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kernel/linux-imx6_3.14.28/arch/arm/oprofile/common.c 2.96 KB
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  /**
   * @file common.c
   *
   * @remark Copyright 2004 Oprofile Authors
   * @remark Copyright 2010 ARM Ltd.
   * @remark Read the file COPYING
   *
   * @author Zwane Mwaikambo
   * @author Will Deacon [move to perf]
   */
  
  #include <linux/cpumask.h>
  #include <linux/init.h>
  #include <linux/mutex.h>
  #include <linux/oprofile.h>
  #include <linux/perf_event.h>
  #include <linux/platform_device.h>
  #include <linux/slab.h>
  #include <asm/stacktrace.h>
  #include <linux/uaccess.h>
  
  #include <asm/perf_event.h>
  #include <asm/ptrace.h>
  
  #ifdef CONFIG_HW_PERF_EVENTS
  
  /*
   * OProfile has a curious naming scheme for the ARM PMUs, but they are
   * part of the user ABI so we need to map from the perf PMU name for
   * supported PMUs.
   */
  static struct op_perf_name {
  	char *perf_name;
  	char *op_name;
  } op_perf_name_map[] = {
  	{ "xscale1",		"arm/xscale1"	},
  	{ "xscale1",		"arm/xscale2"	},
  	{ "v6",			"arm/armv6"	},
  	{ "v6mpcore",		"arm/mpcore"	},
  	{ "ARMv7 Cortex-A8",	"arm/armv7"	},
  	{ "ARMv7 Cortex-A9",	"arm/armv7-ca9"	},
  };
  
  char *op_name_from_perf_id(void)
  {
  	int i;
  	struct op_perf_name names;
  	const char *perf_name = perf_pmu_name();
  
  	for (i = 0; i < ARRAY_SIZE(op_perf_name_map); ++i) {
  		names = op_perf_name_map[i];
  		if (!strcmp(names.perf_name, perf_name))
  			return names.op_name;
  	}
  
  	return NULL;
  }
  #endif
  
  static int report_trace(struct stackframe *frame, void *d)
  {
  	unsigned int *depth = d;
  
  	if (*depth) {
  		oprofile_add_trace(frame->pc);
  		(*depth)--;
  	}
  
  	return *depth == 0;
  }
  
  /*
   * The registers we're interested in are at the end of the variable
   * length saved register structure. The fp points at the end of this
   * structure so the address of this struct is:
   * (struct frame_tail *)(xxx->fp)-1
   */
  struct frame_tail {
  	struct frame_tail *fp;
  	unsigned long sp;
  	unsigned long lr;
  } __attribute__((packed));
  
  static struct frame_tail* user_backtrace(struct frame_tail *tail)
  {
  	struct frame_tail buftail[2];
  
  	/* Also check accessibility of one struct frame_tail beyond */
  	if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
  		return NULL;
  	if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
  		return NULL;
  
  	oprofile_add_trace(buftail[0].lr);
  
  	/* frame pointers should strictly progress back up the stack
  	 * (towards higher addresses) */
  	if (tail + 1 >= buftail[0].fp)
  		return NULL;
  
  	return buftail[0].fp-1;
  }
  
  static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
  {
  	struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
  
  	if (!user_mode(regs)) {
  		struct stackframe frame;
  		frame.fp = regs->ARM_fp;
  		frame.sp = regs->ARM_sp;
  		frame.lr = regs->ARM_lr;
  		frame.pc = regs->ARM_pc;
  		walk_stackframe(&frame, report_trace, &depth);
  		return;
  	}
  
  	while (depth-- && tail && !((unsigned long) tail & 3))
  		tail = user_backtrace(tail);
  }
  
  int __init oprofile_arch_init(struct oprofile_operations *ops)
  {
  	/* provide backtrace support also in timer mode: */
  	ops->backtrace		= arm_backtrace;
  
  	return oprofile_perf_init(ops);
  }
  
  void oprofile_arch_exit(void)
  {
  	oprofile_perf_exit();
  }