2020-04-01 06:14:58

by Ravi Bangoria

Subject: [PATCH v2 06/16] powerpc/watchpoint: Provide DAWR number to __set_breakpoint

Introduce new parameter 'nr' to __set_breakpoint() which indicates
which DAWR should be programed. Also convert current_brk variable
to an array.

Signed-off-by: Ravi Bangoria <[email protected]>
---
arch/powerpc/include/asm/debug.h | 2 +-
arch/powerpc/include/asm/hw_breakpoint.h | 2 +-
arch/powerpc/kernel/hw_breakpoint.c | 8 ++++----
arch/powerpc/kernel/process.c | 14 +++++++-------
arch/powerpc/kernel/signal.c | 2 +-
arch/powerpc/xmon/xmon.c | 2 +-
6 files changed, 15 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
index 7756026b95ca..6228935a8b64 100644
--- a/arch/powerpc/include/asm/debug.h
+++ b/arch/powerpc/include/asm/debug.h
@@ -45,7 +45,7 @@ static inline int debugger_break_match(struct pt_regs *regs) { return 0; }
static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
#endif

-void __set_breakpoint(struct arch_hw_breakpoint *brk);
+void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr);
bool ppc_breakpoint_available(void);
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
extern void do_send_trap(struct pt_regs *regs, unsigned long address,
diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
index 62549007c87a..4e4976c3248b 100644
--- a/arch/powerpc/include/asm/hw_breakpoint.h
+++ b/arch/powerpc/include/asm/hw_breakpoint.h
@@ -85,7 +85,7 @@ static inline void hw_breakpoint_disable(void)
brk.len = 0;
brk.hw_len = 0;
if (ppc_breakpoint_available())
- __set_breakpoint(&brk);
+ __set_breakpoint(&brk, 0);
}
extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
int hw_breakpoint_handler(struct die_args *args);
diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
index 4120349e2abe..7562f9ceb77e 100644
--- a/arch/powerpc/kernel/hw_breakpoint.c
+++ b/arch/powerpc/kernel/hw_breakpoint.c
@@ -63,7 +63,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
* If so, DABR will be populated in single_step_dabr_instruction().
*/
if (current->thread.last_hit_ubp != bp)
- __set_breakpoint(info);
+ __set_breakpoint(info, 0);

return 0;
}
@@ -221,7 +221,7 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)

info = counter_arch_bp(tsk->thread.last_hit_ubp);
regs->msr &= ~MSR_SE;
- __set_breakpoint(info);
+ __set_breakpoint(info, 0);
tsk->thread.last_hit_ubp = NULL;
}

@@ -346,7 +346,7 @@ int hw_breakpoint_handler(struct die_args *args)
if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
perf_bp_event(bp, regs);

- __set_breakpoint(info);
+ __set_breakpoint(info, 0);
out:
rcu_read_unlock();
return rc;
@@ -379,7 +379,7 @@ static int single_step_dabr_instruction(struct die_args *args)
if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
perf_bp_event(bp, regs);

- __set_breakpoint(info);
+ __set_breakpoint(info, 0);
current->thread.last_hit_ubp = NULL;

/*
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index b548a584e465..e0275fcd0c55 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -630,7 +630,7 @@ void do_break (struct pt_regs *regs, unsigned long address,
}
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */

-static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk);
+static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk[HBP_NUM_MAX]);

#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/*
@@ -707,7 +707,7 @@ EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
static void set_breakpoint(struct arch_hw_breakpoint *brk)
{
preempt_disable();
- __set_breakpoint(brk);
+ __set_breakpoint(brk, 0);
preempt_enable();
}

@@ -793,13 +793,13 @@ static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
return 0;
}

