// SPDX-License-Identifier: GPL-2.0
#define DEBUG
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <asm/spu.h>
#include <asm/spu_priv1.h>
#include <asm/io.h>
#include <asm/unistd.h>
#include "spufs.h"
/* interrupt-level stop callback function. */
void spufs_stop_callback(struct spu *spu, int irq)
{
struct spu_context *ctx = spu->ctx;
/*
* It should be impossible to preempt a context while an exception
* is being processed, since the context switch code is specially
* coded to deal with interrupts ... But, just in case, sanity check
* the context pointer. It is OK to return doing nothing since
* the exception will be regenerated when the context is resumed.
*/
if (ctx) {
/* Copy exception arguments into module specific structure */
switch(irq) {
case 0 :
ctx->csa.class_0_pending = spu->class_0_pending;
ctx->csa.class_0_dar = spu->class_0_dar;
break;
case 1 :
ctx->csa.class_1_dsisr = spu->class_1_dsisr;
ctx->csa.class_1_dar = spu->class_1_dar;
break;
case 2 :
break;
}
/* ensure that the exception status has hit memory before a
* thread waiting on the context's stop queue is woken */
smp_wmb();
wake_up_all(&ctx->stop_wq);
}
}
int spu_stopped(struct spu_context *ctx, u32 *stat)
{
u64 dsisr;
u32 stopped;
stopped = SPU_STATUS_INVALID_INSTR | SPU_STATUS_SINGLE_STEP |
SPU_STATUS_STOPPED_BY_HALT | SPU_STATUS_STOPPED_BY_STOP;
top:
*stat = ctx->ops->status_read(ctx);
if (*stat & stopped) {
/*
* If the spu hasn't finished stopping, we need to
* re-read the register to get the stopped value.
*/
if (*stat & SPU_STATUS_RUNNING)
goto top;
return 1;
}
if (test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
return 1;
dsisr = ctx->csa.class_1_dsisr;
if (dsisr & (MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED))
return 1;
if (ctx->csa.class_0_pending)
return 1;
return 0;
}
static int spu_setup_isolated(struct spu_context *ctx)
{
int ret;
u64 __iomem *mfc_cntl;
u64 sr1;
u32 status;
unsigned long timeout;
const u32 status_loading = SPU_STATUS_RUNNING
| SPU_STATUS_ISOLATED_STATE | SPU_STATUS_ISOLATED_LOAD_STATUS;
ret = -ENODEV;
if (!isolated_loader)
goto out;
/*
* We need to exclude userspace access to the context.
*
* To protect against memory access we invalidate all ptes
* and make sure the pagefault handlers block on the mutex.
*/
spu_unmap_mappings(ctx);
mfc_cntl = &ctx->spu->priv2->mfc_control_RW;
/* purge the MFC DMA queue to ensure no spurious accesses before we
* enter kernel mode */
timeout = jiffies + HZ;
out_be64(mfc_cntl, MFC_CNTL_PURGE_DMA_REQUEST);
while ((in_be64(mfc_cntl) & MFC_CNTL_PURGE_DMA_STATUS_MASK)
!= MFC_CNTL_PURGE_DMA_COMPLETE) {
if (time_after(jiffies, timeout)) {
printk(KERN_ERR "%s: timeout flushing MFC DMA queue\n",
__func__);
ret = -EIO;
goto out;
}
cond_resched();
}
/* clear purge status */
out_be64(mfc_cntl, 0);
/* put the SPE in kernel mode to allow access to the loader */
sr1 = spu_mfc_sr1_get(ctx->spu);
sr1 &= ~MFC_STATE1_PROBLEM_STATE_MASK;
spu_mfc_sr1_set(ctx->spu, sr1);
/* start the loader */
ctx->ops->signal1_write(ctx, (unsigned long)isolated_loader >> 32);
ctx->ops->signal2_write(ctx,
(unsigned long)isolated_loader & 0xffffffff);
ctx->ops->runcntl_write(ctx,
SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
ret = 0;
timeout = jiffies + HZ;
while (((status = ctx->ops->status_read(ctx)) & status_loading) ==
status_loading) {
if (time_after(jiffies, timeout)) {
printk(KERN_ERR "%s: timeout waiting for loader\n",
__func__);
ret = -EIO;
goto out_drop_priv;
}
cond_resched();
}
if (!(status & SPU_STATUS_RUNNING)) {
/* If isolated LOAD has failed: run SPU, we will get a stop-and
* signal later. */
pr_debug("%s: isolated LOAD failed\n", __func__);
ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
ret = -EACCES;
goto out_drop_priv;
}
if (!(status & SPU_STATUS_ISOLATED_STATE)) {
/* This isn't allowed by the CBEA, but check anyway */
pr_debug("%s: SPU fell out of isolated mode?\n", __func__);
ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_STOP);
ret = -EINVAL;
goto out_drop_priv;
}
out_drop_priv:
/* Finished accessing the loader. Drop kernel mode */
sr1 |= MFC_STATE1_PROBLEM_STATE_MASK;
spu_mfc_sr1_set(ctx->spu, sr1);
out:
return ret;
}
static int spu_run_init(struct spu_context *ctx, u32 *npc)
{
unsigned long runcntl = SPU_RUNCNTL_RUNNABLE;
int ret;
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
/*
* NOSCHED is synchronous scheduling with respect to the caller.
