Merge tag 'objtool-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull objtool updates from Ingo Molnar:

 - Standardize the crypto asm code so that it looks like compiler-
   generated code to objtool - so that it can understand it. This
   enables unwinding from crypto asm code - and also fixes the last
   known remaining objtool warnings for LTO and more.

 - x86 decoder fixes: clean up and fix the decoder, and also extend it a
   bit

 - Misc fixes and cleanups

* tag 'objtool-core-2021-04-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  x86/crypto: Enable objtool in crypto code
  x86/crypto/sha512-ssse3: Standardize stack alignment prologue
  x86/crypto/sha512-avx2: Standardize stack alignment prologue
  x86/crypto/sha512-avx: Standardize stack alignment prologue
  x86/crypto/sha256-avx2: Standardize stack alignment prologue
  x86/crypto/sha1_avx2: Standardize stack alignment prologue
  x86/crypto/sha_ni: Standardize stack alignment prologue
  x86/crypto/crc32c-pcl-intel: Standardize jump table
  x86/crypto/camellia-aesni-avx2: Unconditionally allocate stack buffer
  x86/crypto/aesni-intel_avx: Standardize stack alignment prologue
  x86/crypto/aesni-intel_avx: Fix register usage comments
  x86/crypto/aesni-intel_avx: Remove unused macros
  objtool: Support asm jump tables
  objtool: Parse options from OBJTOOL_ARGS
  objtool: Collate parse_options() users
  objtool: Add --backup
  objtool,x86: More ModRM sugar
  objtool,x86: Rewrite ADD/SUB/AND
  objtool,x86: Support %riz encodings
  objtool,x86: Simplify register decode
  ...

1 files changed, 64 insertions, 0 deletions

diff --git a/tools/objtool/objtool.c b/tools/objtool/objtool.c
index 3a3ea1b4e4da..e21db8bce493 100644
--- a/tools/objtool/objtool.c
+++ b/tools/objtool/objtool.c
@@ -17,6 +17,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <stdlib.h>
+#include <unistd.h>
 #include <subcmd/exec-cmd.h>
 #include <subcmd/pager.h>
 #include <linux/kernel.h>
@@ -44,6 +45,64 @@ bool help;
 const char *objname;
 static struct objtool_file file;
 
+static bool objtool_create_backup(const char *_objname)
+{
+	int len = strlen(_objname);
+	char *buf, *base, *name = malloc(len+6);
+	int s, d, l, t;
+
+	if (!name) {
+		perror("failed backup name malloc");
+		return false;
+	}
+
+	strcpy(name, _objname);
+	strcpy(name + len, ".orig");
+
+	d = open(name, O_CREAT|O_WRONLY|O_TRUNC, 0644);
+	if (d < 0) {
+		perror("failed to create backup file");
+		return false;
+	}
+
+	s = open(_objname, O_RDONLY);
+	if (s < 0) {
+		perror("failed to open orig file");
+		return false;
+	}
+
+	buf = malloc(4096);
+	if (!buf) {
+		perror("failed backup data malloc");
+		return false;
+	}
+
+	while ((l = read(s, buf, 4096)) > 0) {
+		base = buf;
+		do {
+			t = write(d, base, l);
+			if (t < 0) {
+				perror("failed backup write");
+				return false;
+			}
+			base += t;
+			l -= t;
+		} while (l);
+	}
+
+	if (l < 0) {
+		perror("failed backup read");
+		return false;
+	}
+
+	free(name);
+	free(buf);
+	close(d);
+	close(s);
+
+	return true;
+}
+
 struct objtool_file *objtool_open_read(const char *_objname)
 {
 	if (objname) {
@@ -59,6 +118,11 @@ struct objtool_file *objtool_open_read(const char *_objname)
 	if (!file.elf)
 		return NULL;
 
+	if (backup && !objtool_create_backup(objname)) {
+		WARN("can't create backup file");
+		return NULL;
+	}
+
 	INIT_LIST_HEAD(&file.insn_list);
 	hash_init(file.insn_hash);
 	INIT_LIST_HEAD(&file.retpoline_call_list);