// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2014 IBM Corp.
*/
#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 <linux/sched/mm.h>
#include <linux/mmu_context.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;
ctx->afu = afu;
ctx->master = master;
ctx->pid = NULL; /* Set in start work ioctl */
mutex_init(&ctx->mapping_lock);
ctx->mapping = NULL;
ctx->tidr = 0;
ctx->assign_tidr = false;
if (cxl_is_power8()) {
spin_lock_init(&ctx->sste_lock);
/*
* 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 filesystem semantics (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;
INIT_LIST_HEAD(&ctx->irq_names);
/*
* 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.
*/
mutex_lock(&afu->contexts_lock);
idr_preload(GFP_KERNEL);
i = idr_alloc(&ctx->afu->contexts_idr, ctx, 0,
ctx->afu->num_procs, GFP_NOWAIT);
idr_preload_end();
mutex_unlock(&afu->contexts_lock);
if (i < 0)
return i;
ctx->pe = i;
if (cpu_has_feature(CPU_FTR_HVMODE)) {
ctx->elem = &ctx->afu->native->spa[i];
ctx->external_pe = ctx->pe;
} else {
ctx->external_pe = -1; /* assigned when attaching */
}
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;
}
void cxl_context_set_mapping(struct cxl_context *ctx,
struct address_space *mapping)
{
mutex_lock(&ctx->mapping_lock);
ctx->mapping = mapping;
mutex_unlock(&ctx->mapping_lock);
}
static vm_fault_t cxl_mmap_fault(struct vm_fault *vmf)
{
struct vm_area_struct *vma = vmf->vma;
struct cxl_context *ctx = vma->vm_file->private_data;
u64 area, offset;
vm_fault_t ret;
offset = vmf->pgoff << PAGE_SHIFT;
pr_devel("%s: pe: %i address: 0x%lx offset: 0x%llx\n",
__func__, ctx->pe, vmf->address, offset);
if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
area = ctx->afu->psn_phys;
if (offset >= ctx->afu->adapter->ps_size)
return VM_FAULT_SIGBUS;
} else {
area = ctx->psn_phys;
if (offset >= ctx->psn_size)
return VM_FAULT_SIGBUS;
}
mutex_lock(&ctx->status_mutex);
if (ctx->status != STARTED) {
mutex_unlock(&ctx->status_mutex);
pr_devel("%s: Context not started, failing problem state access\n", __func__);
if (ctx->mmio_err_ff) {
if (!ctx->ff_page) {
ctx->ff_page = alloc_page(GFP_USER);
if (!ctx->ff_page)
return VM_FAULT_OOM;
memset(page_address(ctx->ff_page), 0xff, PAGE_SIZE);
}
get_page(ctx->ff_page);
vmf->page = ctx->ff_page;
vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
return 0;
}
return VM_FAULT_SIGBUS;
}
ret = vmf_insert_pfn(vma, vmf->address, (area + offset) >> PAGE_SHIFT);
mutex_unlock(&ctx->status_mutex);
return ret;
}
static const struct vm_operations_struct cxl_mmap_vmops = {
.fault = cxl_mmap_fault,
};
/*
* Map a per-context mmio space into the given vma.
*/
int cxl_context_iomap(struct cxl_context *ctx, struct vm_area_struct *vma)
{
u64 start = vma->vm_pgoff << PAGE_SHIFT;
u64 len = vma->vm_end - vma->vm_start;
if (ctx->afu->current_mode == CXL_MODE_DEDICATED) {
if (start + len > ctx->afu->adapter->ps_size)
return -EINVAL;
if (cxl_is_power9()) {
/*
* Make sure there is a valid problem state
* area space for this AFU.
*/
if (ctx->master && !ctx->afu->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;
}
} else {
if (start + len > ctx->psn_size)
return -EINVAL;
/* 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);
vm_flags_set(vma, VM_IO | VM_PFNMAP);
vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
vma->vm_ops = &cxl_mmap_vmops;
return 0;
}
/*
* 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.
*/
int __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 -EBUSY;
/* Only warn if we detached while the link was OK.
* If detach fails when hw is down, we don't care.
*/
WARN_ON(cxl_ops->detach_process(ctx) &&
cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));
flush_work(&ctx->fault_work); /* Only needed for dedicated process */
/*
* Wait until no further interrupts are presented by the PSL
* for this context.
*/
if (cxl_ops->irq_wait)
cxl_ops->irq_wait(ctx);
/* release the reference to the group leader and mm handling pid */
put_pid(ctx->pid);
cxl_ctx_put();
/* Decrease the attached context count on the adapter */
cxl_adapter_context_put(ctx->afu->adapter);
/* Decrease the mm count on the context */
cxl_context_mm_count_put(ctx);
if (ctx->mm)
mm_context_remove_copro(ctx->mm);
ctx->mm = NULL;
return 0;
}
/*
* 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)
{
int rc;
rc = __detach_context(ctx);
if (rc)
return;
afu_release_irqs(ctx, ctx);
wake_up_all(&ctx->wq);
}
/*
* Detach all contexts on the given AFU.
*/
void cxl_context_detach_all(struct cxl_afu *afu)
{
struct cxl_context *ctx;
int tmp;
mutex_lock(&afu->contexts_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
*/
cxl_context_detach(ctx);
/*
* We are force detaching - remove any active PSA mappings so
* userspace cannot interfere with the card if it comes back.
* Easiest way to exercise this is to unbind and rebind the
* driver via sysfs while it is in use.
*/
mutex_lock(&ctx->mapping_lock);
if (ctx->mapping)
unmap_mapping_range(ctx->mapping, 0, 0, 1);
mutex_unlock(&ctx->mapping_lock);
}
mutex_unlock(&afu->contexts_lock);
}
static void reclaim_ctx(struct rcu_head *rcu)
{
struct cxl_context *ctx = container_of(rcu, struct cxl_context, rcu);
if (cxl_is_power8())
free_page((u64)ctx->sstp);
if (ctx->ff_page)
__free_page(ctx->ff_page);
ctx->sstp = NULL;
bitmap_free(ctx->irq_bitmap);
/* Drop ref to the afu device taken during cxl_context_init */
cxl_afu_put(ctx->afu);
kfree(ctx);
}
void cxl_context_free(struct cxl_context *ctx)
{
if (ctx->kernelapi && ctx->mapping)
cxl_release_mapping(ctx);
mutex_lock(&ctx->afu->contexts_lock);
idr_remove(&ctx->afu->contexts_idr, ctx->pe);
mutex_unlock(&ctx->afu->contexts_lock);
call_rcu(&ctx->rcu, reclaim_ctx);
}
void cxl_context_mm_count_get(struct cxl_context *ctx)
{
if (ctx->mm)
mmgrab(ctx->mm);
}
void cxl_context_mm_count_put(struct cxl_context *ctx)
{
if (ctx->mm)
mmdrop(ctx->mm);
}
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