[tip: x86/cleanups] stacktrace: Move documentation for arch_stack_walk_reliable() to header

["tip-bot2 for Mark Brown" <tip-bot2@linutronix.de>]

The following commit has been merged into the x86/cleanups branch of tip:

Commit-ID:     b18adee4ce4443399963826b5d28d9e63d40740c
Gitweb:        https://git.kernel.org/tip/b18adee4ce4443399963826b5d28d9e63d40740c
Author:        Mark Brown <broonie@kernel.org>
AuthorDate:    Tue, 09 Mar 2021 19:41:25 
Committer:     Borislav Petkov <bp@suse.de>
CommitterDate: Wed, 10 Mar 2021 15:52:31 +01:00

stacktrace: Move documentation for arch_stack_walk_reliable() to header

Currently arch_stack_walk_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.

Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Vasily Gorbik <gor@linux.ibm.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Link: https://lkml.kernel.org/r/20210309194125.652-1-broonie@kernel.org
---
 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 7f1266c..101477b 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 8627fda..15b058e 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 50e2df3..9edecb4 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);