-void __set_breakpoint(struct arch_hw_breakpoint *brk)
+void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr)
{
- memcpy(this_cpu_ptr(&current_brk), brk, sizeof(*brk));
+ memcpy(this_cpu_ptr(&current_brk[nr]), brk, sizeof(*brk));

if (dawr_enabled())
// Power8 or later
- set_dawr(brk, 0);
+ set_dawr(brk, nr);
else if (IS_ENABLED(CONFIG_PPC_8xx))
set_breakpoint_8xx(brk);
else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
@@ -1167,8 +1167,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
* schedule DABR
*/
#ifndef CONFIG_HAVE_HW_BREAKPOINT
- if (unlikely(!hw_brk_match(this_cpu_ptr(&current_brk), &new->thread.hw_brk)))
- __set_breakpoint(&new->thread.hw_brk);
+ if (unlikely(!hw_brk_match(this_cpu_ptr(&current_brk[0]), &new->thread.hw_brk)))
+ __set_breakpoint(&new->thread.hw_brk, 0);
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif

diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
index d215f9554553..bbf237f072d4 100644
--- a/arch/powerpc/kernel/signal.c
+++ b/arch/powerpc/kernel/signal.c
@@ -129,7 +129,7 @@ static void do_signal(struct task_struct *tsk)
* triggered inside the kernel.
*/
if (tsk->thread.hw_brk.address && tsk->thread.hw_brk.type)
- __set_breakpoint(&tsk->thread.hw_brk);
+ __set_breakpoint(&tsk->thread.hw_brk, 0);
#endif
/* Re-enable the breakpoints for the signal stack */
thread_change_pc(tsk, tsk->thread.regs);
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 75ca41c04dd1..508d353e7f06 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -935,7 +935,7 @@ static void insert_cpu_bpts(void)
brk.address = dabr.address;
brk.type = (dabr.enabled & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
brk.len = DABR_MAX_LEN;
- __set_breakpoint(&brk);
+ __set_breakpoint(&brk, 0);
}

if (iabr)
--
2.21.1

2020-04-01 07:04:13

by Christophe Leroy

Subject: Re: [PATCH v2 06/16] powerpc/watchpoint: Provide DAWR number to __set_breakpoint

Le 01/04/2020 à 08:12, Ravi Bangoria a écrit :
> Introduce new parameter 'nr' to __set_breakpoint() which indicates
> which DAWR should be programed. Also convert current_brk variable
> to an array.
>
> Signed-off-by: Ravi Bangoria <[email protected]>
> ---
> arch/powerpc/include/asm/debug.h | 2 +-
> arch/powerpc/include/asm/hw_breakpoint.h | 2 +-
> arch/powerpc/kernel/hw_breakpoint.c | 8 ++++----
> arch/powerpc/kernel/process.c | 14 +++++++-------
> arch/powerpc/kernel/signal.c | 2 +-
> arch/powerpc/xmon/xmon.c | 2 +-
> 6 files changed, 15 insertions(+), 15 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
> index 7756026b95ca..6228935a8b64 100644
> --- a/arch/powerpc/include/asm/debug.h
> +++ b/arch/powerpc/include/asm/debug.h
> @@ -45,7 +45,7 @@ static inline int debugger_break_match(struct pt_regs *regs) { return 0; }
> static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
> #endif
>
> -void __set_breakpoint(struct arch_hw_breakpoint *brk);
> +void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr);

Same, I think it would make more sense to have nr as first argument.

