linux/arch/powerpc/platforms/cell/spufs/run.c

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#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)
{
struct spu_context *ctx = spu->ctx;
wake_up_all(&ctx->stop_wq);
}
static inline int spu_stopped(struct spu_context *ctx, u32 *stat)
{
struct spu *spu;
u64 pte_fault;
*stat = ctx->ops->status_read(ctx);
spu = ctx->spu;
if (ctx->state != SPU_STATE_RUNNABLE ||
test_bit(SPU_SCHED_NOTIFY_ACTIVE, &ctx->sched_flags))
return 1;
pte_fault = spu->dsisr &
(MFC_DSISR_PTE_NOT_FOUND | MFC_DSISR_ACCESS_DENIED);
return (!(*stat & SPU_STATUS_RUNNING) || pte_fault || spu->class_0_pending) ?
1 : 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",
__FUNCTION__);
ret = -EIO;
goto out;
}
cond_resched();
}
/* 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",
__FUNCTION__);
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", __FUNCTION__);
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", __FUNCTION__);
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)
{
spuctx_switch_state(ctx, SPU_UTIL_SYSTEM);
if (ctx->flags & SPU_CREATE_ISOLATE) {
unsigned long runcntl;
if (!(ctx->ops->status_read(ctx) & SPU_STATUS_ISOLATED_STATE)) {
int 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;
ctx->ops->runcntl_write(ctx, runcntl);
} else {
unsigned long mode = SPU_PRIVCNTL_MODE_NORMAL;
ctx->ops->npc_write(ctx, *npc);
if (test_thread_flag(TIF_SINGLESTEP))
mode = SPU_PRIVCNTL_MODE_SINGLE_STEP;
out_be64(&ctx->spu->priv2->spu_privcntl_RW, mode);
ctx->ops->runcntl_write(ctx, SPU_RUNCNTL_RUNNABLE);
}
spuctx_switch_state(ctx, SPU_UTIL_USER);
return 0;
}
static int spu_run_fini(struct spu_context *ctx, u32 *npc,
u32 *status)
{
int ret = 0;
*status = ctx->ops->status_read(ctx);
*npc = ctx->ops->npc_read(ctx);
spuctx_switch_state(ctx, SPU_UTIL_IDLE_LOADED);
spu_release(ctx);
if (signal_pending(current))
ret = -ERESTARTSYS;
return ret;
}
static int spu_reacquire_runnable(struct spu_context *ctx, u32 *npc,
u32 *status)
{
int ret;
ret = spu_run_fini(ctx, npc, status);
if (ret)
return ret;
if (*status & (SPU_STATUS_STOPPED_BY_STOP | SPU_STATUS_STOPPED_BY_HALT))
return *status;
ret = spu_acquire_runnable(ctx, 0);
if (ret)
return ret;
spuctx_switch_state(ctx, SPU_UTIL_USER);
return 0;
}
/*
* 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",
__FUNCTION__, *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);
}
spu_acquire(ctx);
if (ret == -ERESTARTSYS)
return ret;
}
/* 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;
}
static inline int spu_process_events(struct spu_context *ctx)
{
struct spu *spu = ctx->spu;
int ret = 0;
if (spu->class_0_pending)
ret = spu_irq_class_0_bottom(spu);
if (!ret && signal_pending(current))
ret = -ERESTARTSYS;
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->ops->master_start(ctx);
ctx->event_return = 0;
spu_acquire(ctx);
if (ctx->state == SPU_STATE_SAVED) {
__spu_update_sched_info(ctx);
spu_set_timeslice(ctx);
ret = spu_activate(ctx, 0);
if (ret) {
spu_release(ctx);
goto out;
}
} else {
/*
* We have to update the scheduling priority under active_mutex
* to protect against find_victim().
*
* No need to update the timeslice ASAP, it will get updated
* once the current one has expired.
*/
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))
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;
if (unlikely(ctx->state != SPU_STATE_RUNNABLE)) {
ret = spu_reacquire_runnable(ctx, npc, &status);
if (ret)
goto out2;
continue;
}
ret = spu_process_events(ctx);
} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
SPU_STATUS_STOPPED_BY_HALT |
SPU_STATUS_SINGLE_STEP)));
if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
(((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100) &&
(ctx->state == SPU_STATE_RUNNABLE))
ctx->stats.libassist++;
ctx->ops->master_stop(ctx);
ret = spu_run_fini(ctx, npc, &status);
spu_yield(ctx);
out2:
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 anyawy
*/
if ((status & SPU_STATUS_STOPPED_BY_STOP)
&& (status >> SPU_STOP_STATUS_SHIFT) == 0x3fff) {
force_sig(SIGTRAP, current);
ret = -ERESTARTSYS;
}
out:
*event = ctx->event_return;
mutex_unlock(&ctx->run_mutex);
return ret;
}