Re: [coreboot] Broadwell-DE hang in coreboot: mp_init.c

[Zeh, Werner]

Hi Mark.

I saw a very similar issue (similar because I have not analyzed it in detail due to missing time) with a 6 core Broadwell-DE. It hangs as well in SMM relocation.
Same mainboard and coreboot binary with a 4 core Broadwell-DE does not have this effect.

Werner
> Von: coreboot [mailto:[e-mail]] Im Auftrag von mark pleso via coreboot
> Gesendet: Montag, 26. Februar 2018 23:40
> An: [e-mail]
> Betreff: [coreboot] Broadwell-DE hang in coreboot: mp_init.c
>
> Has anyone else seen a hang during coreboot booting on a Broadwell-DE?  The issue appears to be in mp_init.c, in the function smm_do_relocation().  This is coreboot 4.7, but I think the issue exists in 4.6 >as well.
>
> Enabling the printk will stop the hang. Or, just adding a wbinvd() instruction will stop the hang, and things proceed normally.  Code is below.
>
> Any help would be appreciated.
>
> btw - This not a commercial motherboard.
>
> coreboot/src/cpu/x86/mp_init.c
> static void asmlinkage smm_do_relocation(void *arg)
> {
>         const struct smm_module_params *p;
>       const struct smm_runtime *runtime;
>       int cpu;
>         uintptr_t curr_smbase;
>         uintptr_t perm_smbase;
>
> p = arg;
>         runtime = p->runtime;
>         cpu = p->cpu;
>         curr_smbase = runtime->smbase;
>
> if (cpu >= CONFIG_MAX_CPUS) {
>                 printk(BIOS_CRIT,
>                        "Invalid CPU number assigned in SMM stub: %d\n", cpu);
>                 return;
>         }
>
> /*
>          * The permanent handler runs with all cpus concurrently. Precalculate
>          * the location of the new SMBASE. If using SMM modules then this
>          * calculation needs to match that of the module loader.
>          */
>         perm_smbase = mp_state.perm_smbase;
>         perm_smbase -= cpu * runtime->save_state_size;
>
> printk(BIOS_DEBUG, "New SMBASE 0x%08lx\n", perm_smbase);
>
> /* write cache to DRAM before calling relocation handler */ /* will stop hang */
>         wbinvd();  /* <<=== OR NEW INSTRUCTION w/o printk STOPS HANG */
>
> /* Setup code checks this callback for validity. */
>         mp_state.ops.relocation_handler(cpu, curr_smbase, perm_smbase);
> }