Christophe


> bool ppc_breakpoint_available(void);
> #ifdef CONFIG_PPC_ADV_DEBUG_REGS
> extern void do_send_trap(struct pt_regs *regs, unsigned long address,
> diff --git a/arch/powerpc/include/asm/hw_breakpoint.h b/arch/powerpc/include/asm/hw_breakpoint.h
> index 62549007c87a..4e4976c3248b 100644
> --- a/arch/powerpc/include/asm/hw_breakpoint.h
> +++ b/arch/powerpc/include/asm/hw_breakpoint.h
> @@ -85,7 +85,7 @@ static inline void hw_breakpoint_disable(void)
> brk.len = 0;
> brk.hw_len = 0;
> if (ppc_breakpoint_available())
> - __set_breakpoint(&brk);
> + __set_breakpoint(&brk, 0);
> }
> extern void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs);
> int hw_breakpoint_handler(struct die_args *args);
> diff --git a/arch/powerpc/kernel/hw_breakpoint.c b/arch/powerpc/kernel/hw_breakpoint.c
> index 4120349e2abe..7562f9ceb77e 100644
> --- a/arch/powerpc/kernel/hw_breakpoint.c
> +++ b/arch/powerpc/kernel/hw_breakpoint.c
> @@ -63,7 +63,7 @@ int arch_install_hw_breakpoint(struct perf_event *bp)
> * If so, DABR will be populated in single_step_dabr_instruction().
> */
> if (current->thread.last_hit_ubp != bp)
> - __set_breakpoint(info);
> + __set_breakpoint(info, 0);
>
> return 0;
> }
> @@ -221,7 +221,7 @@ void thread_change_pc(struct task_struct *tsk, struct pt_regs *regs)
>
> info = counter_arch_bp(tsk->thread.last_hit_ubp);
> regs->msr &= ~MSR_SE;
> - __set_breakpoint(info);
> + __set_breakpoint(info, 0);
> tsk->thread.last_hit_ubp = NULL;
> }
>
> @@ -346,7 +346,7 @@ int hw_breakpoint_handler(struct die_args *args)
> if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
> perf_bp_event(bp, regs);
>
> - __set_breakpoint(info);
> + __set_breakpoint(info, 0);
> out:
> rcu_read_unlock();
> return rc;
> @@ -379,7 +379,7 @@ static int single_step_dabr_instruction(struct die_args *args)
> if (!(info->type & HW_BRK_TYPE_EXTRANEOUS_IRQ))
> perf_bp_event(bp, regs);
>
> - __set_breakpoint(info);
> + __set_breakpoint(info, 0);
> current->thread.last_hit_ubp = NULL;
>
> /*
> diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
> index b548a584e465..e0275fcd0c55 100644
> --- a/arch/powerpc/kernel/process.c
> +++ b/arch/powerpc/kernel/process.c
> @@ -630,7 +630,7 @@ void do_break (struct pt_regs *regs, unsigned long address,
> }
> #endif /* CONFIG_PPC_ADV_DEBUG_REGS */
>
> -static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk);
> +static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk[HBP_NUM_MAX]);
>
> #ifdef CONFIG_PPC_ADV_DEBUG_REGS
> /*
> @@ -707,7 +707,7 @@ EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
> static void set_breakpoint(struct arch_hw_breakpoint *brk)
> {
> preempt_disable();
> - __set_breakpoint(brk);
> + __set_breakpoint(brk, 0);
> preempt_enable();
> }
>
> @@ -793,13 +793,13 @@ static inline int set_breakpoint_8xx(struct arch_hw_breakpoint *brk)
> return 0;
> }
>
> -void __set_breakpoint(struct arch_hw_breakpoint *brk)
> +void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr)
> {
> - memcpy(this_cpu_ptr(&current_brk), brk, sizeof(*brk));
> + memcpy(this_cpu_ptr(&current_brk[nr]), brk, sizeof(*brk));
>
> if (dawr_enabled())
> // Power8 or later
> - set_dawr(brk, 0);
> + set_dawr(brk, nr);
> else if (IS_ENABLED(CONFIG_PPC_8xx))
> set_breakpoint_8xx(brk);
> else if (!cpu_has_feature(CPU_FTR_ARCH_207S))
> @@ -1167,8 +1167,8 @@ struct task_struct *__switch_to(struct task_struct *prev,
> * schedule DABR
> */
> #ifndef CONFIG_HAVE_HW_BREAKPOINT
> - if (unlikely(!hw_brk_match(this_cpu_ptr(&current_brk), &new->thread.hw_brk)))
> - __set_breakpoint(&new->thread.hw_brk);
> + if (unlikely(!hw_brk_match(this_cpu_ptr(&current_brk[0]), &new->thread.hw_brk)))
> + __set_breakpoint(&new->thread.hw_brk, 0);
> #endif /* CONFIG_HAVE_HW_BREAKPOINT */
> #endif
>
> diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c
> index d215f9554553..bbf237f072d4 100644
> --- a/arch/powerpc/kernel/signal.c
> +++ b/arch/powerpc/kernel/signal.c
> @@ -129,7 +129,7 @@ static void do_signal(struct task_struct *tsk)
> * triggered inside the kernel.
> */
> if (tsk->thread.hw_brk.address && tsk->thread.hw_brk.type)
> - __set_breakpoint(&tsk->thread.hw_brk);
> + __set_breakpoint(&tsk->thread.hw_brk, 0);
> #endif
> /* Re-enable the breakpoints for the signal stack */
> thread_change_pc(tsk, tsk->thread.regs);
> diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
> index 75ca41c04dd1..508d353e7f06 100644
> --- a/arch/powerpc/xmon/xmon.c
> +++ b/arch/powerpc/xmon/xmon.c
> @@ -935,7 +935,7 @@ static void insert_cpu_bpts(void)
> brk.address = dabr.address;
> brk.type = (dabr.enabled & HW_BRK_TYPE_DABR) | HW_BRK_TYPE_PRIV_ALL;
> brk.len = DABR_MAX_LEN;
> - __set_breakpoint(&brk);
> + __set_breakpoint(&brk, 0);
> }
>
> if (iabr)
>

