[PATCH v2 05/14] powerpc/pseries/ras: avoid calling rtas_token in NMI paths

[Nicholas Piggin]

Christophe Leroy's on April 4, 2020 12:30 am:
> 
> 
> Le 03/04/2020 à 15:26, Nicholas Piggin a écrit :
>> In the interest of reducing code and possible failures in the
>> machine check and system reset paths, grab the "ibm,nmi-interlock"
>> token at init time.
>> 
>> Reviewed-by: Mahesh Salgaonkar <mahesh at linux.ibm.com>
>> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
>> ---
>>   arch/powerpc/include/asm/firmware.h    |  1 +
>>   arch/powerpc/platforms/pseries/ras.c   |  2 +-
>>   arch/powerpc/platforms/pseries/setup.c | 13 ++++++++++---
>>   3 files changed, 12 insertions(+), 4 deletions(-)
>> 
>> diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
>> index ca33f4ef6cb4..6003c2e533a0 100644
>> --- a/arch/powerpc/include/asm/firmware.h
>> +++ b/arch/powerpc/include/asm/firmware.h
>> @@ -128,6 +128,7 @@ extern void machine_check_fwnmi(void);
>>   
>>   /* This is true if we are using the firmware NMI handler (typically LPAR) */
>>   extern int fwnmi_active;
>> +extern int ibm_nmi_interlock_token;
>>   
>>   extern unsigned int __start___fw_ftr_fixup, __stop___fw_ftr_fixup;
>>   
>> diff --git a/arch/powerpc/platforms/pseries/ras.c b/arch/powerpc/platforms/pseries/ras.c
>> index 1d7f973c647b..c74d5e740922 100644
>> --- a/arch/powerpc/platforms/pseries/ras.c
>> +++ b/arch/powerpc/platforms/pseries/ras.c
>> @@ -458,7 +458,7 @@ static struct rtas_error_log *fwnmi_get_errinfo(struct pt_regs *regs)
>>    */
>>   static void fwnmi_release_errinfo(void)
>>   {
>> -	int ret = rtas_call(rtas_token("ibm,nmi-interlock"), 0, 1, NULL);
>> +	int ret = rtas_call(ibm_nmi_interlock_token, 0, 1, NULL);
>>   	if (ret != 0)
>>   		printk(KERN_ERR "FWNMI: nmi-interlock failed: %d\n", ret);
>>   }
>> diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
>> index 0c8421dd01ab..b582198be284 100644
>> --- a/arch/powerpc/platforms/pseries/setup.c
>> +++ b/arch/powerpc/platforms/pseries/setup.c
>> @@ -83,6 +83,7 @@ unsigned long CMO_PageSize = (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K);
>>   EXPORT_SYMBOL(CMO_PageSize);
>>   
>>   int fwnmi_active;  /* TRUE if an FWNMI handler is present */
>> +int ibm_nmi_interlock_token;
>>   
>>   static void pSeries_show_cpuinfo(struct seq_file *m)
>>   {
>> @@ -113,9 +114,14 @@ static void __init fwnmi_init(void)
>>   	struct slb_entry *slb_ptr;
>>   	size_t size;
>>   #endif
>> +	int ibm_nmi_register_token;
>>   
>> -	int ibm_nmi_register = rtas_token("ibm,nmi-register");
>> -	if (ibm_nmi_register == RTAS_UNKNOWN_SERVICE)
>> +	ibm_nmi_register_token = rtas_token("ibm,nmi-register");
>> +	if (ibm_nmi_register_token == RTAS_UNKNOWN_SERVICE)
>> +		return;
>> +
>> +	ibm_nmi_interlock_token = rtas_token("ibm,nmi-interlock");
>> +	if (WARN_ON(ibm_nmi_interlock_token == RTAS_UNKNOWN_SERVICE))
>>   		return;
>>   
>>   	/* If the kernel's not linked at zero we point the firmware at low
>> @@ -123,7 +129,8 @@ static void __init fwnmi_init(void)
>>   	system_reset_addr  = __pa(system_reset_fwnmi) - PHYSICAL_START;
>>   	machine_check_addr = __pa(machine_check_fwnmi) - PHYSICAL_START;
>>   
>> -	if (0 == rtas_call(ibm_nmi_register, 2, 1, NULL, system_reset_addr,
>> +	if (0 == rtas_call(ibm_nmi_register_token, 2, 1, NULL,
>> +				system_reset_addr,
>>   				machine_check_addr))
> 
> Alignment is wrong.
> And you could put system_reset_addr and 
> machine_check_addr on the same line to limit the number of lines of the if.

I don't really like using spaces to align but I'll put it on the same 
line.

Thanks,
Nick