Sebastian Lackner : winebuild: Conditionally use different code for restoring the context structure.

[Alexandre Julliard]

Module: wine
Branch: master
Commit: 4c8b3f63be19e188fd379e9294df4a7eabb9198b
URL:    http://source.winehq.org/git/wine.git/?a=commit;h=4c8b3f63be19e188fd379e9294...

Author: Sebastian Lackner <sebastian(a)fds-team.de>
Date:   Mon Mar  2 00:29:42 2015 +0100

winebuild: Conditionally use different code for restoring the context structure.

Fixes a regression introduced by 44fbc018eda12bdee5c2c1e2e40dbdc6a81b27fd.

---

 tools/winebuild/relay.c | 57 +++++++++++++++++++++++++++++++++++--------------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/tools/winebuild/relay.c b/tools/winebuild/relay.c
index 63c2ca4..cb4b0ca 100644
--- a/tools/winebuild/relay.c
+++ b/tools/winebuild/relay.c
@@ -852,36 +852,35 @@ static void build_call_from_regs_x86(void)
 
     /* Restore the context structure */
 
-    output( "2:\n" );
+    output( "2:\tpushl 0x94(%%ecx)\n" );    /* SegEs */
+    output( "\tpopl %%es\n" );
+    output( "\tpushl 0x90(%%ecx)\n" );      /* SegFs */
+    output( "\tpopl %%fs\n" );
+    output( "\tpushl 0x8c(%%ecx)\n" );      /* SegGs */
+    output( "\tpopl %%gs\n" );
+
+    output( "\tmovw %%ss,%%ax\n" );
+    output( "\tcmpw 0xc8(%%ecx),%%ax\n" );  /* SegSs */
+    output( "\tjne 3f\n" );
 
     /* As soon as we have switched stacks the context structure could
      * be invalid (when signal handlers are executed for example). Copy
      * values on the target stack before changing ESP. */
 
-    output( "\tpushl 0xc8(%%ecx)\n" );      /* SegSs */
-    output( "\tpopl %%es\n" );
     output( "\tmovl 0xc4(%%ecx),%%eax\n" ); /* Esp */
     output( "\tleal -4*4(%%eax),%%eax\n" );
 
     output( "\tmovl 0xc0(%%ecx),%%edx\n" ); /* EFlags */
-    output( "\t.byte 0x26\n\tmovl %%edx,3*4(%%eax)\n" );
+    output( "\t.byte 0x36\n\tmovl %%edx,3*4(%%eax)\n" );
     output( "\tmovl 0xbc(%%ecx),%%edx\n" ); /* SegCs */
-    output( "\t.byte 0x26\n\tmovl %%edx,2*4(%%eax)\n" );
+    output( "\t.byte 0x36\n\tmovl %%edx,2*4(%%eax)\n" );
     output( "\tmovl 0xb8(%%ecx),%%edx\n" ); /* Eip */
-    output( "\t.byte 0x26\n\tmovl %%edx,1*4(%%eax)\n" );
+    output( "\t.byte 0x36\n\tmovl %%edx,1*4(%%eax)\n" );
     output( "\tmovl 0xb0(%%ecx),%%edx\n" ); /* Eax */
-    output( "\t.byte 0x26\n\tmovl %%edx,0*4(%%eax)\n" );
+    output( "\t.byte 0x36\n\tmovl %%edx,0*4(%%eax)\n" );
 
-    output( "\tpushl %%es\n" );
     output( "\tpushl 0x98(%%ecx)\n" );      /* SegDs */
 
-    output(" \tpushl 0x94(%%ecx)\n" );      /* SegEs */
-    output( "\tpopl %%es\n" );
-    output( "\tpushl 0x90(%%ecx)\n");       /* SegFs */
-    output( "\tpopl %%fs\n" );
-    output( "\tpushl 0x8c(%%ecx)\n");       /* SegGs */
-    output( "\tpopl %%gs\n" );
-
     output( "\tmovl 0x9c(%%ecx),%%edi\n" ); /* Edi */
     output( "\tmovl 0xa0(%%ecx),%%esi\n" ); /* Esi */
     output( "\tmovl 0xa4(%%ecx),%%ebx\n" ); /* Ebx */
@@ -890,11 +889,37 @@ static void build_call_from_regs_x86(void)
     output( "\tmovl 0xac(%%ecx),%%ecx\n" ); /* Ecx */
 
     output( "\tpopl %%ds\n" );
-    output( "\tpopl %%ss\n" );
     output( "\tmovl %%eax,%%esp\n" );
 
     output( "\tpopl %%eax\n" );
     output( "\tiret\n" );
+
+    output("3:\n");
+
+    /* Restore the context when the stack segment changes. We can't use
+     * the same code as above because we do not know if the stack segment
+     * is 16 or 32 bit, and 'movl' will throw an exception when we try to
+     * access memory above the limit. */
+
+    output( "\tmovl 0x9c(%%ecx),%%edi\n" ); /* Edi */
+    output( "\tmovl 0xa0(%%ecx),%%esi\n" ); /* Esi */
+    output( "\tmovl 0xa4(%%ecx),%%ebx\n" ); /* Ebx */
+    output( "\tmovl 0xa8(%%ecx),%%edx\n" ); /* Edx */
+    output( "\tmovl 0xb0(%%ecx),%%eax\n" ); /* Eax */
+    output( "\tmovl 0xb4(%%ecx),%%ebp\n" ); /* Ebp */
+
+    output( "\tpushl 0xc8(%%ecx)\n" );      /* SegSs */
+    output( "\tpopl %%ss\n" );
+    output( "\tmovl 0xc4(%%ecx),%%esp\n" ); /* Esp */
+
+    output( "\tpushl 0xc0(%%ecx)\n" );      /* EFlags */
+    output( "\tpushl 0xbc(%%ecx)\n" );      /* SegCs */
+    output( "\tpushl 0xb8(%%ecx)\n" );      /* Eip */
+    output( "\tpushl 0x98(%%ecx)\n" );      /* SegDs */
+    output( "\tmovl 0xac(%%ecx),%%ecx\n" ); /* Ecx */
+
+    output( "\tpopl %%ds\n" );
+    output( "\tiret\n" );
     output_cfi( ".cfi_endproc" );
     output_function_size( "__wine_call_from_regs" );