// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2017 IBM Corp.
*/
#include <linux/hugetlb.h>
#include <linux/sched/mm.h>
#include <asm/opal-api.h>
#include <asm/pnv-pci.h>
#include <misc/cxllib.h>
#include "cxl.h"
#define CXL_INVALID_DRA ~0ull
#define CXL_DUMMY_READ_SIZE 128
#define CXL_DUMMY_READ_ALIGN 8
#define CXL_CAPI_WINDOW_START 0x2000000000000ull
#define CXL_CAPI_WINDOW_LOG_SIZE 48
#define CXL_XSL_CONFIG_CURRENT_VERSION CXL_XSL_CONFIG_VERSION1
bool cxllib_slot_is_supported(struct pci_dev *dev, unsigned long flags)
{
int rc;
u32 phb_index;
u64 chip_id, capp_unit_id;
/* No flags currently supported */
if (flags)
return false;
if (!cpu_has_feature(CPU_FTR_HVMODE))
return false;
if (!cxl_is_power9())
return false;
if (cxl_slot_is_switched(dev))
return false;
/* on p9, some pci slots are not connected to a CAPP unit */
rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id);
if (rc)
return false;
return true;
}
EXPORT_SYMBOL_GPL(cxllib_slot_is_supported);
static DEFINE_MUTEX(dra_mutex);
static u64 dummy_read_addr = CXL_INVALID_DRA;
static int allocate_dummy_read_buf(void)
{
u64 buf, vaddr;
size_t buf_size;
/*
* Dummy read buffer is 128-byte long, aligned on a
* 256-byte boundary and we need the physical address.
*/
buf_size = CXL_DUMMY_READ_SIZE + (1ull << CXL_DUMMY_READ_ALIGN);
buf = (u64) kzalloc(buf_size, GFP_KERNEL);
if (!buf)
return -ENOMEM;
vaddr = (buf + (1ull << CXL_DUMMY_READ_ALIGN) - 1) &
(~0ull << CXL_DUMMY_READ_ALIGN);
WARN((vaddr + CXL_DUMMY_READ_SIZE) > (buf + buf_size),
"Dummy read buffer alignment issue");
dummy_read_addr = virt_to_phys((void *) vaddr);
return 0;
}
int cxllib_get_xsl_config(struct pci_dev *dev, struct cxllib_xsl_config *cfg)
{
int rc;
u32 phb_index;
u64 chip_id, capp_unit_id;
if (!cpu_has_feature(CPU_FTR_HVMODE))
return -EINVAL;
mutex_lock(&dra_mutex);
if (dummy_read_addr == CXL_INVALID_DRA) {
rc = allocate_dummy_read_buf();
if (rc) {
mutex_unlock(&dra_mutex);
return rc;
}
}
mutex_unlock(&dra_mutex);
rc = cxl_calc_capp_routing(dev, &chip_id, &phb_index, &capp_unit_id);
if (rc)
return rc;
rc = cxl_get_xsl9_dsnctl(dev, capp_unit_id, &cfg->dsnctl);
if (rc)
return rc;
cfg->version = CXL_XSL_CONFIG_CURRENT_VERSION;
cfg->log_bar_size = CXL_CAPI_WINDOW_LOG_SIZE;
cfg->bar_addr = CXL_CAPI_WINDOW_START;
cfg->dra = dummy_read_addr;
return 0;
}
EXPORT_SYMBOL_GPL(cxllib_get_xsl_config);
int cxllib_switch_phb_mode(struct pci_dev *dev, enum cxllib_mode mode,
unsigned long flags)
{
int rc = 0;
if (!cpu_has_feature(CPU_FTR_HVMODE))
return -EINVAL;
switch (mode) {
case CXL_MODE_PCI:
/*
* We currently don't support going back to PCI mode
* However, we'll turn the invalidations off, so that
* the firmware doesn't have to ack them and can do
* things like reset, etc.. with no worries.
