[POWERPC] spufs: Add support for SPU single stepping
This patch adds support for SPU single stepping. The single
step bit is set in the SPU when the current process is
being single-stepped via ptrace. The spu then stops and
returns with a specific flag set and the syscall exit code
will generate the SIGTRAP.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
diff --git a/arch/powerpc/platforms/cell/spufs/run.c b/arch/powerpc/platforms/cell/spufs/run.c
index 5762660..6625ed2 100644
--- a/arch/powerpc/platforms/cell/spufs/run.c
+++ b/arch/powerpc/platforms/cell/spufs/run.c
@@ -142,8 +142,12 @@
runcntl = SPU_RUNCNTL_RUNNABLE;
ctx->ops->runcntl_write(ctx, runcntl);
} else {
+ unsigned long mode = SPU_PRIVCNTL_MODE_NORMAL;
spu_start_tick(ctx);
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);
}
@@ -334,7 +338,8 @@
ret = spu_process_events(ctx);
} while (!ret && !(status & (SPU_STATUS_STOPPED_BY_STOP |
- SPU_STATUS_STOPPED_BY_HALT)));
+ SPU_STATUS_STOPPED_BY_HALT |
+ SPU_STATUS_SINGLE_STEP)));
ctx->ops->master_stop(ctx);
ret = spu_run_fini(ctx, npc, &status);
@@ -344,10 +349,15 @@
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);