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[RFC V2 2/8] powerpc: Prepare to build with generic entry/exit framework

Mukesh Kumar Chaurasiya posted 8 patches 5 months ago
There is a newer version of this series
[RFC V2 2/8] powerpc: Prepare to build with generic entry/exit framework
Posted by Mukesh Kumar Chaurasiya 5 months ago 
Enabling build with generic entry/exit framework for powerpc
architecture requires few necessary steps.

Introducing minor infrastructure updates to prepare for future generic
framework handling:

- Add syscall_work field to struct thread_info for SYSCALL_WORK_* flags.
- Provide arch_syscall_is_vdso_sigreturn() stub, returning false.
- Add on_thread_stack() helper to test whether the current stack pointer
  lies within the task’s kernel stack.

No functional change is intended with this patch.

Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
---
 arch/powerpc/include/asm/entry-common.h | 11 +++++++++++
 arch/powerpc/include/asm/stacktrace.h   |  8 ++++++++
 arch/powerpc/include/asm/syscall.h      |  5 +++++
 arch/powerpc/include/asm/thread_info.h  |  1 +
 4 files changed, 25 insertions(+)
 create mode 100644 arch/powerpc/include/asm/entry-common.h

diff --git a/arch/powerpc/include/asm/entry-common.h b/arch/powerpc/include/asm/entry-common.h
new file mode 100644
index 0000000000000..3af16d821d07e
--- /dev/null
+++ b/arch/powerpc/include/asm/entry-common.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _ASM_PPC_ENTRY_COMMON_H
+#define _ASM_PPC_ENTRY_COMMON_H
+
+#ifdef CONFIG_GENERIC_IRQ_ENTRY
+
+#include <asm/stacktrace.h>
+
+#endif /* CONFIG_GENERIC_IRQ_ENTRY */
+#endif /* _ASM_PPC_ENTRY_COMMON_H */
diff --git a/arch/powerpc/include/asm/stacktrace.h b/arch/powerpc/include/asm/stacktrace.h
index 6149b53b3bc8e..3f0a242468813 100644
--- a/arch/powerpc/include/asm/stacktrace.h
+++ b/arch/powerpc/include/asm/stacktrace.h
@@ -8,6 +8,14 @@
 #ifndef _ASM_POWERPC_STACKTRACE_H
 #define _ASM_POWERPC_STACKTRACE_H
 
+#include <linux/sched.h>
+
 void show_user_instructions(struct pt_regs *regs);
 
+static inline bool on_thread_stack(void)
+{
+	return !(((unsigned long)(current->stack) ^ current_stack_pointer)
+			& ~(THREAD_SIZE -1));
+}
+
 #endif /* _ASM_POWERPC_STACKTRACE_H */
diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
index 4b3c52ed6e9d2..834fcc4f7b543 100644
--- a/arch/powerpc/include/asm/syscall.h
+++ b/arch/powerpc/include/asm/syscall.h
@@ -139,4 +139,9 @@ static inline int syscall_get_arch(struct task_struct *task)
 	else
 		return AUDIT_ARCH_PPC64;
 }
+
+static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
+{
+	return false;
+}
 #endif	/* _ASM_SYSCALL_H */
diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
index 2785c7462ebf7..d0e87c9bae0b0 100644
--- a/arch/powerpc/include/asm/thread_info.h
+++ b/arch/powerpc/include/asm/thread_info.h
@@ -54,6 +54,7 @@
 struct thread_info {
 	int		preempt_count;		/* 0 => preemptable,
 						   <0 => BUG */
+	unsigned long	syscall_work;		/* SYSCALL_WORK_ flags */
 #ifdef CONFIG_SMP
 	unsigned int	cpu;
 #endif
-- 
2.51.0
Re: [RFC V2 2/8] powerpc: Prepare to build with generic entry/exit framework
Posted by Shrikanth Hegde 4 months, 3 weeks ago 