* The caller waits for the context to be loaded.
*/
if (ctx->flags & SPU_CREATE_NOSCHED) {
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
return ret;
}
}
/*
* Apply special setup as required.
*/
if (ctx->flags & SPU_CREATE_ISOLATE) {
if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
ret = spu_setup_isolated(ctx);
if (ret)
return ret;
}
/*
* If userspace has set the runcntrl register (eg, to
* issue an isolated exit), we need to re-set it here
*/
runcntl = ctx->ops->runcntl_read(ctx) &
(SPU_RUNCNTL_RUNNABLE | SPU_RUNCNTL_ISOLATE);
if (runcntl == 0)
runcntl = SPU_RUNCNTL_RUNNABLE;
} else {
unsigned long privcntl;
if (test_thread_flag(TIF_SINGLESTEP))
privcntl = SPU_PRIVCNTL_MODE_SINGLE_STEP;
else
privcntl = SPU_PRIVCNTL_MODE_NORMAL;
ctx->ops->privcntl_write(ctx, privcntl);
ctx->ops->npc_write(ctx, *npc);
}
ctx->ops->runcntl_write(ctx, runcntl);
if (ctx->flags & SPU_CREATE_NOSCHED) {
spuctx_switch_state(ctx, SPU_UTIL_USER);
} else {
if (ctx->state == SPU_STATE_SAVED) {
ret = spu_activate(ctx, 0);
if (ret)
return ret;
} else {
spuctx_switch_state(ctx, SPU_UTIL_USER);
}
}
set_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
return 0;
}
static int spu_run_fini(struct spu_context *ctx, u32 *npc,
u32 *status)
{
int ret = 0;
spu_del_from_rq(ctx);
*status = ctx->ops->status_read(ctx);
*npc = ctx->ops->npc_read(ctx);
spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
clear_bit(SPU_SCHED_SPU_RUN, &ctx->sched_flags);
spu_switch_log_notify(NULL, ctx, SWITCH_LOG_EXIT, *status);
spu_release(ctx);
if (signal_pending(current))
ret = -ERESTARTSYS;
return ret;
}
/*
* SPU syscall restarting is tricky because we violate the basic
* assumption that the signal handler is running on the interrupted
* thread. Here instead, the handler runs on PowerPC user space code,
* while the syscall was called from the SPU.
* This means we can only do a very rough approximation of POSIX
* signal semantics.
*/
static int spu_handle_restartsys(struct spu_context *ctx, long *spu_ret,
unsigned int *npc)
{
int ret;
switch (*spu_ret) {
case -ERESTARTSYS:
case -ERESTARTNOINTR:
/*
* Enter the regular syscall restarting for
* sys_spu_run, then restart the SPU syscall
* callback.
*/
*npc -= 8;
ret = -ERESTARTSYS;
break;
case -ERESTARTNOHAND:
case -ERESTART_RESTARTBLOCK:
/*
* Restart block is too hard for now, just return -EINTR
* to the SPU.
* ERESTARTNOHAND comes from sys_pause, we also return
* -EINTR from there.
* Assume that we need to be restarted ourselves though.
