aboutsummaryrefslogtreecommitdiff
path: root/target-ppc
diff options
context:
space:
mode:
authorAaron Larson <alarson@ddci.com>2016-06-24 13:18:28 -0700
committerDavid Gibson <david@gibson.dropbear.id.au>2016-07-01 13:41:47 +1000
commit9e196938aa1c0517f81139bda0f2f26e0347c64e (patch)
tree66263f23a196ab14f91d7ecb1c3d23b3633483d6 /target-ppc
parent27f2458245e259618beb2635abccf00286ea8b2d (diff)
target-ppc: gen_pause for instructions: yield, mdoio, mdoom, miso
Call gen_pause for all "or rx,rx,rx" encodings other nop. This provides a reasonable implementation for yield, and a better approximation for mdoio, mdoom, and miso. The choice to pause for all encodings !=0 leverages the PowerISA admonition that the reserved encodings might change program priority, providing a slight "future proofing". Signed-off-by: Aaron Larson <alarson@ddci.com> Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Diffstat (limited to 'target-ppc')
-rw-r--r--target-ppc/translate.c15
1 files changed, 8 insertions, 7 deletions
diff --git a/target-ppc/translate.c b/target-ppc/translate.c
index 49fe761407..92030b66a5 100644
--- a/target-ppc/translate.c
+++ b/target-ppc/translate.c
@@ -1471,7 +1471,7 @@ static void gen_or(DisasContext *ctx)
} else if (unlikely(Rc(ctx->opcode) != 0)) {
gen_set_Rc0(ctx, cpu_gpr[rs]);
#if defined(TARGET_PPC64)
- } else {
+ } else if (rs != 0) { /* 0 is nop */
int prio = 0;
switch (rs) {
@@ -1514,7 +1514,6 @@ static void gen_or(DisasContext *ctx)
break;
#endif
default:
- /* nop */
break;
}
if (prio) {
@@ -1524,13 +1523,15 @@ static void gen_or(DisasContext *ctx)
tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50);
gen_store_spr(SPR_PPR, t0);
tcg_temp_free(t0);
- /* Pause us out of TCG otherwise spin loops with smt_low
- * eat too much CPU and the kernel hangs
- */
+ }
#if !defined(CONFIG_USER_ONLY)
- gen_pause(ctx);
+ /* Pause out of TCG otherwise spin loops with smt_low eat too much
+ * CPU and the kernel hangs. This applies to all encodings other
+ * than no-op, e.g., miso(rs=26), yield(27), mdoio(29), mdoom(30),
+ * and all currently undefined.
+ */
+ gen_pause(ctx);
#endif
- }
#endif
}
}