382 lines
9.1 KiB
C
382 lines
9.1 KiB
C
/*
|
|
* 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/workqueue.h>
|
|
#include <linux/sched/signal.h>
|
|
#include <linux/sched/mm.h>
|
|
#include <linux/pid.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/moduleparam.h>
|
|
|
|
#undef MODULE_PARAM_PREFIX
|
|
#define MODULE_PARAM_PREFIX "cxl" "."
|
|
#include <asm/current.h>
|
|
#include <asm/copro.h>
|
|
#include <asm/mmu.h>
|
|
|
|
#include "cxl.h"
|
|
#include "trace.h"
|
|
|
|
static bool sste_matches(struct cxl_sste *sste, struct copro_slb *slb)
|
|
{
|
|
return ((sste->vsid_data == cpu_to_be64(slb->vsid)) &&
|
|
(sste->esid_data == cpu_to_be64(slb->esid)));
|
|
}
|
|
|
|
/*
|
|
* This finds a free SSTE for the given SLB, or returns NULL if it's already in
|
|
* the segment table.
|
|
*/
|
|
static struct cxl_sste* find_free_sste(struct cxl_context *ctx,
|
|
struct copro_slb *slb)
|
|
{
|
|
struct cxl_sste *primary, *sste, *ret = NULL;
|
|
unsigned int mask = (ctx->sst_size >> 7) - 1; /* SSTP0[SegTableSize] */
|
|
unsigned int entry;
|
|
unsigned int hash;
|
|
|
|
if (slb->vsid & SLB_VSID_B_1T)
|
|
hash = (slb->esid >> SID_SHIFT_1T) & mask;
|
|
else /* 256M */
|
|
hash = (slb->esid >> SID_SHIFT) & mask;
|
|
|
|
primary = ctx->sstp + (hash << 3);
|
|
|
|
for (entry = 0, sste = primary; entry < 8; entry++, sste++) {
|
|
if (!ret && !(be64_to_cpu(sste->esid_data) & SLB_ESID_V))
|
|
ret = sste;
|
|
if (sste_matches(sste, slb))
|
|
return NULL;
|
|
}
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* Nothing free, select an entry to cast out */
|
|
ret = primary + ctx->sst_lru;
|
|
ctx->sst_lru = (ctx->sst_lru + 1) & 0x7;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void cxl_load_segment(struct cxl_context *ctx, struct copro_slb *slb)
|
|
{
|
|
/* mask is the group index, we search primary and secondary here. */
|
|
struct cxl_sste *sste;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->sste_lock, flags);
|
|
sste = find_free_sste(ctx, slb);
|
|
if (!sste)
|
|
goto out_unlock;
|
|
|
|
pr_devel("CXL Populating SST[%li]: %#llx %#llx\n",
|
|
sste - ctx->sstp, slb->vsid, slb->esid);
|
|
trace_cxl_ste_write(ctx, sste - ctx->sstp, slb->esid, slb->vsid);
|
|
|
|
sste->vsid_data = cpu_to_be64(slb->vsid);
|
|
sste->esid_data = cpu_to_be64(slb->esid);
|
|
out_unlock:
|
|
spin_unlock_irqrestore(&ctx->sste_lock, flags);
|
|
}
|
|
|
|
static int cxl_fault_segment(struct cxl_context *ctx, struct mm_struct *mm,
|
|
u64 ea)
|
|
{
|
|
struct copro_slb slb = {0,0};
|
|
int rc;
|
|
|
|
if (!(rc = copro_calculate_slb(mm, ea, &slb))) {
|
|
cxl_load_segment(ctx, &slb);
|
|
}
|
|
|
|
return rc;
|
|
}
|
|
|
|
static void cxl_ack_ae(struct cxl_context *ctx)
|
|
{
|
|
unsigned long flags;
|
|
|
|
cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_AE, 0);
|
|
|
|
spin_lock_irqsave(&ctx->lock, flags);
|
|
ctx->pending_fault = true;
|
|
ctx->fault_addr = ctx->dar;
|
|
ctx->fault_dsisr = ctx->dsisr;
|
|
spin_unlock_irqrestore(&ctx->lock, flags);
|
|
|
|
wake_up_all(&ctx->wq);
|
|
}
|
|
|
|
static int cxl_handle_segment_miss(struct cxl_context *ctx,
|
|
struct mm_struct *mm, u64 ea)
|
|
{
|
|
int rc;
|
|
|
|
pr_devel("CXL interrupt: Segment fault pe: %i ea: %#llx\n", ctx->pe, ea);
|
|
trace_cxl_ste_miss(ctx, ea);
|
|
|
|
if ((rc = cxl_fault_segment(ctx, mm, ea)))
|
|
cxl_ack_ae(ctx);
|
|
else {
|
|
|
|
mb(); /* Order seg table write to TFC MMIO write */
|
|
cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
|
|
}
|
|
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
static void cxl_handle_page_fault(struct cxl_context *ctx,
|
|
struct mm_struct *mm, u64 dsisr, u64 dar)
|
|
{
|
|
unsigned flt = 0;
|
|
int result;
|
|
unsigned long access, flags, inv_flags = 0;
|
|
|
|
trace_cxl_pte_miss(ctx, dsisr, dar);
|
|
|
|
if ((result = copro_handle_mm_fault(mm, dar, dsisr, &flt))) {
|
|
pr_devel("copro_handle_mm_fault failed: %#x\n", result);
|
|
return cxl_ack_ae(ctx);
|
|
}
|
|
|
|
/*
|
|
* update_mmu_cache() will not have loaded the hash since current->trap
|
|
* is not a 0x400 or 0x300, so just call hash_page_mm() here.
