[PATCH 1/6] arm64: Add macros to manage processor debug state

[Vijay Kilari]

On Wed, Jan 22, 2014 at 11:01 PM, Will Deacon <will.deacon at arm.com> wrote:
> Hello,
>
> On Wed, Jan 22, 2014 at 02:42:48PM +0000, vijay.kilari at gmail.com wrote:
>> From: Vijaya Kumar K <Vijaya.Kumar at caviumnetworks.com>
>>
>> Add macros to enable and disable to manage PSTATE.D
>> for debugging. The macros local_dbg_save and local_dbg_restore
>> are moved to irqflags.h file
>>
>> KGDB boot tests fail because of PSTATE.D is masked.
>> unmask it for debugging support
>>
>> Signed-off-by: Vijaya Kumar K <Vijaya.Kumar at caviumnetworks.com>
>> ---
>>  arch/arm64/include/asm/debug-monitors.h |   18 ++----------------
>>  arch/arm64/include/asm/irqflags.h       |   22 ++++++++++++++++++++++
>>  arch/arm64/kernel/debug-monitors.c      |    3 ++-
>>  3 files changed, 26 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
>> index 6231479..bc48880 100644
>> --- a/arch/arm64/include/asm/debug-monitors.h
>> +++ b/arch/arm64/include/asm/debug-monitors.h
>> @@ -43,22 +43,8 @@ enum debug_el {
>>  #ifndef __ASSEMBLY__
>>  struct task_struct;
>>
>> -#define local_dbg_save(flags)                                                        \
>> -     do {                                                                    \
>> -             typecheck(unsigned long, flags);                                \
>> -             asm volatile(                                                   \
>> -             "mrs    %0, daif                        // local_dbg_save\n"    \
>> -             "msr    daifset, #8"                                            \
>> -             : "=r" (flags) : : "memory");                                   \
>> -     } while (0)
>> -
>> -#define local_dbg_restore(flags)                                             \
>> -     do {                                                                    \
>> -             typecheck(unsigned long, flags);                                \
>> -             asm volatile(                                                   \
>> -             "msr    daif, %0                        // local_dbg_restore\n" \
>> -             : : "r" (flags) : "memory");                                    \
>> -     } while (0)
>> +#define local_dbg_enable()   asm("msr        daifclr, #8" : : : "memory")
>> +#define local_dbg_disable()  asm("msr        daifset, #8" : : : "memory")
>
> Any reason not to move these to irqflags.h too?

Can me moved to irqflags.h file
>
>>  #define DBG_ARCH_ID_RESERVED 0       /* In case of ptrace ABI updates. */
>>
>> diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
>> index b2fcfbc..f163b11 100644
>> --- a/arch/arm64/include/asm/irqflags.h
>> +++ b/arch/arm64/include/asm/irqflags.h
>> @@ -90,5 +90,27 @@ static inline int arch_irqs_disabled_flags(unsigned long flags)
>>       return flags & PSR_I_BIT;
>>  }
>>
>> +/*
>> + * save and restore debug state
>> + */
>> +static inline unsigned long local_dbg_save(void)
>> +{
>> +     unsigned long flags;
>> +     asm volatile(
>> +             "mrs    %0, daif                // local_dbg_save"
>> +             "msr    daifset, #8"
>> +             : "=r" (flags) : : "memory");
>> +     return flags;
>> +}
>> +
>> +static inline void local_dbg_restore(unsigned long flags)
>> +{
>> +     asm volatile(
>> +             "msr    daif, %0        // local_dbg_restore"
>> +             :
>> +             : "r" (flags)
>> +             : "memory");
>> +}
>> +
>>  #endif
>>  #endif
>> diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c
>> index 23586bd..774ad04 100644
>> --- a/arch/arm64/kernel/debug-monitors.c
>> +++ b/arch/arm64/kernel/debug-monitors.c
>> @@ -51,7 +51,7 @@ u8 debug_monitors_arch(void)
>>  static void mdscr_write(u32 mdscr)
>>  {
>>       unsigned long flags;
>> -     local_dbg_save(flags);
>> +     flags = local_dbg_save();
>
> Why are you changing the API? This is now pointlessly different to irqs.

To be in line with arch_local_irq_save & arch_local_save_flags in irqflags.h,
I moved this macros into functions and accordingly changed the caller.
I could not find any code using this local_dbg_{save, restore} except
from debug-monitors.c file

If required, I can think of renaming local_dbg_{save,restore} as
local_dbg_{save,restore}_flags

>
> Will