2020-04-01 08:59:30

by Ravi Bangoria

Subject: Re: [PATCH v2 06/16] powerpc/watchpoint: Provide DAWR number to __set_breakpoint

On 4/1/20 12:33 PM, Christophe Leroy wrote:
>
>
> Le 01/04/2020 à 08:12, Ravi Bangoria a écrit :
>> Introduce new parameter 'nr' to __set_breakpoint() which indicates
>> which DAWR should be programed. Also convert current_brk variable
>> to an array.
>>
>> Signed-off-by: Ravi Bangoria <[email protected]>
>> ---
>>   arch/powerpc/include/asm/debug.h         |  2 +-
>>   arch/powerpc/include/asm/hw_breakpoint.h |  2 +-
>>   arch/powerpc/kernel/hw_breakpoint.c      |  8 ++++----
>>   arch/powerpc/kernel/process.c            | 14 +++++++-------
>>   arch/powerpc/kernel/signal.c             |  2 +-
>>   arch/powerpc/xmon/xmon.c                 |  2 +-
>>   6 files changed, 15 insertions(+), 15 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/debug.h b/arch/powerpc/include/asm/debug.h
>> index 7756026b95ca..6228935a8b64 100644
>> --- a/arch/powerpc/include/asm/debug.h
>> +++ b/arch/powerpc/include/asm/debug.h
>> @@ -45,7 +45,7 @@ static inline int debugger_break_match(struct pt_regs *regs) { return 0; }
>>   static inline int debugger_fault_handler(struct pt_regs *regs) { return 0; }
>>   #endif
>> -void __set_breakpoint(struct arch_hw_breakpoint *brk);
>> +void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr);
>
> Same, I think it would make more sense to have nr as first argument.

Sorry, didn't get your point. How will that help?

Ravi

2020-04-01 09:13:19

by Christophe Leroy

Subject: Re: [PATCH v2 06/16] powerpc/watchpoint: Provide DAWR number to __set_breakpoint

