[RFC PATCH 3/6] perf bpf: Save pt_regs info from debuginfo

From: He Kuang
Date: Tue May 05 2015 - 06:11:50 EST


Save pt_regs number and size information 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 | 2 ++
tools/perf/util/probe-event.h | 4 ++++
tools/perf/util/probe-finder.c | 11 +++++++++++
3 files changed, 17 insertions(+)

diff --git a/tools/perf/util/include/dwarf-regs.h b/tools/perf/util/include/dwarf-regs.h
index 8f14965..166bec2 100644
--- a/tools/perf/util/include/dwarf-regs.h
+++ b/tools/perf/util/include/dwarf-regs.h
@@ -3,6 +3,8 @@

#ifdef HAVE_DWARF_SUPPORT
const char *get_arch_regstr(unsigned int n);
+char get_arch_pt_regs(unsigned int n);
+int get_arch_pt_regs_size(void);
#endif

#endif
diff --git a/tools/perf/util/probe-event.h b/tools/perf/util/probe-event.h
index d6b7834..842d6c4 100644
--- a/tools/perf/util/probe-event.h
+++ b/tools/perf/util/probe-event.h
@@ -29,6 +29,10 @@ struct probe_trace_arg {
char *value; /* Base value */
char *type; /* Type name */
struct probe_trace_arg_ref *ref; /* Referencing offset */
+ unsigned int regn;
+ unsigned int reg_size;
+ char *insns;
+ int insns_cnt;
};

/* 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 2a76e14..249e6cb 100644
--- a/tools/perf/util/probe-finder.c
+++ b/tools/perf/util/probe-finder.c
@@ -159,6 +159,15 @@ static struct probe_trace_arg_ref *alloc_trace_arg_ref(long offs)
return ref;
}

+char __attribute__ ((weak)) get_arch_pt_regs(unsigned int n) {
+ n = n;
+ return -1;
+}
+
+int __attribute__ ((weak)) get_arch_pt_regs_size(void) {
+ return -1;
+}
+
/*
* Convert a location into trace_arg.
* If tvar == NULL, this just checks variable can be converted.
@@ -260,6 +269,8 @@ static_var:
return -ERANGE;
}

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

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