|
|
*/
|
|
access = _PAGE_PRESENT | _PAGE_READ;
|
|
if (dsisr & CXL_PSL_DSISR_An_S)
|
|
access |= _PAGE_WRITE;
|
|
|
|
access |= _PAGE_PRIVILEGED;
|
|
if ((!ctx->kernel) || (REGION_ID(dar) == USER_REGION_ID))
|
|
access &= ~_PAGE_PRIVILEGED;
|
|
|
|
if (dsisr & DSISR_NOHPTE)
|
|
inv_flags |= HPTE_NOHPTE_UPDATE;
|
|
|
|
local_irq_save(flags);
|
|
hash_page_mm(mm, dar, access, 0x300, inv_flags);
|
|
local_irq_restore(flags);
|
|
|
|
pr_devel("Page fault successfully handled for pe: %i!\n", ctx->pe);
|
|
cxl_ops->ack_irq(ctx, CXL_PSL_TFC_An_R, 0);
|
|
}
|
|
|
|
/*
|
|
* Returns the mm_struct corresponding to the context ctx via ctx->pid
|
|
* In case the task has exited we use the task group leader accessible
|
|
* via ctx->glpid to find the next task in the thread group that has a
|
|
* valid mm_struct associated with it. If a task with valid mm_struct
|
|
* is found the ctx->pid is updated to use the task struct for subsequent
|
|
* translations. In case no valid mm_struct is found in the task group to
|
|
* service the fault a NULL is returned.
|
|
*/
|
|
static struct mm_struct *get_mem_context(struct cxl_context *ctx)
|
|
{
|
|
struct task_struct *task = NULL;
|
|
struct mm_struct *mm = NULL;
|
|
struct pid *old_pid = ctx->pid;
|
|
|
|
if (old_pid == NULL) {
|
|
pr_warn("%s: Invalid context for pe=%d\n",
|
|
__func__, ctx->pe);
|
|
return NULL;
|
|
}
|
|
|
|
task = get_pid_task(old_pid, PIDTYPE_PID);
|
|
|
|
/*
|
|
* pid_alive may look racy but this saves us from costly
|
|
* get_task_mm when the task is a zombie. In worst case
|
|
* we may think a task is alive, which is about to die
|
|
* but get_task_mm will return NULL.
|
|
*/
|
|
if (task != NULL && pid_alive(task))
|
|
mm = get_task_mm(task);
|
|
|
|
/* release the task struct that was taken earlier */
|
|
if (task)
|
|
put_task_struct(task);
|
|
else
|
|
pr_devel("%s: Context owning pid=%i for pe=%i dead\n",
|
|
__func__, pid_nr(old_pid), ctx->pe);
|
|
|
|
/*
|
|
* If we couldn't find the mm context then use the group
|
|
* leader to iterate over the task group and find a task
|
|
* that gives us mm_struct.
