diff options
| author | Aaron Larson <alarson@ddci.com> | 2016-06-24 13:18:28 -0700 |
|---|---|---|
| committer | David Gibson <david@gibson.dropbear.id.au> | 2016-07-01 13:41:47 +1000 |
| commit | 9e196938aa1c0517f81139bda0f2f26e0347c64e (patch) | |
| tree | 66263f23a196ab14f91d7ecb1c3d23b3633483d6 | |
| parent | 27f2458245e259618beb2635abccf00286ea8b2d (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>
| -rw-r--r-- | target-ppc/translate.c | 15 |
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 } } |