From 0a67eba62de4be3c8f8bdd99dbbd4b8b74001700 Mon Sep 17 00:00:00 2001
From: David Benjamin <davidben@google.com>
Date: Sun, 3 Feb 2019 13:53:11 -0600
Subject: [PATCH] Fix the order of Windows unwind codes.

The unwind tester suggests Windows doesn't care, but the documentation
says that unwind codes should be sorted in descending offset, which
means the last instruction should be first.

https://docs.microsoft.com/en-us/cpp/build/exception-handling-x64?view=vs-2017#struct-unwind_code

Bug: 259
Change-Id: I21e54c362e18e0405f980005112cc3f7c417c70c
Reviewed-on: https://boringssl-review.googlesource.com/c/34785
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>
---
 .../modes/asm/ghash-ssse3-x86_64.pl           | 28 ++++++-------
 crypto/test/asm/trampoline-x86_64.pl          | 40 +++++++++----------
 2 files changed, 34 insertions(+), 34 deletions(-)

diff --git a/crypto/fipsmodule/modes/asm/ghash-ssse3-x86_64.pl b/crypto/fipsmodule/modes/asm/ghash-ssse3-x86_64.pl
index 830381b1..1dd25199 100644
--- a/crypto/fipsmodule/modes/asm/ghash-ssse3-x86_64.pl
+++ b/crypto/fipsmodule/modes/asm/ghash-ssse3-x86_64.pl
@@ -374,16 +374,16 @@ if ($win64) {
 	.byte	5	# num_slots = 1 + 2 + 2
 	.byte	0	# no frame register
 
-	.byte	.Lgmult_seh_allocstack-.Lgmult_seh_begin
-	.byte	@{[$UWOP_ALLOC_SMALL | (((40 - 8) / 8) << 4)]}
+	.byte	.Lgmult_seh_save_xmm10-.Lgmult_seh_begin
+	.byte	@{[$UWOP_SAVE_XMM128 | (10 << 4)]}
+	.value	1
 
 	.byte	.Lgmult_seh_save_xmm6-.Lgmult_seh_begin
 	.byte	@{[$UWOP_SAVE_XMM128 | (6 << 4)]}
 	.value	0
 
-	.byte	.Lgmult_seh_save_xmm10-.Lgmult_seh_begin
-	.byte	@{[$UWOP_SAVE_XMM128 | (10 << 4)]}
-	.value	1
+	.byte	.Lgmult_seh_allocstack-.Lgmult_seh_begin
+	.byte	@{[$UWOP_ALLOC_SMALL | (((40 - 8) / 8) << 4)]}
 
 .align	8
 .Lghash_seh_info:
@@ -392,20 +392,20 @@ if ($win64) {
 	.byte	7	# num_slots = 1 + 2 + 2 + 2
 	.byte	0	# no frame register
 
-	.byte	.Lghash_seh_allocstack-.Lghash_seh_begin
-	.byte	@{[$UWOP_ALLOC_SMALL | (((56 - 8) / 8) << 4)]}
-
-	.byte	.Lghash_seh_save_xmm6-.Lghash_seh_begin
-	.byte	@{[$UWOP_SAVE_XMM128 | (6 << 4)]}
-	.value	0
+	.byte	.Lghash_seh_save_xmm11-.Lghash_seh_begin
+	.byte	@{[$UWOP_SAVE_XMM128 | (11 << 4)]}
+	.value	2
 
 	.byte	.Lghash_seh_save_xmm10-.Lghash_seh_begin
 	.byte	@{[$UWOP_SAVE_XMM128 | (10 << 4)]}
 	.value	1
 
-	.byte	.Lghash_seh_save_xmm11-.Lghash_seh_begin
-	.byte	@{[$UWOP_SAVE_XMM128 | (11 << 4)]}
-	.value	2
+	.byte	.Lghash_seh_save_xmm6-.Lghash_seh_begin
+	.byte	@{[$UWOP_SAVE_XMM128 | (6 << 4)]}
+	.value	0
+
+	.byte	.Lghash_seh_allocstack-.Lghash_seh_begin
+	.byte	@{[$UWOP_ALLOC_SMALL | (((56 - 8) / 8) << 4)]}
 ____
 }
 
diff --git a/crypto/test/asm/trampoline-x86_64.pl b/crypto/test/asm/trampoline-x86_64.pl
index 75aae459..8cb14108 100755
--- a/crypto/test/asm/trampoline-x86_64.pl
+++ b/crypto/test/asm/trampoline-x86_64.pl
@@ -447,26 +447,7 @@ ____
 
   my $unwind_codes = "";
   my $num_slots = 0;
-  if ($stack_alloc_size <= 128) {
-    my $info = $UWOP_ALLOC_SMALL | ((($stack_alloc_size - 8) / 8) << 4);
-    $unwind_codes .= <<____;
-	.byte	.Labi_test_trampoline_seh_prolog_alloc-.Labi_test_trampoline_seh_begin
-	.byte	$info
-____
-    $num_slots++;
-  } else {
-    die "stack allocation needs three unwind slots" if ($stack_alloc_size > 512 * 1024 + 8);
-    my $info = $UWOP_ALLOC_LARGE;
-    my $value = $stack_alloc_size / 8;
-    $unwind_codes .= <<____;
-	.byte	.Labi_test_trampoline_seh_prolog_alloc-.Labi_test_trampoline_seh_begin
-	.byte	$info
-	.value	$value
-____
-    $num_slots += 2;
-  }
-
-  foreach my $reg (@caller_state) {
+  foreach my $reg (reverse @caller_state) {
     $reg = substr($reg, 1);
     die "unknown register $reg" unless exists($reg_offsets{$reg});
     if ($reg =~ /^r/) {
@@ -493,6 +474,25 @@ ____
     }
   }
 
+  if ($stack_alloc_size <= 128) {
+    my $info = $UWOP_ALLOC_SMALL | ((($stack_alloc_size - 8) / 8) << 4);
+    $unwind_codes .= <<____;
+	.byte	.Labi_test_trampoline_seh_prolog_alloc-.Labi_test_trampoline_seh_begin
+	.byte	$info
+____
+    $num_slots++;
+  } else {
+    die "stack allocation needs three unwind slots" if ($stack_alloc_size > 512 * 1024 + 8);
+    my $info = $UWOP_ALLOC_LARGE;
+    my $value = $stack_alloc_size / 8;
+    $unwind_codes .= <<____;
+	.byte	.Labi_test_trampoline_seh_prolog_alloc-.Labi_test_trampoline_seh_begin
+	.byte	$info
+	.value	$value
+____
+    $num_slots += 2;
+  }
+
   $code .= <<____;
 .section	.pdata
 .align	4