|
|
*/
|
|
if (unlikely(mm == NULL && ctx->glpid != NULL)) {
|
|
|
|
rcu_read_lock();
|
|
task = pid_task(ctx->glpid, PIDTYPE_PID);
|
|
if (task)
|
|
do {
|
|
mm = get_task_mm(task);
|
|
if (mm) {
|
|
ctx->pid = get_task_pid(task,
|
|
PIDTYPE_PID);
|
|
break;
|
|
}
|
|
task = next_thread(task);
|
|
} while (task && !thread_group_leader(task));
|
|
rcu_read_unlock();
|
|
|
|
/* check if we switched pid */
|
|
if (ctx->pid != old_pid) {
|
|
if (mm)
|
|
pr_devel("%s:pe=%i switch pid %i->%i\n",
|
|
__func__, ctx->pe, pid_nr(old_pid),
|
|
pid_nr(ctx->pid));
|
|
else
|
|
pr_devel("%s:Cannot find mm for pid=%i\n",
|
|
__func__, pid_nr(old_pid));
|
|
|
|
/* drop the reference to older pid */
|
|
put_pid(old_pid);
|
|
}
|
|
}
|
|
|
|
return mm;
|
|
}
|
|
|
|
|
|
|
|
void cxl_handle_fault(struct work_struct *fault_work)
|
|
{
|
|
struct cxl_context *ctx =
|
|
container_of(fault_work, struct cxl_context, fault_work);
|
|
u64 dsisr = ctx->dsisr;
|
|
u64 dar = ctx->dar;
|
|
struct mm_struct *mm = NULL;
|
|
|
|
if (cpu_has_feature(CPU_FTR_HVMODE)) {
|
|
if (cxl_p2n_read(ctx->afu, CXL_PSL_DSISR_An) != dsisr ||
|
|
cxl_p2n_read(ctx->afu, CXL_PSL_DAR_An) != dar ||
|
|
cxl_p2n_read(ctx->afu, CXL_PSL_PEHandle_An) != ctx->pe) {
|
|
/* Most likely explanation is harmless - a dedicated
|
|
* process has detached and these were cleared by the
|
|
* PSL purge, but warn about it just in case
|
|
*/
|
|
dev_notice(&ctx->afu->dev, "cxl_handle_fault: Translation fault regs changed\n");
|
|
return;
|
|
}
|
|
}
|
|
|
|
/* Early return if the context is being / has been detached */
|
|
if (ctx->status == CLOSED) {
|
|
cxl_ack_ae(ctx);
|
|
return;
|
|
}
|
|
|
|
pr_devel("CXL BOTTOM HALF handling fault for afu pe: %i. "
|
|
"DSISR: %#llx DAR: %#llx\n", ctx->pe, dsisr, dar);
|
|
|
|
if (!ctx->kernel) {
|
|
|
|
mm = get_mem_context(ctx);
|
|
/* indicates all the thread in task group have exited */
|
|
if (mm == NULL) {
|
|
pr_devel("%s: unable to get mm for pe=%d pid=%i\n",
|
|
__func__, ctx->pe, pid_nr(ctx->pid));
|
|
cxl_ack_ae(ctx);
|
|
return;
|
|
} else {
|
|
pr_devel("Handling page fault for pe=%d pid=%i\n",
|
|
ctx->pe, pid_nr(ctx->pid));
|
|
}
|
|
}
|
|
|
|
if (dsisr & CXL_PSL_DSISR_An_DS)
|
|
cxl_handle_segment_miss(ctx, mm, dar);
|
|
else if (dsisr & CXL_PSL_DSISR_An_DM)
|
|
cxl_handle_page_fault(ctx, mm, dsisr, dar);
|
|
else
|
|
WARN(1, "cxl_handle_fault has nothing to handle\n");
|
|
|
|
if (mm)
|
|
mmput(mm);
|
|
}
|
|
|
|
static void cxl_prefault_one(struct cxl_context *ctx, u64 ea)
|
|
{
|
|
struct mm_struct *mm;
|
|
|
|
mm = get_mem_context(ctx);
|
|
if (mm == NULL) {
|
|
pr_devel("cxl_prefault_one unable to get mm %i\n",
|
|
pid_nr(ctx->pid));
|
|
return;
|
|
}
|
|
|
|
cxl_fault_segment(ctx, mm, ea);
|
|
|
|
mmput(mm);
|
|
}
|
|
|
|
static u64 next_segment(u64 ea, u64 vsid)
|
|
{
|
|
if (vsid & SLB_VSID_B_1T)
|
|
ea |= (1ULL << 40) - 1;
|
|
else
|
|
ea |= (1ULL << 28) - 1;
|
|
|
|
return ea + 1;
|
|
}
|
|
|
|
static void cxl_prefault_vma(struct cxl_context *ctx)
|
|
{
|
|
u64 ea, last_esid = 0;
|
|
struct copro_slb slb;
|
|
struct vm_area_struct *vma;
|
|
int rc;
|
|
struct mm_struct *mm;
|
|
|
|
mm = get_mem_context(ctx);
|
|
if (mm == NULL) {
|
|
pr_devel("cxl_prefault_vm unable to get mm %i\n",
|
|
pid_nr(ctx->pid));
|
|
return;
|
|
}
|
|
|
|
down_read(&mm->mmap_sem);
|
|
for (vma = mm->mmap; vma; vma = vma->vm_next) {
|
|
for (ea = vma->vm_start; ea < vma->vm_end;
|
|
ea = next_segment(ea, slb.vsid)) {
|
|
rc = copro_calculate_slb(mm, ea, &slb);
|
|
if (rc)
|
|
continue;
|
|
|
|
if (last_esid == slb.esid)
|
|
continue;
|
|
|
|
cxl_load_segment(ctx, &slb);
|
|
last_esid = slb.esid;
|
|
}
|
|
}
|
|
up_read(&mm->mmap_sem);
|
|
|
|
mmput(mm);
|
|
}
|
|
|
|
void cxl_prefault(struct cxl_context *ctx, u64 wed)
|
|
{
|
|
switch (ctx->afu->prefault_mode) {
|
|
case CXL_PREFAULT_WED:
|
|
cxl_prefault_one(ctx, wed);
|
|
break;
|
|
case CXL_PREFAULT_ALL:
|
|
cxl_prefault_vma(ctx);
|
|
break;
|
|
default:
|
|
break;
|
|
}
|
|
}
|