AFU.
*/
void cxl_context_detach_all(struct cxl_afu *afu)
{
struct cxl_context *ctx;
int tmp;
rcu_read_lock();
idr_for_each_entry(&afu->contexts_idr, ctx, tmp)
/*
* Anything done in here needs to be setup before the IDR is
* created and torn down after the IDR removed
*/
__detach_context(ctx);
rcu_read_unlock();
}
void cxl_context_free(struct cxl_context *ctx)
{
spin_lock(&ctx->afu->contexts_lock);
idr_remove(&ctx->afu->contexts_idr, ctx->pe);
spin_unlock(&ctx->afu->contexts_lock);
synchronize_rcu();
free_page((u64)ctx->sstp);
ctx->sstp = NULL;
put_pid(ctx->pid);
kfree(ctx);
}
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