Patch "perf jit: Enable jitdump support without dwarf" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

perf jit: Enable jitdump support without dwarf

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-jit-enable-jitdump-support-without-dwarf.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Maciej Debski <[email protected]>
Date: Thu, 13 Oct 2016 03:59:36 -0700
Subject: perf jit: Enable jitdump support without dwarf

From: Maciej Debski <[email protected]>

commit 621cb4e7837e39d25a5af5a785ad282cdd2b4ce8 upstream.

This patch modifies the build dependencies on the jitdump support in perf. As it stands jitdump was wrongfully made dependent 100% on using DWARF. However, the dwarf dependency, only exist if generating the source line table in genelf_debug.c. The rest of the support does not need DWARF.

This patch removes the dependency on DWARF for the entire jitdump support. It keeps it only for the genelf_debug.c support.

---
 tools/perf/Makefile.config |    2 +-
 tools/perf/util/Build      |    2 +-
 tools/perf/util/genelf.c   |    9 +++++++--
 tools/perf/util/genelf.h   |    2 ++
 4 files changed, 11 insertions(+), 4 deletions(-)

@@ -366,7 +366,7 @@ ifndef NO_SDT
 endif
 
 ifdef PERF_HAVE_JITDUMP
-  ifndef NO_DWARF
+  ifndef NO_LIBELF
     $(call detected,CONFIG_JITDUMP)
     CFLAGS += -DHAVE_JITDUMP
   endif

@@ -120,7 +120,7 @@ libperf-y += demangle-rust.o
 ifdef CONFIG_JITDUMP
 libperf-$(CONFIG_LIBELF) += jitdump.o
 libperf-$(CONFIG_LIBELF) += genelf.o
-libperf-$(CONFIG_LIBELF) += genelf_debug.o
+libperf-$(CONFIG_DWARF) += genelf_debug.o
 endif
 
 CFLAGS_config.o   += -DETC_PERFCONFIG="BUILD_STR($(ETC_PERFCONFIG_SQ))"

@@ -19,7 +19,9 @@
 #include <limits.h>
 #include <fcntl.h>
 #include <err.h>
+#ifdef HAVE_DWARF_SUPPORT
 #include <dwarf.h>
+#endif
 
 #include "perf.h"
 #include "genelf.h"

@@ -157,7 +159,7 @@ gen_build_id(struct buildid_note *note,
 int
 jit_write_elf(int fd, uint64_t load_addr, const char *sym,
 	      const void *code, int csize,
-	      void *debug, int nr_debug_entries)
+	      void *debug __maybe_unused, int nr_debug_entries __maybe_unused)
 {
 	Elf *e;
 	Elf_Data *d;

@@ -386,11 +388,14 @@ jit_write_elf(int fd, uint64_t load_addr
 	shdr->sh_size = sizeof(bnote);
 	shdr->sh_entsize = 0;
 
+#ifdef HAVE_DWARF_SUPPORT
 	if (debug && nr_debug_entries) {
 		retval = jit_add_debug_info(e, load_addr, debug, nr_debug_entries);
 		if (retval)
 			goto error;
-	} else {
+	} else
+#endif
+	{
 		if (elf_update(e, ELF_C_WRITE) < 0) {
 			warnx("elf_update 4 failed");
 			goto error;

@@ -4,8 +4,10 @@
 /* genelf.c */
 int jit_write_elf(int fd, uint64_t code_addr, const char *sym,
 		  const void *code, int csize, void *debug, int nr_debug_entries);
+#ifdef HAVE_DWARF_SUPPORT
 /* genelf_debug.c */
 int jit_add_debug_info(Elf *e, uint64_t code_addr, void *debug, int nr_debug_entries);
+#endif
 
 #if   defined(__arm__)
 #define GEN_ELF_ARCH	EM_ARM

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/perf-jit-enable-jitdump-support-without-dwarf.patch