Commit b68e60e6 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by David Gibson
Browse files

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: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent c409bc5d

target-ppc/translate.c

+18 −3
Original line number Diff line number Diff line
@@ -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);