ppc: Get out of emulation on SMT "OR" ops
Otherwise tight loops at smt_low for example, which OPAL does, eat so much CPU that we can't boot a kernel anymore. With that, I can boot 8 CPUs just fine with powernv. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
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@ -1392,6 +1392,19 @@ GEN_LOGICAL2(nand, tcg_gen_nand_tl, 0x0E, PPC_INTEGER);
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/* nor & nor. */
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GEN_LOGICAL2(nor, tcg_gen_nor_tl, 0x03, PPC_INTEGER);
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#if defined(TARGET_PPC64)
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static void gen_pause(DisasContext *ctx)
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{
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TCGv_i32 t0 = tcg_const_i32(0);
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tcg_gen_st_i32(t0, cpu_env,
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-offsetof(PowerPCCPU, env) + offsetof(CPUState, halted));
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tcg_temp_free_i32(t0);
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/* Stop translation, this gives other CPUs a chance to run */
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gen_exception_err(ctx, EXCP_HLT, 1);
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}
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#endif /* defined(TARGET_PPC64) */
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/* or & or. */
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static void gen_or(DisasContext *ctx)
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{
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@ -1447,7 +1460,7 @@ static void gen_or(DisasContext *ctx)
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}
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break;
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case 7:
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if (ctx->hv) {
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if (ctx->hv && !ctx->pr) {
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/* Set process priority to very high */
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prio = 7;
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}
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@ -1464,6 +1477,10 @@ static void gen_or(DisasContext *ctx)
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tcg_gen_ori_tl(t0, t0, ((uint64_t)prio) << 50);
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gen_store_spr(SPR_PPR, t0);
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tcg_temp_free(t0);
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/* Pause us out of TCG otherwise spin loops with smt_low
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* eat too much CPU and the kernel hangs
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*/
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gen_pause(ctx);
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}
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#endif
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}
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@ -1489,8 +1506,6 @@ static void gen_ori(DisasContext *ctx)
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target_ulong uimm = UIMM(ctx->opcode);
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if (rS(ctx->opcode) == rA(ctx->opcode) && uimm == 0) {
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/* NOP */
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/* XXX: should handle special NOPs for POWER series */
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return;
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}
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tcg_gen_ori_tl(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)], uimm);
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