Re: [PATCH] stacktrace: Move documentation for arch_stack_walk_reliable() to header

[Randy Dunlap <rdunlap@infradead.org>]

On 3/9/21 11:41 AM, Mark Brown wrote:
> Currently arch_stack_wallk_reliable() is documented with an identical
> comment in both x86 and S/390 implementations which is a bit redundant.
> Move this to the header and convert to kerneldoc while we're at it.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: Petr Mladek <pmladek@suse.com>
> Cc: Joe Lawrence <joe.lawrence@redhat.com>
> Cc: x86@kernel.org
> Cc: linux-s390@vger.kernel.org
> Cc: live-patching@vger.kernel.org
> Signed-off-by: Mark Brown <broonie@kernel.org>
> Acked-by: Vasily Gorbik <gor@linux.ibm.com>
> Reviewed-by: Miroslav Benes <mbenes@suse.cz>

Acked-by: Randy Dunlap <rdunlap@infradead.org>

Looks good. Thanks.

> ---
>  arch/s390/kernel/stacktrace.c |  6 ------
>  arch/x86/kernel/stacktrace.c  |  6 ------
>  include/linux/stacktrace.h    | 19 +++++++++++++++++++
>  3 files changed, 19 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/s390/kernel/stacktrace.c b/arch/s390/kernel/stacktrace.c
> index 7f1266c24f6b..101477b3e263 100644
> --- a/arch/s390/kernel/stacktrace.c
> +++ b/arch/s390/kernel/stacktrace.c
> @@ -24,12 +24,6 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
>  	}
>  }
>  
> -/*
> - * This function returns an error if it detects any unreliable features of the
> - * stack.  Otherwise it guarantees that the stack trace is reliable.
> - *
> - * If the task is not 'current', the caller *must* ensure the task is inactive.
> - */
>  int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
>  			     void *cookie, struct task_struct *task)
>  {
> diff --git a/arch/x86/kernel/stacktrace.c b/arch/x86/kernel/stacktrace.c
> index 8627fda8d993..15b058eefc4e 100644
> --- a/arch/x86/kernel/stacktrace.c
> +++ b/arch/x86/kernel/stacktrace.c
> @@ -29,12 +29,6 @@ void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
>  	}
>  }
>  
> -/*
> - * This function returns an error if it detects any unreliable features of the
> - * stack.  Otherwise it guarantees that the stack trace is reliable.
> - *
> - * If the task is not 'current', the caller *must* ensure the task is inactive.
> - */
>  int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
>  			     void *cookie, struct task_struct *task)
>  {
> diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
> index 50e2df30b0aa..9edecb494e9e 100644
> --- a/include/linux/stacktrace.h
> +++ b/include/linux/stacktrace.h
> @@ -52,8 +52,27 @@ typedef bool (*stack_trace_consume_fn)(void *cookie, unsigned long addr);
>   */
>  void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
>  		     struct task_struct *task, struct pt_regs *regs);
> +
> +/**
> + * arch_stack_walk_reliable - Architecture specific function to walk the
> + *			      stack reliably
> + *
> + * @consume_entry:	Callback which is invoked by the architecture code for
> + *			each entry.
> + * @cookie:		Caller supplied pointer which is handed back to
> + *			@consume_entry
> + * @task:		Pointer to a task struct, can be NULL
> + *
> + * This function returns an error if it detects any unreliable
> + * features of the stack. Otherwise it guarantees that the stack
> + * trace is reliable.
> + *
> + * If the task is not 'current', the caller *must* ensure the task is
> + * inactive and its stack is pinned.
> + */
>  int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry, void *cookie,
>  			     struct task_struct *task);
> +
>  void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
>  			  const struct pt_regs *regs);
>  
> 


-- 
~Randy