[tip: x86/build] x86/tools: objdump_reformat.awk: Ensure regex matches fwait

["tip-bot2 for Samuel Zeter" <tip-bot2@xxxxxxxxxxxxx>]

The following commit has been merged into the x86/build branch of tip:

Commit-ID:     60c2ea7c89e375804171552d8ea53d9084ec3269
Gitweb:        https://git.kernel.org/tip/60c2ea7c89e375804171552d8ea53d9084ec3269
Author:        Samuel Zeter <samuelzeter@xxxxxxxxx>
AuthorDate:    Wed, 29 Nov 2023 15:17:41 -07:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Thu, 30 Nov 2023 09:38:09 +01:00

x86/tools: objdump_reformat.awk: Ensure regex matches fwait

If there is "wait" mnemonic in the line being parsed, it is incorrectly
handled by the script, and an extra line of "fwait" in
objdump_reformat's output is inserted. As insn_decoder_test relies upon
the formatted output, the test fails.

This is reproducible when disassembling with llvm-objdump:

Pre-processed lines:

  ffffffff81033e72: 9b                    wait
  ffffffff81033e73: 48 c7 c7 89 50 42 82  movq

After objdump_reformat.awk:

  ffffffff81033e72:       9b      fwait
  ffffffff81033e72:                               wait
  ffffffff81033e73:       48 c7 c7 89 50 42 82    movq

The regex match now accepts spaces or tabs, along with the "fwait"
instruction.

Signed-off-by: Samuel Zeter <samuelzeter@xxxxxxxxx>
Signed-off-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Tested-by: Nathan Chancellor <nathan@xxxxxxxxxx>
Tested-by: Kees Cook <keescook@xxxxxxxxxxxx>
Reviewed-by: Kees Cook <keescook@xxxxxxxxxxxx>
Acked-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231129-objdump-reformat-llvm-v3-1-0d855e79314d@xxxxxxxxxx
Closes: https://github.com/ClangBuiltLinux/linux/issues/1364
---
 arch/x86/tools/objdump_reformat.awk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/tools/objdump_reformat.awk b/arch/x86/tools/objdump_reformat.awk
index f418c91..276e572 100644
--- a/arch/x86/tools/objdump_reformat.awk
+++ b/arch/x86/tools/objdump_reformat.awk
@@ -12,7 +12,7 @@ BEGIN {
 	prev_hex = ""
 	prev_mnemonic = ""
 	bad_expr = "(\\(bad\\)|^rex|^.byte|^rep(z|nz)$|^lock$|^es$|^cs$|^ss$|^ds$|^fs$|^gs$|^data(16|32)$|^addr(16|32|64))"
-	fwait_expr = "^9b "
+	fwait_expr = "^9b[ \t]*fwait"
 	fwait_str="9b\tfwait"
 }