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

[Vijay Kilari]

Hi Wiil,

On Fri, Jan 24, 2014 at 10:09 PM, Will Deacon <will.deacon at arm.com> wrote:
> Hello,
>
> On Thu, Jan 23, 2014 at 03:29:07PM +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 |   17 -----------
>>  arch/arm64/include/asm/irqflags.h       |   48 +++++++++++++++++++++++++++++++
>>  arch/arm64/kernel/debug-monitors.c      |    1 +
>>  3 files changed, 49 insertions(+), 17 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/debug-monitors.h b/arch/arm64/include/asm/debug-monitors.h
>> index 6231479..ee9f28e 100644
>> --- a/arch/arm64/include/asm/debug-monitors.h
>> +++ b/arch/arm64/include/asm/debug-monitors.h
>> @@ -43,23 +43,6 @@ 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 DBG_ARCH_ID_RESERVED 0       /* In case of ptrace ABI updates. */
>>
>>  #define DBG_HOOK_HANDLED     0
>> diff --git a/arch/arm64/include/asm/irqflags.h b/arch/arm64/include/asm/irqflags.h
>> index b2fcfbc..f9b013e 100644
>> --- a/arch/arm64/include/asm/irqflags.h
>> +++ b/arch/arm64/include/asm/irqflags.h
>> @@ -90,5 +90,53 @@ static inline int arch_irqs_disabled_flags(unsigned long flags)
>>       return flags & PSR_I_BIT;
>>  }
>>
>> +/*
>> + * save and restore debug state
>> + */
>> +static inline unsigned long arch_local_dbg_save(void)
>> +{
>> +     unsigned long flags;
>> +     asm volatile(
>> +             "mrs    %0, daif        // arch_local_dbg_save"
>> +             "msr    daifset, #8"
>> +             : "=r" (flags) : : "memory");
>> +     return flags;
>> +}
>> +
>> +static inline void arch_local_dbg_restore(unsigned long flags)
>> +{
>> +     asm volatile(
>> +             "msr    daif, %0        // arch_local_dbg_restore"
>> +             :
>> +             : "r" (flags)
>> +             : "memory");
>> +}
>> +
>> +#define raw_local_dbg_save(flags)                    \
>> +     do {                                            \
>> +             typecheck(unsigned long, flags);        \
>> +             flags = arch_local_dbg_save();          \
>> +     } while (0)
>> +
>> +#define raw_local_dbg_restore(flags)                 \
>> +     do {                                            \
>> +             typecheck(unsigned long, flags);        \
>> +             arch_local_dbg_restore(flags);          \
>> +     } while (0)
>> +
>> +#define local_dbg_save(flags)                                \
>> +     do {                                            \
>> +             raw_local_dbg_save(flags);              \
>> +     } while (0)
>> +
>> +#define local_dbg_restore(flags)                     \
>> +     do {                                            \
>> +             typecheck(unsigned long, flags);        \
>> +             raw_local_dbg_restore(flags);           \
>> +     } while (0)
>
> Hehe, I think you took me a bit too literally when I said to follow what we
> do for irqs. This code is arm64-specific, so you don't need to construct it
> in the same way. All you need to do is *move* the existing code from
> debug-monitors.h to irqflags.h. That's it!
>
I have reposted the patch (v9) please review.

>> +#define local_dbg_enable()   asm("msr        daifclr, #8" : : : "memory")
>> +#define local_dbg_disable()  asm("msr        daifset, #8" : : : "memory")
>
> I'm also fine with adding these two.
>
> Will