On 9/9/25 2:32 AM, Mukesh Kumar Chaurasiya wrote:
> Enabling build with generic entry/exit framework for powerpc
> architecture requires few necessary steps.
> 
> Introducing minor infrastructure updates to prepare for future generic
> framework handling:
> 
> - Add syscall_work field to struct thread_info for SYSCALL_WORK_* flags.
> - Provide arch_syscall_is_vdso_sigreturn() stub, returning false.
> - Add on_thread_stack() helper to test whether the current stack pointer
>    lies within the task’s kernel stack.
> 
> No functional change is intended with this patch.
> 
> Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
> ---
>   arch/powerpc/include/asm/entry-common.h | 11 +++++++++++
>   arch/powerpc/include/asm/stacktrace.h   |  8 ++++++++
>   arch/powerpc/include/asm/syscall.h      |  5 +++++
>   arch/powerpc/include/asm/thread_info.h  |  1 +
>   4 files changed, 25 insertions(+)
>   create mode 100644 arch/powerpc/include/asm/entry-common.h
> 
> diff --git a/arch/powerpc/include/asm/entry-common.h b/arch/powerpc/include/asm/entry-common.h
> new file mode 100644
> index 0000000000000..3af16d821d07e
> --- /dev/null
> +++ b/arch/powerpc/include/asm/entry-common.h
> @@ -0,0 +1,11 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +
> +#ifndef _ASM_PPC_ENTRY_COMMON_H
> +#define _ASM_PPC_ENTRY_COMMON_H
> +
> +#ifdef CONFIG_GENERIC_IRQ_ENTRY
> +
> +#include <asm/stacktrace.h>
> +
> +#endif /* CONFIG_GENERIC_IRQ_ENTRY */
> +#endif /* _ASM_PPC_ENTRY_COMMON_H */
> diff --git a/arch/powerpc/include/asm/stacktrace.h b/arch/powerpc/include/asm/stacktrace.h
> index 6149b53b3bc8e..3f0a242468813 100644
> --- a/arch/powerpc/include/asm/stacktrace.h
> +++ b/arch/powerpc/include/asm/stacktrace.h
> @@ -8,6 +8,14 @@
>   #ifndef _ASM_POWERPC_STACKTRACE_H
>   #define _ASM_POWERPC_STACKTRACE_H
>   
> +#include <linux/sched.h>

nit:

Is sched.h needed? I don't see any reference here.
It compiled for me without it.

> +
>   void show_user_instructions(struct pt_regs *regs);
>   
> +static inline bool on_thread_stack(void)
> +{
> +	return !(((unsigned long)(current->stack) ^ current_stack_pointer)
> +			& ~(THREAD_SIZE -1));
> +}
> +
>   #endif /* _ASM_POWERPC_STACKTRACE_H */
> diff --git a/arch/powerpc/include/asm/syscall.h b/arch/powerpc/include/asm/syscall.h
> index 4b3c52ed6e9d2..834fcc4f7b543 100644
> --- a/arch/powerpc/include/asm/syscall.h
> +++ b/arch/powerpc/include/asm/syscall.h
> @@ -139,4 +139,9 @@ static inline int syscall_get_arch(struct task_struct *task)
>   	else
>   		return AUDIT_ARCH_PPC64;
>   }
> +
> +static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
> +{
> +	return false;
> +}
>   #endif	/* _ASM_SYSCALL_H */
> diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h
> index 2785c7462ebf7..d0e87c9bae0b0 100644
> --- a/arch/powerpc/include/asm/thread_info.h
> +++ b/arch/powerpc/include/asm/thread_info.h
> @@ -54,6 +54,7 @@
>   struct thread_info {
>   	int		preempt_count;		/* 0 => preemptable,
>   						   <0 => BUG */
> +	unsigned long	syscall_work;		/* SYSCALL_WORK_ flags */

Can this go after cpu ? it would be 8 byte aligned then. Since it is in 
fast path, might help.

