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Linux/arch/arm/oprofile/common.c

  1 /**
  2  * @file common.c
  3  *
  4  * @remark Copyright 2004 Oprofile Authors
  5  * @remark Copyright 2010 ARM Ltd.
  6  * @remark Read the file COPYING
  7  *
  8  * @author Zwane Mwaikambo
  9  * @author Will Deacon [move to perf]
 10  */
 11 
 12 #include <linux/cpumask.h>
 13 #include <linux/init.h>
 14 #include <linux/mutex.h>
 15 #include <linux/oprofile.h>
 16 #include <linux/perf_event.h>
 17 #include <linux/platform_device.h>
 18 #include <linux/slab.h>
 19 #include <asm/stacktrace.h>
 20 #include <linux/uaccess.h>
 21 
 22 #include <asm/perf_event.h>
 23 #include <asm/ptrace.h>
 24 
 25 #ifdef CONFIG_HW_PERF_EVENTS
 26 
 27 /*
 28  * OProfile has a curious naming scheme for the ARM PMUs, but they are
 29  * part of the user ABI so we need to map from the perf PMU name for
 30  * supported PMUs.
 31  */
 32 static struct op_perf_name {
 33         char *perf_name;
 34         char *op_name;
 35 } op_perf_name_map[] = {
 36         { "xscale1",            "arm/xscale1"   },
 37         { "xscale1",            "arm/xscale2"   },
 38         { "v6",                 "arm/armv6"     },
 39         { "v6mpcore",           "arm/mpcore"    },
 40         { "ARMv7 Cortex-A8",    "arm/armv7"     },
 41         { "ARMv7 Cortex-A9",    "arm/armv7-ca9" },
 42 };
 43 
 44 char *op_name_from_perf_id(void)
 45 {
 46         int i;
 47         struct op_perf_name names;
 48         const char *perf_name = perf_pmu_name();
 49 
 50         for (i = 0; i < ARRAY_SIZE(op_perf_name_map); ++i) {
 51                 names = op_perf_name_map[i];
 52                 if (!strcmp(names.perf_name, perf_name))
 53                         return names.op_name;
 54         }
 55 
 56         return NULL;
 57 }
 58 #endif
 59 
 60 static int report_trace(struct stackframe *frame, void *d)
 61 {
 62         unsigned int *depth = d;
 63 
 64         if (*depth) {
 65                 oprofile_add_trace(frame->pc);
 66                 (*depth)--;
 67         }
 68 
 69         return *depth == 0;
 70 }
 71 
 72 /*
 73  * The registers we're interested in are at the end of the variable
 74  * length saved register structure. The fp points at the end of this
 75  * structure so the address of this struct is:
 76  * (struct frame_tail *)(xxx->fp)-1
 77  */
 78 struct frame_tail {
 79         struct frame_tail *fp;
 80         unsigned long sp;
 81         unsigned long lr;
 82 } __attribute__((packed));
 83 
 84 static struct frame_tail* user_backtrace(struct frame_tail *tail)
 85 {
 86         struct frame_tail buftail[2];
 87 
 88         /* Also check accessibility of one struct frame_tail beyond */
 89         if (!access_ok(VERIFY_READ, tail, sizeof(buftail)))
 90                 return NULL;
 91         if (__copy_from_user_inatomic(buftail, tail, sizeof(buftail)))
 92                 return NULL;
 93 
 94         oprofile_add_trace(buftail[0].lr);
 95 
 96         /* frame pointers should strictly progress back up the stack
 97          * (towards higher addresses) */
 98         if (tail + 1 >= buftail[0].fp)
 99                 return NULL;
100 
101         return buftail[0].fp-1;
102 }
103 
104 static void arm_backtrace(struct pt_regs * const regs, unsigned int depth)
105 {
106         struct frame_tail *tail = ((struct frame_tail *) regs->ARM_fp) - 1;
107 
108         if (!user_mode(regs)) {
109                 struct stackframe frame;
110                 frame.fp = regs->ARM_fp;
111                 frame.sp = regs->ARM_sp;
112                 frame.lr = regs->ARM_lr;
113                 frame.pc = regs->ARM_pc;
114                 walk_stackframe(&frame, report_trace, &depth);
115                 return;
116         }
117 
118         while (depth-- && tail && !((unsigned long) tail & 3))
119                 tail = user_backtrace(tail);
120 }
121 
122 int __init oprofile_arch_init(struct oprofile_operations *ops)
123 {
124         /* provide backtrace support also in timer mode: */
125         ops->backtrace          = arm_backtrace;
126 
127         return oprofile_perf_init(ops);
128 }
129 
130 void oprofile_arch_exit(void)
131 {
132         oprofile_perf_exit();
133 }
134 

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