* @file backtrace.c
*
* @remark Copyright 2008 Tensilica Inc.
+ * Copyright (C) 2015 Cadence Design Systems Inc.
* @remark Read the file COPYING
*
*/
#include <linux/oprofile.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
#include <asm/ptrace.h>
-#include <asm/uaccess.h>
-#include <asm/traps.h>
+#include <asm/stacktrace.h>
-/* Address of common_exception_return, used to check the
- * transition from kernel to user space.
- */
-extern int common_exception_return;
-
-/* A struct that maps to the part of the frame containing the a0 and
- * a1 registers.
- */
-struct frame_start {
- unsigned long a0;
- unsigned long a1;
-};
-
-static void xtensa_backtrace_user(struct pt_regs *regs, unsigned int depth)
-{
- unsigned long windowstart = regs->windowstart;
- unsigned long windowbase = regs->windowbase;
- unsigned long a0 = regs->areg[0];
- unsigned long a1 = regs->areg[1];
- unsigned long pc = MAKE_PC_FROM_RA(a0, regs->pc);
- int index;
-
- /* First add the current PC to the trace. */
- if (pc != 0 && pc <= TASK_SIZE)
- oprofile_add_trace(pc);
- else
- return;
-
- /* Two steps:
- *
- * 1. Look through the register window for the
- * previous PCs in the call trace.
- *
- * 2. Look on the stack.
- */
-
- /* Step 1. */
- /* Rotate WINDOWSTART to move the bit corresponding to
- * the current window to the bit #0.
- */
- windowstart = (windowstart << WSBITS | windowstart) >> windowbase;
-
- /* Look for bits that are set, they correspond to
- * valid windows.
- */
- for (index = WSBITS - 1; (index > 0) && depth; depth--, index--)
- if (windowstart & (1 << index)) {
- /* Read a0 and a1 from the
- * corresponding position in AREGs.
- */
- a0 = regs->areg[index * 4];
- a1 = regs->areg[index * 4 + 1];
- /* Get the PC from a0 and a1. */
- pc = MAKE_PC_FROM_RA(a0, pc);
-
- /* Add the PC to the trace. */
- if (pc != 0 && pc <= TASK_SIZE)
- oprofile_add_trace(pc);
- else
- return;
- }
-
- /* Step 2. */
- /* We are done with the register window, we need to
- * look through the stack.
- */
- if (depth > 0) {
- /* Start from the a1 register. */
- /* a1 = regs->areg[1]; */
- while (a0 != 0 && depth--) {
-
- struct frame_start frame_start;
- /* Get the location for a1, a0 for the
- * previous frame from the current a1.
- */
- unsigned long *psp = (unsigned long *)a1;
- psp -= 4;
-
- /* Check if the region is OK to access. */
- if (!access_ok(VERIFY_READ, psp, sizeof(frame_start)))
- return;
- /* Copy a1, a0 from user space stack frame. */
- if (__copy_from_user_inatomic(&frame_start, psp,
- sizeof(frame_start)))
- return;
-
- a0 = frame_start.a0;
- a1 = frame_start.a1;
- pc = MAKE_PC_FROM_RA(a0, pc);
-
- if (pc != 0 && pc <= TASK_SIZE)
- oprofile_add_trace(pc);
- else
- return;
- }
- }
-}
-
-static void xtensa_backtrace_kernel(struct pt_regs *regs, unsigned int depth)
+static int xtensa_backtrace_cb(struct stackframe *frame, void *data)
{
- unsigned long pc = regs->pc;
- unsigned long *psp;
- unsigned long sp_start, sp_end;
- unsigned long a0 = regs->areg[0];
- unsigned long a1 = regs->areg[1];
-
- sp_start = a1 & ~(THREAD_SIZE-1);
- sp_end = sp_start + THREAD_SIZE;
-
- /* Spill the register window to the stack first. */
- spill_registers();
-
- /* Read the stack frames one by one and create the PC
- * from the a0 and a1 registers saved there.
- */
- while (a1 > sp_start && a1 < sp_end && depth--) {
- pc = MAKE_PC_FROM_RA(a0, pc);
-
- /* Add the PC to the trace. */
- oprofile_add_trace(pc);
- if (pc == (unsigned long) &common_exception_return) {
- regs = (struct pt_regs *)a1;
- if (user_mode(regs)) {
- pc = regs->pc;
- if (pc != 0 && pc <= TASK_SIZE)
- oprofile_add_trace(pc);
- else
- return;
- return xtensa_backtrace_user(regs, depth);
- }
- a0 = regs->areg[0];
- a1 = regs->areg[1];
- continue;
- }
-
- psp = (unsigned long *)a1;
-
- a0 = *(psp - 4);
- a1 = *(psp - 3);
-
- if (a1 <= (unsigned long)psp)
- return;
-
- }
- return;
+ oprofile_add_trace(frame->pc);
+ return 0;
}
void xtensa_backtrace(struct pt_regs * const regs, unsigned int depth)
{
if (user_mode(regs))
- xtensa_backtrace_user(regs, depth);
+ xtensa_backtrace_user(regs, depth, xtensa_backtrace_cb, NULL);
else
- xtensa_backtrace_kernel(regs, depth);
+ xtensa_backtrace_kernel(regs, depth, xtensa_backtrace_cb,
+ xtensa_backtrace_cb, NULL);
}
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