perf: Unified API to record selective sets of arch registers

This brings a new API to help the selective dump of registers on event
sampling, and its implementation for x86 arch.

Added HAVE_PERF_REGS config option to determine if the architecture
provides perf registers ABI.

The information about desired registers will be passed in u64 mask.
It's up to the architecture to map the registers into the mask bits.

For the x86 arch implementation, both 32 and 64 bit registers bits are
defined within single enum to ensure 64 bit system can provide register
dump for compat task if needed in the future.

Original-patch-by: Frederic Weisbecker <fweisbec@gmail.com>
[ Added missing linux/errno.h include ]
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: "Frank Ch. Eigler" <fche@redhat.com>
Cc: Arun Sharma <asharma@fb.com>
Cc: Benjamin Redelings <benjamin.redelings@nescent.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Ulrich Drepper <drepper@gmail.com>
Link: http://lkml.kernel.org/r/1344345647-11536-2-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/include/linux/perf_regs.h b/include/linux/perf_regs.h
new file mode 100644
index 000000000000..a2f1a98f7839
--- /dev/null
+++ b/include/linux/perf_regs.h
@@ -0,0 +1,19 @@
+#ifndef _LINUX_PERF_REGS_H
+#define _LINUX_PERF_REGS_H
+
+#ifdef CONFIG_HAVE_PERF_REGS
+#include <asm/perf_regs.h>
+u64 perf_reg_value(struct pt_regs *regs, int idx);
+int perf_reg_validate(u64 mask);
+#else
+static inline u64 perf_reg_value(struct pt_regs *regs, int idx)
+{
+	return 0;
+}
+
+static inline int perf_reg_validate(u64 mask)
+{
+	return mask ? -ENOSYS : 0;
+}
+#endif /* CONFIG_HAVE_PERF_REGS */
+#endif /* _LINUX_PERF_REGS_H */