Commit 154c69f2 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by David Gibson
Browse files

target/ppc: Fix nip on power management instructions 



Those instructions currently raise an exception from within
the helper. This tends to result in a bogus nip value in
the env context (typically the beginning of the TB). Such
a helper needs a gen_update_nip() first.

This fixes it with a different approach which is to throw the
exception from translate.c instead of the helper using
gen_exception_nip() which does the right thing. Exception
EXCP_HLT is also used instead of POWERPC_EXCP_STOP to effectively
exit from the CPU execution loop.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
[clg : modified the commit log to comment the use of EXCP_HLT instead
       of POWERPC_EXCP_STOP]
Signed-off-by: default avatarCédric Le Goater <clg@kaod.org>
Message-Id: <20190215161648.9600-2-clg@kaod.org>
Signed-off-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
parent ef80b99c

target/ppc/excp_helper.c

+0 −1
Original line number Diff line number Diff line
@@ -958,7 +958,6 @@ void helper_pminsn(CPUPPCState *env, powerpc_pm_insn_t insn) 
     * but this doesn't seem to be a problem.

     */

    env->msr |= (1ull << MSR_EE);

    raise_exception(env, EXCP_HLT);

}

#endif /* defined(TARGET_PPC64) */

target/ppc/translate.c

+8 −4
Original line number Diff line number Diff line
@@ -3566,7 +3566,8 @@ static void gen_doze(DisasContext *ctx) 
    t = tcg_const_i32(PPC_PM_DOZE);

    gen_helper_pminsn(cpu_env, t);

    tcg_temp_free_i32(t);

    gen_stop_exception(ctx);

    /* Stop translation, as the CPU is supposed to sleep from now */

    gen_exception_nip(ctx, EXCP_HLT, ctx->base.pc_next);

#endif /* defined(CONFIG_USER_ONLY) */

}
@@ -3581,7 +3582,8 @@ static void gen_nap(DisasContext *ctx) 
    t = tcg_const_i32(PPC_PM_NAP);

    gen_helper_pminsn(cpu_env, t);

    tcg_temp_free_i32(t);

    gen_stop_exception(ctx);

    /* Stop translation, as the CPU is supposed to sleep from now */

    gen_exception_nip(ctx, EXCP_HLT, ctx->base.pc_next);

#endif /* defined(CONFIG_USER_ONLY) */

}
@@ -3601,7 +3603,8 @@ static void gen_sleep(DisasContext *ctx) 
    t = tcg_const_i32(PPC_PM_SLEEP);

    gen_helper_pminsn(cpu_env, t);

    tcg_temp_free_i32(t);

    gen_stop_exception(ctx);

    /* Stop translation, as the CPU is supposed to sleep from now */

    gen_exception_nip(ctx, EXCP_HLT, ctx->base.pc_next);

#endif /* defined(CONFIG_USER_ONLY) */

}
@@ -3616,7 +3619,8 @@ static void gen_rvwinkle(DisasContext *ctx) 
    t = tcg_const_i32(PPC_PM_RVWINKLE);

    gen_helper_pminsn(cpu_env, t);

    tcg_temp_free_i32(t);

    gen_stop_exception(ctx);

    /* Stop translation, as the CPU is supposed to sleep from now */

    gen_exception_nip(ctx, EXCP_HLT, ctx->base.pc_next);

#endif /* defined(CONFIG_USER_ONLY) */

}

#endif /* #if defined(TARGET_PPC64) */