[RFC v4 8/9] Link frame_info to thread_info

Philipp Rudo
2017-06-12T17:08:54Z

Linux kernel stacks on S390 are spread over several memory locations.
These locations differ for every kernel task/thread. Thus we need to know
to which task/thread a frame belongs to check whether a stack pointer is
valid and when to stop unwinding. To do so add a pointer to corresponding
thread_info to frame_info.

This connection already exists implicitly by the fact that switch_to_thread
reinitializes the frame cache.

gdb/ChangeLog:

* frame.h (frame_get_thread): New extern declaration.
* frame.c (frame_info) <thread>: New field.
(frame_get_thread): New function.
(create_sentinel_frame, create_new_frame, get_prev_frame_raw): Set
new field.
---
gdb/frame.c | 12 ++++++++++++
gdb/frame.h | 2 ++
2 files changed, 14 insertions(+)

diff --git a/gdb/frame.c b/gdb/frame.c
index 30e4aeab7e..5a2fdda783 100644
--- a/gdb/frame.c
+++ b/gdb/frame.c
@@ -101,6 +101,9 @@ struct frame_info
/* The frame's address space. */
struct address_space *aspace;

+ /* The thread this frame belongs to. */
+ struct thread_info *thread;
+
/* The frame's low-level unwinder and corresponding cache. The
low-level unwinder is responsible for unwinding register values
for the previous frame. The low-level unwind methods are
@@ -157,6 +160,12 @@ struct frame_info
const char *stop_string;
};

+struct thread_info *
+frame_get_thread (struct frame_info *frame)
+{
+ return frame->thread;
+}
+
/* A frame stash used to speed up frame lookups. Create a hash table
to stash frames previously accessed from the frame cache for
quicker subsequent retrieval. The hash table is emptied whenever
@@ -1527,6 +1536,7 @@ create_sentinel_frame (struct program_space *pspace, struct regcache *regcache)
frame->level = -1;
frame->pspace = pspace;
frame->aspace = get_regcache_aspace (regcache);
+ frame->thread = inferior_thread ();
/* Explicitly initialize the sentinel frame's cache. Provide it
with the underlying regcache. In the future additional
information, such as the frame's thread will be added. */
@@ -1768,6 +1778,7 @@ create_new_frame (CORE_ADDR addr, CORE_ADDR pc)
/* We currently assume that frame chain's can't cross spaces. */
fi->pspace = fi->next->pspace;
fi->aspace = fi->next->aspace;
+ fi->thread = fi->next->thread;

/* Select/initialize both the unwind function and the frame's type
based on the PC. */
@@ -2179,6 +2190,7 @@ get_prev_frame_raw (struct frame_info *this_frame)
spaces. */
prev_frame->pspace = this_frame->pspace;
prev_frame->aspace = this_frame->aspace;
+ prev_frame->thread = this_frame->thread;

/* Don't yet compute ->unwind (and hence ->type). It is computed
on-demand in get_frame_type, frame_register_unwind, and
diff --git a/gdb/frame.h b/gdb/frame.h
index 56cbd4400b..26079e8215 100644
--- a/gdb/frame.h
+++ b/gdb/frame.h
@@ -103,6 +103,8 @@ enum frame_id_stack_status

struct frame_info;

+extern struct thread_info *frame_get_thread (struct frame_info *frame);
+
/* The frame object's ID. This provides a per-frame unique identifier
that can be used to relocate a `struct frame_info' after a target
resume or a frame cache destruct. It of course assumes that the
--
2.11.2