[PATCH] spufs: switchable spu contexts
Add some infrastructure for saving and restoring the context of an
SPE. This patch creates a new structure that can hold the whole
state of a physical SPE in memory. It also contains code that
avoids races during the context switch and the binary code that
is loaded to the SPU in order to access its registers.
The actual PPE- and SPE-side context switch code are two separate
patches.
Signed-off-by: Arnd Bergmann <arndb@de.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/cell/spu_base.c b/arch/powerpc/platforms/cell/spu_base.c
index 9e90965..44492d8 100644
--- a/arch/powerpc/platforms/cell/spu_base.c
+++ b/arch/powerpc/platforms/cell/spu_base.c
@@ -62,7 +62,9 @@
static void spu_restart_dma(struct spu *spu)
{
struct spu_priv2 __iomem *priv2 = spu->priv2;
- out_be64(&priv2->mfc_control_RW, MFC_CNTL_RESTART_DMA_COMMAND);
+
+ if (!test_bit(SPU_CONTEXT_SWITCH_PENDING_nr, &spu->flags))
+ out_be64(&priv2->mfc_control_RW, MFC_CNTL_RESTART_DMA_COMMAND);
}
static int __spu_trap_data_seg(struct spu *spu, unsigned long ea)
@@ -72,6 +74,11 @@
pr_debug("%s\n", __FUNCTION__);
+ if (test_bit(SPU_CONTEXT_SWITCH_ACTIVE_nr, &spu->flags)) {
+ printk("%s: invalid access during switch!\n", __func__);
+ return 1;
+ }
+
if (REGION_ID(ea) != USER_REGION_ID) {
pr_debug("invalid region access at %016lx\n", ea);
return 1;
@@ -98,6 +105,7 @@
return 0;
}
+extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap); //XXX
static int __spu_trap_data_map(struct spu *spu, unsigned long ea)
{
unsigned long dsisr;
@@ -107,8 +115,21 @@
priv1 = spu->priv1;
dsisr = in_be64(&priv1->mfc_dsisr_RW);
- wake_up(&spu->stop_wq);
+ /* Handle kernel space hash faults immediately.
+ User hash faults need to be deferred to process context. */
+ if ((dsisr & MFC_DSISR_PTE_NOT_FOUND)
+ && REGION_ID(ea) != USER_REGION_ID
+ && hash_page(ea, _PAGE_PRESENT, 0x300) == 0) {
+ spu_restart_dma(spu);
+ return 0;
+ }
+ if (test_bit(SPU_CONTEXT_SWITCH_ACTIVE_nr, &spu->flags)) {
+ printk("%s: invalid access during switch!\n", __func__);
+ return 1;
+ }
+
+ wake_up(&spu->stop_wq);
return 0;
}
@@ -382,7 +403,6 @@
}
EXPORT_SYMBOL(spu_free);
-extern int hash_page(unsigned long ea, unsigned long access, unsigned long trap); //XXX
static int spu_handle_mm_fault(struct spu *spu)
{
struct spu_priv1 __iomem *priv1;
@@ -650,6 +670,7 @@
spu->slb_replace = 0;
spu->mm = NULL;
spu->class_0_pending = 0;
+ spu->flags = 0UL;
spin_lock_init(&spu->register_lock);
out_be64(&spu->priv1->mfc_sdr_RW, mfspr(SPRN_SDR1));