[POWERPC] spufs: Fix update of mailbox status register during backed wbox write

When a process writes into the inbound spu mailbox (wbox) while the
context is saved, we accidentally break the contents of the mb_stat_R
register by clearing other entries of the mailbox status register. This
can cause the user side to hang.

This change fixes the problem by only altering the appropriate bits
of the mailbox status register during a backing-store write.

Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Arnd Bergmann 2007-08-21 10:06:22 +08:00 committed by Paul Mackerras
parent aac2e68481
commit 62ee68e3bc

View file

@ -162,7 +162,8 @@ static int spu_backing_wbox_write(struct spu_context *ctx, u32 data)
BUG_ON(avail != (4 - slot));
ctx->csa.spu_mailbox_data[slot] = data;
ctx->csa.spu_chnlcnt_RW[29] = ++slot;
ctx->csa.prob.mb_stat_R = (((4 - slot) & 0xff) << 8);
ctx->csa.prob.mb_stat_R &= ~(0x00ff00);
ctx->csa.prob.mb_stat_R |= (((4 - slot) & 0xff) << 8);
gen_spu_event(ctx, MFC_SPU_MAILBOX_WRITTEN_EVENT);
ret = 4;
} else {