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author | Steven Rostedt <srostedt@redhat.com> | 2014-02-06 09:41:30 -0500 |
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committer | H. Peter Anvin <hpa@linux.intel.com> | 2014-03-06 16:56:54 -0800 |
commit | 0788aa6a23cb9d693fc5040ec774b979f1e906cd (patch) | |
tree | b1c5fd2dab9c0e11bc1747e5f6102d89d16dfcc0 /arch/x86/kernel/dumpstack_32.c | |
parent | b807902a88c470eb06d0acdf3b6590f27f5dce81 (diff) | |
download | linux-stable-0788aa6a23cb9d693fc5040ec774b979f1e906cd.tar.gz linux-stable-0788aa6a23cb9d693fc5040ec774b979f1e906cd.tar.bz2 linux-stable-0788aa6a23cb9d693fc5040ec774b979f1e906cd.zip |
x86: Prepare removal of previous_esp from i386 thread_info structure
The i386 thread_info contains a previous_esp field that is used
to daisy chain the different stacks for dump_stack()
(ie. irq, softirq, thread stacks).
The goal is to eventual make i386 handling of thread_info the same
as x86_64, which means that the thread_info will not be in the stack
but as a per_cpu variable. We will no longer depend on thread_info
being able to daisy chain different stacks as it will only exist
in one location (the thread stack).
By moving previous_esp to the end of thread_info and referencing
it as an offset instead of using a thread_info field, this becomes
a stepping stone to moving the thread_info.
The offset to get to the previous stack is rather ugly in this
patch, but this is only temporary and the prev_esp will be changed
in the next commit. This commit is more for sanity checks of the
change.
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Robert Richter <rric@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20110806012353.891757693@goodmis.org
Link: http://lkml.kernel.org/r/20140206144321.608754481@goodmis.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/kernel/dumpstack_32.c')
-rw-r--r-- | arch/x86/kernel/dumpstack_32.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index f2a1770ca176..187d6a749c19 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -22,6 +22,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, const struct stacktrace_ops *ops, void *data) { int graph = 0; + u32 *prev_esp; if (!task) task = current; @@ -44,9 +45,17 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs, ((unsigned long)stack & (~(THREAD_SIZE - 1))); bp = ops->walk_stack(context, stack, bp, ops, data, NULL, &graph); - stack = (unsigned long *)context->previous_esp; + /* Stop if not on irq stack */ + if (task_stack_page(task) == context) + break; + + /* The previous esp is just above the context */ + prev_esp = (u32 *) ((char *)context + sizeof(struct thread_info) - + sizeof(long)); + stack = (unsigned long *)*prev_esp; if (!stack) break; + if (ops->stack(data, "IRQ") < 0) break; touch_nmi_watchdog(); |