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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>
This commit is contained in:
Benjamin Herrenschmidt 2016-05-03 18:03:33 +02:00 committed by David Gibson
parent c409bc5daf
commit b68e60e6f0
1 changed files with 18 additions and 3 deletions
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21
target-ppc/translate.c
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@ -1392,6 +1392,19 @@ GEN_LOGICAL2(nand, tcg_gen_nand_tl, 0x0E, PPC_INTEGER);
/* nor & nor. */
GEN_LOGICAL2(nor, tcg_gen_nor_tl, 0x03, PPC_INTEGER);
#if defined(TARGET_PPC64)
static void gen_pause(DisasContext *ctx)
{
TCGv_i32 t0 = tcg_const_i32(0);
tcg_gen_st_i32(t0, cpu_env,
-offsetof(PowerPCCPU, env) + offsetof(CPUState, halted));
tcg_temp_free_i32(t0);
/* Stop translation, this gives other CPUs a chance to run */
gen_exception_err(ctx, EXCP_HLT, 1);
}
#endif /* defined(TARGET_PPC64) */
/* or & or. */
static void gen_or(DisasContext *ctx)
{
@ -1447,7 +1460,7 @@ static void gen_or(DisasContext *ctx)
}
break;
case 7:
if (ctx->hv) {
if (ctx->hv && !ctx->pr) {
/* Set process priority to very high */
prio = 7;
}
@ -1464,6 +1477,10 @@ 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
*/
gen_pause(ctx);
}
#endif
}
@ -1489,8 +1506,6 @@ static void gen_ori(DisasContext *ctx)
target_ulong uimm = UIMM(ctx->opcode);
if (rS(ctx->opcode) == rA(ctx->opcode) && uimm == 0) {
/* NOP */
/* XXX: should handle special NOPs for POWER series */
return;
}
tcg_gen_ori_tl(cpu_gpr[rA(ctx->opcode)], cpu_gpr[rS(ctx->opcode)], uimm);