On 10/3/2013 10:15 AM, Ingo Molnar wrote:
>
> * Mike Travis <tra...@sgi.com> wrote:
>
>>
>>
>> On 10/3/2013 9:51 AM, Ingo Molnar wrote:
>>>
>>> * Mike Travis <tra...@sgi.com> wrote:
>>>
>>>> Some code added to the debug_core module had KDB dependencies
>>>> that it shouldn't have.
>>>>
>>>> Signed-off-by: Mike Travis <tra...@sgi.com>
>>>> ---
>>>> kernel/debug/debug_core.c | 8 ++++----
>>>> kernel/debug/debug_core.h | 2 ++
>>>> 2 files changed, 6 insertions(+), 4 deletions(-)
>>>>
>>>> --- linux.orig/kernel/debug/debug_core.c
>>>> +++ linux/kernel/debug/debug_core.c
>>>> @@ -575,8 +575,8 @@ return_normal:
>>>> raw_spin_lock(&dbg_slave_lock);
>>>>
>>>> #ifdef CONFIG_SMP
>>>> - /* If SYSTEM_NMI, slaves are already waiting */
>>>> - if (ks->err_code == KDB_REASON_SYSTEM_NMI)
>>>> + /* If send_ready set, slaves are already waiting */
>>>> + if (ks->send_ready)
>>>> atomic_set(ks->send_ready, 1);
>>>>
>>>> /* Signal the other CPUs to enter kgdb_wait() */
>>>> @@ -682,11 +682,11 @@ kgdb_handle_exception(int evector, int s
>>>> if (arch_kgdb_ops.enable_nmi)
>>>> arch_kgdb_ops.enable_nmi(0);
>>>>
>>>> + memset(ks, 0, sizeof(struct kgdb_state));
>>>> ks->cpu = raw_smp_processor_id();
>>>> ks->ex_vector = evector;
>>>> ks->signo = signo;
>>>> ks->err_code = ecode;
>>>> - ks->kgdb_usethreadid = 0;
>>>> ks->linux_regs = regs;
>>>>
>>>> if (kgdb_reenter_check(ks))
>>>> @@ -750,7 +750,7 @@ int kgdb_nmicallin(int cpu, int trapnr,
>>>> ks->cpu = cpu;
>>>> ks->ex_vector = trapnr;
>>>> ks->signo = SIGTRAP;
>>>> - ks->err_code = KDB_REASON_SYSTEM_NMI;
>>>> + ks->err_code = KGDB_KDB_REASON_SYSTEM_NMI;
>>>> ks->linux_regs = regs;
>>>> ks->send_ready = send_ready;
>>>> kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
>>>> --- linux.orig/kernel/debug/debug_core.h
>>>> +++ linux/kernel/debug/debug_core.h
>>>> @@ -75,11 +75,13 @@ extern int kdb_stub(struct kgdb_state *k
>>>> extern int kdb_parse(const char *cmdstr);
>>>> extern int kdb_common_init_state(struct kgdb_state *ks);
>>>> extern int kdb_common_deinit_state(void);
>>>> +#define KGDB_KDB_REASON_SYSTEM_NMI KDB_REASON_SYSTEM_NMI
>>>> #else /* ! CONFIG_KGDB_KDB */
>>>> static inline int kdb_stub(struct kgdb_state *ks)
>>>> {
>>>> return DBG_PASS_EVENT;
>>>> }
>>>> +#define KGDB_KDB_REASON_SYSTEM_NMI 0
>>>> #endif /* CONFIG_KGDB_KDB */
>>>>
>>>> #endif /* _DEBUG_CORE_H_ */
>>>
>>> Hm, the KGDB_KDB_REASON_SYSTEM_NMI definition is a bit ugly. I still think
>>> there are layering violations here and just kludging it around doesn't
>>> solve it - a helper function that keeps kgdb details to the kgdb code
>>> would.
>>>
>>> Anyway, if Jason is fine with this solution and upholds his Acked-by then
>>> I'll merge this into the first patch and apply the two patches.
>>>
>>> Thanks,
>>>
>>> Ingo
>>>
>>
>> Would you prefer a simple #ifdef CONFIG_KGDB_KDB around the assignment?
>
> An #ifdef doesn't solve the layering violation!
>
> kernel/debug/debug_core.c didn't have any serious use of #ifdef
> CONFIG_KGDB_KDB before (it used it to flavor a few printks) and I'm not
> convinced it needs one for this feature either.
>
> So if that whole chunk is kdb dependent, why not shuffle that into a
> nicely named function and host it somewhere appropriate in
> kernel/debug/kdb/? That function would turn into an empty inline function
> in the !CONFIG_KGDB_KDB case.
>
> But ... it's up to Jason really whether he wants to abstract that piece of
> code out, I'm just kibitzing here really.
>
> Thanks,
>
> Ingo
>
If I moved it to KDB then we would lose the capability to enter KGDB
mode and the gdb_stub functionality. The #ifdef could have a comment
to this effect?
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