[RFC PATCH v2 03/15] perf bpf: Save pt_regs info from debuginfo

From: He Kuang
Date: Sun May 24 2015 - 04:30:16 EST


Save reg number in function convert_variable_location() instead of the
register string name, so we can fetch the target register from bpf
context register later.

Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
---
tools/perf/util/include/dwarf-regs.h | 13 +++++++++++++
tools/perf/util/probe-event.h | 1 +
tools/perf/util/probe-finder.c | 11 +++++++++++
3 files changed, 25 insertions(+)

diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
index 8f14965..566ff6d 100644
--- a/tools/perf/util/include/dwarf-regs.h
+++ b/tools/perf/util/include/dwarf-regs.h
@@ -2,7 +2,20 @@
#define _PERF_DWARF_REGS_H_

#ifdef HAVE_DWARF_SUPPORT
+struct arch_regs_info {
+ const char *name; /* Architecture dependent register string */
+ int offset; /* Reg offset in struct pt_regs */
+ int size; /* Reg size */
+};
+
+#define ARCH_REGS_INFO(r, pt_reg_name) \
+ {.name = r, \
+ .offset = offsetof(struct pt_regs, pt_reg_name), \
+ .size = sizeof(((struct pt_regs *)0)->pt_reg_name)} \
+
const char *get_arch_regstr(unsigned int n);
+int get_arch_reg_offset(unsigned int n);
+int get_arch_reg_size(unsigned int n);
#endif

#endif
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index d6b7834..6c19395 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -29,6 +29,7 @@ struct probe_trace_arg {
char *value; /* Base value */
char *type; /* Type name */
struct probe_trace_arg_ref *ref; /* Referencing offset */
+ unsigned int regn; /* Regn from dwarf */
};

/* kprobe-tracer and uprobe-tracer tracing event (point + arg) */
diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
index ee27b74..681af00 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -159,6 +159,16 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
return ref;
}

+int __attribute__ ((weak))
+get_arch_reg_offset(unsigned int n __maybe_unused) {
+ return -1;
+}
+
+int __attribute__ ((weak))
+get_arch_reg_size(unsigned int n __maybe_unused) {
+ return -1;
+}
+
/*
* Convert a location into trace_arg.
* If tvar == NULL, this just checks variable can be converted.
@@ -260,6 +270,7 @@ static_var:
return -ERANGE;
}

+ tvar->regn = regn;
tvar->value = strdup(regs);
if (tvar->value == NULL)
return -ENOMEM;
--
1.8.5.2

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