*/
*spu_ret = -EINTR;
ret = -ERESTARTSYS;
break;
default:
printk(KERN_WARNING "%s: unexpected return code %ld\n",
__func__, *spu_ret);
ret = 0;
}
return ret;
}
static int spu_process_callback(struct spu_context *ctx)
{
struct spu_syscall_block s;
u32 ls_pointer, npc;
void __iomem *ls;
long spu_ret;
int ret;
/* get syscall block from local store */
npc = ctx->ops->npc_read(ctx) & ~3;
ls = (void __iomem *)ctx->ops->get_ls(ctx);
ls_pointer = in_be32(ls + npc);
if (ls_pointer > (LS_SIZE - sizeof(s)))
return -EFAULT;
memcpy_fromio(&s, ls + ls_pointer, sizeof(s));
/* do actual syscall without pinning the spu */
ret = 0;
spu_ret = -ENOSYS;
npc += 4;
if (s.nr_ret < NR_syscalls) {
spu_release(ctx);
/* do actual system call from here */
spu_ret = spu_sys_callback(&s);
if (spu_ret <= -ERESTARTSYS) {
ret = spu_handle_restartsys(ctx, &spu_ret, &npc);
}
mutex_lock(&ctx->state_mutex);
if (ret == -ERESTARTSYS)
return ret;
}
/* need to re-get the ls, as it may have changed when we released the
* spu */
ls = (void __iomem *)ctx->ops->get_ls(ctx);
/* write result, jump over indirect pointer */
memcpy_toio(ls + ls_pointer, &spu_ret, sizeof(spu_ret));
ctx->ops->npc_write(ctx, npc);
ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
return ret;
}
long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *event)
{
int ret;
struct spu *spu;
u32 status;
if (mutex_lock_interruptible(&ctx->run_mutex))
return -ERESTARTSYS;
ctx->event_return = 0;
ret = spu_acquire(ctx);
if (ret)
goto out_unlock;
spu_enable_spu(ctx);
spu_update_sched_info(ctx);
ret = spu_run_init(ctx, npc);
if (ret) {
spu_release(ctx);
goto out;
}
do {
ret = spufs_wait(ctx->stop_wq, spu_stopped(ctx, &status));
if (unlikely(ret)) {
/*
* This is nasty: we need the state_mutex for all the
* bookkeeping even if the syscall was interrupted by
* a signal. ewww.
*/
mutex_lock(&ctx->state_mutex);
break;
}
spu = ctx->spu;
if (unlikely(test_and_clear_bit(SPU_SCHED_NOTIFY_ACTIVE,
&ctx->sched_flags))) {
if (!(status & SPU_STATUS_STOPPED_BY_STOP)) {
spu_switch_notify(spu, ctx);
continue;
}
}
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
(status >> SPU_STOP_STATUS_SHIFT == 0x2104)) {
ret = spu_process_callback(ctx);
if (ret)
break;
status &= ~SPU_STATUS_STOPPED_BY_STOP;
}
ret = spufs_handle_class1(ctx);
if (ret)
break;
ret = spufs_handle_class0(ctx);
if (ret)
break;
if (signal_pending(current))
ret = -ERESTARTSYS;
} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
SPU_STATUS_STOPPED_BY_HALT |
SPU_STATUS_SINGLE_STEP)));
spu_disable_spu(ctx);
ret = spu_run_fini(ctx, npc, &status);
spu_yield(ctx);
if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
(((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
ctx->stats.libassist++;
if ((ret == 0) ||
((ret == -ERESTARTSYS) &&
((status & SPU_STATUS_STOPPED_BY_HALT) ||
(status & SPU_STATUS_SINGLE_STEP) ||
((status & SPU_STATUS_STOPPED_BY_STOP) &&
(status >> SPU_STOP_STATUS_SHIFT != 0x2104)))))
ret = status;
/* Note: we don't need to force_sig SIGTRAP on single-step
* since we have TIF_SINGLESTEP set, thus the kernel will do
* it upon return from the syscall anyway.
*/
if (unlikely(status & SPU_STATUS_SINGLE_STEP))
ret = -ERESTARTSYS;
else if (unlikely((status & SPU_STATUS_STOPPED_BY_STOP)
&& (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff)) {
force_sig(SIGTRAP, current);
ret = -ERESTARTSYS;
}
out:
*event = ctx->event_return;
out_unlock:
mutex_unlock(&ctx->run_mutex);
return ret;
}
