perf kcore_copy: Keep phdr data in a list

Currently, kcore_copy makes 2 program headers, one for the kernel text
(namely kernel_map) and one for the modules (namely modules_map). Now
more program headers are needed, but treating each program header as a
special case results in much more code.

Instead, in preparation to add more program headers, change to keep
program header data (phdr_data) in a list.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/1526986485-6562-11-git-send-email-adrian.hunter@intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/symbol-elf.c

@@ -1388,6 +1388,7 @@ struct phdr_data {
 	off_t offset;
 	u64 addr;
 	u64 len;
+	struct list_head node;
 };
 
 struct kcore_copy_info {
@@ -1399,6 +1400,7 @@ struct kcore_copy_info {
 	u64 last_module_symbol;
 	struct phdr_data kernel_map;
 	struct phdr_data modules_map;
+	struct list_head phdrs;
 };
 
 static int kcore_copy__process_kallsyms(void *arg, const char *name, char type,
@@ -1510,6 +1512,11 @@ static int kcore_copy__read_maps(struct kcore_copy_info *kci, Elf *elf)
 	if (elf_read_maps(elf, true, kcore_copy__read_map, kci) < 0)
 		return -1;
 
+	if (kci->kernel_map.len)
+		list_add_tail(&kci->kernel_map.node, &kci->phdrs);
+	if (kci->modules_map.len)
+		list_add_tail(&kci->modules_map.node, &kci->phdrs);
+
 	return 0;
 }
 
@@ -1678,6 +1685,8 @@ int kcore_copy(const char *from_dir, const char *to_dir)
 	char kcore_filename[PATH_MAX];
 	char extract_filename[PATH_MAX];
 
+	INIT_LIST_HEAD(&kci.phdrs);
+
 	if (kcore_copy__copy_file(from_dir, to_dir, "kallsyms"))
 		return -1;