perf s390: add regs_query_register_offset()
The regs_query_register_offset() helper function converts
register name like "%r0" to an offset of a register in user_pt_regs
It is required by the BPF prologue generator.
The user_pt_regs structure was recently added to "asm/ptrace.h".
Hence, update tools/perf/check-headers.sh to keep the header file
in sync with kernel changes.
Suggested-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Reviewed-and-tested-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/tools/perf/arch/s390/util/dwarf-regs.c b/tools/perf/arch/s390/util/dwarf-regs.c
index f47576c..a8ace5c 100644
--- a/tools/perf/arch/s390/util/dwarf-regs.c
+++ b/tools/perf/arch/s390/util/dwarf-regs.c
@@ -2,17 +2,43 @@
/*
* Mapping of DWARF debug register numbers into register names.
*
- * Copyright IBM Corp. 2010
- * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ * Copyright IBM Corp. 2010, 2017
+ * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>,
+ * Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
*
*/
+#include <errno.h>
#include <stddef.h>
-#include <dwarf-regs.h>
+#include <stdlib.h>
#include <linux/kernel.h>
+#include <asm/ptrace.h>
+#include <string.h>
+#include <dwarf-regs.h>
#include "dwarf-regs-table.h"
const char *get_arch_regstr(unsigned int n)
{
return (n >= ARRAY_SIZE(s390_dwarf_regs)) ? NULL : s390_dwarf_regs[n];
}
+
+/*
+ * Convert the register name into an offset to struct pt_regs (kernel).
+ * This is required by the BPF prologue generator. The BPF
+ * program is called in the BPF overflow handler in the perf
+ * core.
+ */
+int regs_query_register_offset(const char *name)
+{
+ unsigned long gpr;
+
+ if (!name || strncmp(name, "%r", 2))
+ return -EINVAL;
+
+ errno = 0;
+ gpr = strtoul(name + 2, NULL, 10);
+ if (errno || gpr >= 16)
+ return -EINVAL;
+
+ return offsetof(user_pt_regs, gprs) + 8 * gpr;
+}