* So always return EPERM (can't go back to PCI) or
* EBUSY if we couldn't even turn off snooping
*/
rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_OFF);
if (rc)
rc = -EBUSY;
else
rc = -EPERM;
break;
case CXL_MODE_CXL:
/* DMA only supported on TVT1 for the time being */
if (flags != CXL_MODE_DMA_TVT1)
return -EINVAL;
rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_DMA_TVT1);
if (rc)
return rc;
rc = pnv_phb_to_cxl_mode(dev, OPAL_PHB_CAPI_MODE_SNOOP_ON);
break;
default:
rc = -EINVAL;
}
return rc;
}
EXPORT_SYMBOL_GPL(cxllib_switch_phb_mode);
/*
* When switching the PHB to capi mode, the TVT#1 entry for
* the Partitionable Endpoint is set in bypass mode, like
* in PCI mode.
* Configure the device dma to use TVT#1, which is done
* by calling dma_set_mask() with a mask large enough.
*/
int cxllib_set_device_dma(struct pci_dev *dev, unsigned long flags)
{
int rc;
if (flags)
return -EINVAL;
rc = dma_set_mask(&dev->dev, DMA_BIT_MASK(64));
return rc;
}
EXPORT_SYMBOL_GPL(cxllib_set_device_dma);
int cxllib_get_PE_attributes(struct task_struct *task,
unsigned long translation_mode,
struct cxllib_pe_attributes *attr)
{
if (translation_mode != CXL_TRANSLATED_MODE &&
translation_mode != CXL_REAL_MODE)
return -EINVAL;
attr->sr = cxl_calculate_sr(false,
task == NULL,
translation_mode == CXL_REAL_MODE,
true);
attr->lpid = mfspr(SPRN_LPID);
if (task) {
struct mm_struct *mm = get_task_mm(task);
if (mm == NULL)
return -EINVAL;
/*
* Caller is keeping a reference on mm_users for as long
* as XSL uses the memory context
*/
attr->pid = mm->context.id;
mmput(mm);
attr->tid = task->thread.tidr;
} else {
attr->pid = 0;
attr->tid = 0;
}
return 0;
}
EXPORT_SYMBOL_GPL(cxllib_get_PE_attributes);
static int get_vma_info(struct mm_struct *mm, u64 addr,
u64 *vma_start, u64 *vma_end,
unsigned long *page_size)
{
struct vm_area_struct *vma = NULL;
int rc = 0;
mmap_read_lock(mm);
vma = find_vma(mm, addr);
if (!vma) {
rc = -EFAULT;
goto out;
}
*page_size = vma_kernel_pagesize(vma);
*vma_start = vma->vm_start;
*vma_end = vma->vm_end;
out:
mmap_read_unlock(mm);
return rc;
}
int cxllib_handle_fault(struct mm_struct *mm, u64 addr, u64 size, u64 flags)
{
int rc;
u64 dar, vma_start, vma_end;
unsigned long page_size;
if (mm == NULL)
return -EFAULT;
/*
* The buffer we have to process can extend over several pages
* and may also cover several VMAs.
* We iterate over all the pages. The page size could vary
* between VMAs.
*/
rc = get_vma_info(mm, addr, &vma_start, &vma_end, &page_size);
if (rc)
return rc;
for (dar = (addr & ~(page_size - 1)); dar < (addr + size);
dar += page_size) {
if (dar < vma_start || dar >= vma_end) {
/*
* We don't hold mm->mmap_lock while iterating, since
* the lock is required by one of the lower-level page
* fault processing functions and it could
* create a deadlock.
*
* It means the VMAs can be altered between 2
* loop iterations and we could theoretically
* miss a page (however unlikely). But that's
* not really a problem, as the driver will
* retry access, get another page fault on the
* missing page and call us again.
*/
rc = get_vma_info(mm, dar, &vma_start, &vma_end,
&page_size);
if (rc)
return rc;
}
rc = cxl_handle_mm_fault(mm, flags, dar);
if (rc)
return -EFAULT;
}
return 0;
}
EXPORT_SYMBOL_GPL(cxllib_handle_fault);