Le 01/04/2020 à 10:57, Ravi Bangoria a écrit :
>
>
> On 4/1/20 12:33 PM, Christophe Leroy wrote:
>>
>>
>> Le 01/04/2020 à 08:12, Ravi Bangoria a écrit :
>>> Introduce new parameter 'nr' to __set_breakpoint() which indicates
>>> which DAWR should be programed. Also convert current_brk variable
>>> to an array.
>>>
>>> Signed-off-by: Ravi Bangoria <[email protected]>
>>> ---
>>>   arch/powerpc/include/asm/debug.h         |  2 +-
>>>   arch/powerpc/include/asm/hw_breakpoint.h |  2 +-
>>>   arch/powerpc/kernel/hw_breakpoint.c      |  8 ++++----
>>>   arch/powerpc/kernel/process.c            | 14 +++++++-------
>>>   arch/powerpc/kernel/signal.c             |  2 +-
>>>   arch/powerpc/xmon/xmon.c                 |  2 +-
>>>   6 files changed, 15 insertions(+), 15 deletions(-)
>>>
>>> diff --git a/arch/powerpc/include/asm/debug.h
>>> b/arch/powerpc/include/asm/debug.h
>>> index 7756026b95ca..6228935a8b64 100644
>>> --- a/arch/powerpc/include/asm/debug.h
>>> +++ b/arch/powerpc/include/asm/debug.h
>>> @@ -45,7 +45,7 @@ static inline int debugger_break_match(struct
>>> pt_regs *regs) { return 0; }
>>>   static inline int debugger_fault_handler(struct pt_regs *regs) {
>>> return 0; }
>>>   #endif
>>> -void __set_breakpoint(struct arch_hw_breakpoint *brk);
>>> +void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr);
>>
>> Same, I think it would make more sense to have nr as first argument.
>
> Sorry, didn't get your point. How will that help?
>

Well, it is a tiny detail but for me it is more natural to first tel
which element you modify before telling how you modify it.

Christophe

2020-04-01 10:09:27

by Christophe Leroy

Subject: Re: [PATCH v2 06/16] powerpc/watchpoint: Provide DAWR number to __set_breakpoint

Le 01/04/2020 à 11:11, Christophe Leroy a écrit :
>
>
> Le 01/04/2020 à 10:57, Ravi Bangoria a écrit :
>>
>>
>> On 4/1/20 12:33 PM, Christophe Leroy wrote:
>>>
>>>
>>> Le 01/04/2020 à 08:12, Ravi Bangoria a écrit :
>>>> Introduce new parameter 'nr' to __set_breakpoint() which indicates
>>>> which DAWR should be programed. Also convert current_brk variable
>>>> to an array.
>>>>
>>>> Signed-off-by: Ravi Bangoria <[email protected]>
>>>> ---
>>>>   arch/powerpc/include/asm/debug.h         |  2 +-
>>>>   arch/powerpc/include/asm/hw_breakpoint.h |  2 +-
>>>>   arch/powerpc/kernel/hw_breakpoint.c      |  8 ++++----
>>>>   arch/powerpc/kernel/process.c            | 14 +++++++-------
>>>>   arch/powerpc/kernel/signal.c             |  2 +-
>>>>   arch/powerpc/xmon/xmon.c                 |  2 +-
>>>>   6 files changed, 15 insertions(+), 15 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/include/asm/debug.h
>>>> b/arch/powerpc/include/asm/debug.h
>>>> index 7756026b95ca..6228935a8b64 100644
>>>> --- a/arch/powerpc/include/asm/debug.h
>>>> +++ b/arch/powerpc/include/asm/debug.h
>>>> @@ -45,7 +45,7 @@ static inline int debugger_break_match(struct
>>>> pt_regs *regs) { return 0; }
>>>>   static inline int debugger_fault_handler(struct pt_regs *regs) {
>>>> return 0; }
>>>>   #endif
>>>> -void __set_breakpoint(struct arch_hw_breakpoint *brk);
>>>> +void __set_breakpoint(struct arch_hw_breakpoint *brk, int nr);
>>>
>>> Same, I think it would make more sense to have nr as first argument.
>>
>> Sorry, didn't get your point. How will that help?
>>
>
> Well, it is a tiny detail but for me it is more natural to first tel
> which element you modify before telling how you modify it.
>

And the second advantage is that when you have a function
get_something() paired with you set_something(), you can then have it as
first argument in both functions.

void set_something(int nr, type something)
type get_something(int nr)

But again, that's detail, so up to you.

Christophe