>   #ifdef CONFIG_SMP
>   	unsigned int	cpu;
>   #endif
Re: [RFC V2 2/8] powerpc: Prepare to build with generic entry/exit framework
Posted by Mukesh Kumar Chaurasiya 4 months, 3 weeks ago 
On 9/13/25 6:19 PM, Shrikanth Hegde wrote:
>
>
> On 9/9/25 2:32 AM, Mukesh Kumar Chaurasiya wrote:
>> Enabling build with generic entry/exit framework for powerpc
>> architecture requires few necessary steps.
>>
>> Introducing minor infrastructure updates to prepare for future generic
>> framework handling:
>>
>> - Add syscall_work field to struct thread_info for SYSCALL_WORK_* flags.
>> - Provide arch_syscall_is_vdso_sigreturn() stub, returning false.
>> - Add on_thread_stack() helper to test whether the current stack pointer
>>    lies within the task’s kernel stack.
>>
>> No functional change is intended with this patch.
>>
>> Signed-off-by: Mukesh Kumar Chaurasiya <mchauras@linux.ibm.com>
>> ---
>>   arch/powerpc/include/asm/entry-common.h | 11 +++++++++++
>>   arch/powerpc/include/asm/stacktrace.h   |  8 ++++++++
>>   arch/powerpc/include/asm/syscall.h      |  5 +++++
>>   arch/powerpc/include/asm/thread_info.h  |  1 +
>>   4 files changed, 25 insertions(+)
>>   create mode 100644 arch/powerpc/include/asm/entry-common.h
>>
>> diff --git a/arch/powerpc/include/asm/entry-common.h 
>> b/arch/powerpc/include/asm/entry-common.h
>> new file mode 100644
>> index 0000000000000..3af16d821d07e
>> --- /dev/null
>> +++ b/arch/powerpc/include/asm/entry-common.h
>> @@ -0,0 +1,11 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +
>> +#ifndef _ASM_PPC_ENTRY_COMMON_H
>> +#define _ASM_PPC_ENTRY_COMMON_H
>> +
>> +#ifdef CONFIG_GENERIC_IRQ_ENTRY
>> +
>> +#include <asm/stacktrace.h>
>> +
>> +#endif /* CONFIG_GENERIC_IRQ_ENTRY */
>> +#endif /* _ASM_PPC_ENTRY_COMMON_H */
>> diff --git a/arch/powerpc/include/asm/stacktrace.h 
>> b/arch/powerpc/include/asm/stacktrace.h
>> index 6149b53b3bc8e..3f0a242468813 100644
>> --- a/arch/powerpc/include/asm/stacktrace.h
>> +++ b/arch/powerpc/include/asm/stacktrace.h
>> @@ -8,6 +8,14 @@
>>   #ifndef _ASM_POWERPC_STACKTRACE_H
>>   #define _ASM_POWERPC_STACKTRACE_H
>>   +#include <linux/sched.h>
>
> nit:
>
> Is sched.h needed? I don't see any reference here.
> It compiled for me without it.
>
Will remove this in next revision.
>> +
>>   void show_user_instructions(struct pt_regs *regs);
>>   +static inline bool on_thread_stack(void)
>> +{
>> +    return !(((unsigned long)(current->stack) ^ current_stack_pointer)
>> +            & ~(THREAD_SIZE -1));
>> +}
>> +
>>   #endif /* _ASM_POWERPC_STACKTRACE_H */
>> diff --git a/arch/powerpc/include/asm/syscall.h 
>> b/arch/powerpc/include/asm/syscall.h
>> index 4b3c52ed6e9d2..834fcc4f7b543 100644
>> --- a/arch/powerpc/include/asm/syscall.h
>> +++ b/arch/powerpc/include/asm/syscall.h
>> @@ -139,4 +139,9 @@ static inline int syscall_get_arch(struct 
>> task_struct *task)
>>       else
>>           return AUDIT_ARCH_PPC64;
>>   }
>> +
>> +static inline bool arch_syscall_is_vdso_sigreturn(struct pt_regs *regs)
>> +{
>> +    return false;
>> +}
>>   #endif    /* _ASM_SYSCALL_H */
>> diff --git a/arch/powerpc/include/asm/thread_info.h 
>> b/arch/powerpc/include/asm/thread_info.h
>> index 2785c7462ebf7..d0e87c9bae0b0 100644
>> --- a/arch/powerpc/include/asm/thread_info.h
>> +++ b/arch/powerpc/include/asm/thread_info.h
>> @@ -54,6 +54,7 @@
>>   struct thread_info {
>>       int        preempt_count;        /* 0 => preemptable,
>>                              <0 => BUG */
>> +    unsigned long    syscall_work;        /* SYSCALL_WORK_ flags */
>
> Can this go after cpu ? it would be 8 byte aligned then. Since it is 
> in fast path, might help.
>
Oh yeah, will move this in next revision.

Thanks,

Mukesh

>>   #ifdef CONFIG_SMP
>>       unsigned int    cpu;
>>   #endif
>

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