[PATCH v2 2/3] perf tools: Enable bpf prologue for arm64

From: He Kuang
Date: Fri Feb 03 2017 - 06:06:35 EST


Since HAVE_KPROBES can be enabled in arm64, this patch introduces
regs_query_register_offset() to convert register name to offset for
arm64, so the BPF prologue feature is ready to use.

Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
---
tools/perf/arch/arm64/Makefile | 1 +
tools/perf/arch/arm64/util/dwarf-regs.c | 20 ++++++++++++++++++++
2 files changed, 21 insertions(+)

diff --git a/tools/perf/arch/arm64/Makefile b/tools/perf/arch/arm64/Makefile
index 18b1351..eebe1ec 100644
--- a/tools/perf/arch/arm64/Makefile
+++ b/tools/perf/arch/arm64/Makefile
@@ -2,3 +2,4 @@ ifndef NO_DWARF
PERF_HAVE_DWARF_REGS := 1
endif
PERF_HAVE_JITDUMP := 1
+PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
diff --git a/tools/perf/arch/arm64/util/dwarf-regs.c b/tools/perf/arch/arm64/util/dwarf-regs.c
index 090f36b..6d17a31 100644
--- a/tools/perf/arch/arm64/util/dwarf-regs.c
+++ b/tools/perf/arch/arm64/util/dwarf-regs.c
@@ -9,6 +9,8 @@
*/

#include <stddef.h>
+#include <errno.h> /* for EINVAL */
+#include <string.h> /* for strcmp */
#include <linux/ptrace.h> /* for struct user_pt_regs */
#include <dwarf-regs.h>

@@ -75,3 +77,21 @@ const char *get_arch_regstr(unsigned int n)
{
return (n < ARCH_MAX_REGS) ? regoffset_table[n].name : NULL;
}
+
+/* Reuse code from arch/arm64/kernel/ptrace.c */
+/**
+ * regs_query_register_offset() - query register offset from its name
+ * @name: the name of a register
+ *
+ * regs_query_register_offset() returns the offset of a register in struct
+ * user_pt_regs from its name. If the name is invalid, this returns -EINVAL;
+ */
+int regs_query_register_offset(const char *name)
+{
+ const struct pt_regs_offset *roff;
+
+ for (roff = regoffset_table; roff->name != NULL; roff++)
+ if (!strcmp(roff->name, name))
+ return roff->offset;
+ return -EINVAL;
+}
--
1.8.5.2