linux-kernel - Re: [PATCH 1/1] PATCH: KGDB/KDB Fix no KDB config problem.

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Date:	Thu, 03 Oct 2013 10:04:01 -0700
From:	Mike Travis <travis@....com>
To:	Ingo Molnar <mingo@...nel.org>
CC:	Ingo Molnar <mingo@...hat.com>,
	Jason Wessel <jason.wessel@...driver.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Paul Mackerras <paulus@...ba.org>,
	Arnaldo Carvalho de Melo <acme@...stprotocols.net>,
	"H. Peter Anvin" <hpa@...or.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Dimitri Sivanich <sivanich@....com>,
	Hedi Berriche <hedi@....com>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] PATCH: KGDB/KDB Fix no KDB config problem.



On 10/3/2013 9:51 AM, Ingo Molnar wrote:
> 
> * Mike Travis <travis@....com> wrote:
> 
>> Some code added to the debug_core module had KDB dependencies
>> that it shouldn't have.
>>
>> Signed-off-by: Mike Travis <travis@....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?
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