ecea4ab6d3
Many of the core ARM kernel files are not modules, but just including module.h for exporting symbols. Now these files can use the lighter footprint export.h for this role. There are probably lots more, but ARM files of mach-* and plat-* don't get coverage via a simple yesconfig build. They will have to be cleaned up and tested via using their respective configs. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
132 lines
3.3 KiB
C
132 lines
3.3 KiB
C
#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include <asm/stacktrace.h>
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#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)
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/*
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* Unwind the current stack frame and store the new register values in the
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* structure passed as argument. Unwinding is equivalent to a function return,
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* hence the new PC value rather than LR should be used for backtrace.
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*
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* With framepointer enabled, a simple function prologue looks like this:
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* mov ip, sp
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* stmdb sp!, {fp, ip, lr, pc}
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* sub fp, ip, #4
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*
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* A simple function epilogue looks like this:
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* ldm sp, {fp, sp, pc}
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*
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* Note that with framepointer enabled, even the leaf functions have the same
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* prologue and epilogue, therefore we can ignore the LR value in this case.
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*/
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int notrace unwind_frame(struct stackframe *frame)
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{
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unsigned long high, low;
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unsigned long fp = frame->fp;
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/* only go to a higher address on the stack */
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low = frame->sp;
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high = ALIGN(low, THREAD_SIZE);
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/* check current frame pointer is within bounds */
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if (fp < (low + 12) || fp + 4 >= high)
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return -EINVAL;
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/* restore the registers from the stack frame */
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frame->fp = *(unsigned long *)(fp - 12);
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frame->sp = *(unsigned long *)(fp - 8);
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frame->pc = *(unsigned long *)(fp - 4);
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return 0;
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}
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#endif
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void notrace walk_stackframe(struct stackframe *frame,
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int (*fn)(struct stackframe *, void *), void *data)
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{
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while (1) {
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int ret;
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if (fn(frame, data))
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break;
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ret = unwind_frame(frame);
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if (ret < 0)
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break;
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}
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}
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EXPORT_SYMBOL(walk_stackframe);
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#ifdef CONFIG_STACKTRACE
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struct stack_trace_data {
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struct stack_trace *trace;
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unsigned int no_sched_functions;
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unsigned int skip;
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};
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static int save_trace(struct stackframe *frame, void *d)
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{
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struct stack_trace_data *data = d;
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struct stack_trace *trace = data->trace;
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unsigned long addr = frame->pc;
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if (data->no_sched_functions && in_sched_functions(addr))
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return 0;
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if (data->skip) {
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data->skip--;
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return 0;
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}
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trace->entries[trace->nr_entries++] = addr;
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return trace->nr_entries >= trace->max_entries;
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}
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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{
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struct stack_trace_data data;
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struct stackframe frame;
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data.trace = trace;
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data.skip = trace->skip;
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if (tsk != current) {
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#ifdef CONFIG_SMP
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/*
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* What guarantees do we have here that 'tsk' is not
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* running on another CPU? For now, ignore it as we
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* can't guarantee we won't explode.
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*/
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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return;
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#else
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data.no_sched_functions = 1;
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frame.fp = thread_saved_fp(tsk);
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frame.sp = thread_saved_sp(tsk);
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frame.lr = 0; /* recovered from the stack */
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frame.pc = thread_saved_pc(tsk);
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#endif
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} else {
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register unsigned long current_sp asm ("sp");
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data.no_sched_functions = 0;
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frame.fp = (unsigned long)__builtin_frame_address(0);
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frame.sp = current_sp;
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frame.lr = (unsigned long)__builtin_return_address(0);
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frame.pc = (unsigned long)save_stack_trace_tsk;
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}
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walk_stackframe(&frame, save_trace, &data);
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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}
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void save_stack_trace(struct stack_trace *trace)
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{
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save_stack_trace_tsk(current, trace);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace);
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#endif
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