On 10/3/2013 10:53 AM, Mike Travis wrote:
>
>
> 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?
>
Another option would be to pass the code in as the caller knows if KDB
is defined or not?
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