Simplified signal stack allocation a bit, and avoid allocating it on

dlls/kernel/thread.c

@@ -93,7 +93,7 @@ TEB *THREAD_InitStack( TEB *teb, DWORD stack_size )
         else
             stack_size = ((char *)NtCurrentTeb()->Tib.StackBase
                         - (char *)NtCurrentTeb()->DeallocationStack
-                        - SIGNAL_STACK_SIZE - 3 * page_size);
+                        - SIGNAL_STACK_SIZE);
     }
 
     /* FIXME: some Wine functions use a lot of stack, so we add 64Kb here */
@@ -102,16 +102,13 @@ TEB *THREAD_InitStack( TEB *teb, DWORD stack_size )
     /* Memory layout in allocated block:
      *
      *   size                 contents
-     * 1 page              NOACCESS guard page
      * SIGNAL_STACK_SIZE   signal stack
-     * 1 page              NOACCESS guard page
-     * 1 page              PAGE_GUARD guard page
-     * stack_size          normal stack
+     * stack_size          normal stack (including a PAGE_GUARD page at the bottom)
      * 1 page              TEB (except for initial thread)
      */
 
     stack_size = (stack_size + (page_size - 1)) & ~(page_size - 1);
-    total_size = stack_size + SIGNAL_STACK_SIZE + 3 * page_size;
+    total_size = stack_size + SIGNAL_STACK_SIZE;
     if (!teb) total_size += page_size;
 
     if (!(base = VirtualAlloc( NULL, total_size, MEM_COMMIT, PAGE_EXECUTE_READWRITE )))
@@ -128,15 +125,12 @@ TEB *THREAD_InitStack( TEB *teb, DWORD stack_size )
     }
 
     teb->DeallocationStack = base;
-    teb->signal_stack      = (char *)base + page_size;
-    teb->Tib.StackBase     = (char *)base + 3 * page_size + SIGNAL_STACK_SIZE + stack_size;
+    teb->Tib.StackBase     = (char *)base + SIGNAL_STACK_SIZE + stack_size;
     teb->Tib.StackLimit    = base;  /* note: limit is lower than base since the stack grows down */
 
     /* Setup guard pages */
 
-    VirtualProtect( base, 1, PAGE_NOACCESS, &old_prot );
-    VirtualProtect( (char *)teb->signal_stack + SIGNAL_STACK_SIZE, 1, PAGE_NOACCESS, &old_prot );
-    VirtualProtect( (char *)teb->signal_stack + SIGNAL_STACK_SIZE + page_size, 1,
+    VirtualProtect( (char *)base + SIGNAL_STACK_SIZE, 1,
                     PAGE_EXECUTE_READWRITE | PAGE_GUARD, &old_prot );
     return teb;
 }

dlls/ntdll/signal_i386.c

@@ -1172,15 +1172,15 @@ static int set_handler( int sig, int have_sigaltstack, void (*func)() )
     struct sigaction sig_act;
 
 #ifdef linux
-    if (!have_sigaltstack && NtCurrentTeb()->signal_stack)
+    if (!have_sigaltstack)
     {
         struct kernel_sigaction sig_act;
         sig_act.ksa_handler = func;
         sig_act.ksa_flags   = SA_RESTART;
         sig_act.ksa_mask    = (1 << (SIGINT-1)) |
                               (1 << (SIGUSR2-1));
-        /* point to the top of the stack */
-        sig_act.ksa_restorer = (char *)NtCurrentTeb()->signal_stack + SIGNAL_STACK_SIZE;
+        /* point to the top of the signal stack */
+        sig_act.ksa_restorer = (char *)NtCurrentTeb()->DeallocationStack + SIGNAL_STACK_SIZE;
         return wine_sigaction( sig, &sig_act, NULL );
     }
 #endif  /* linux */
@@ -1234,18 +1234,16 @@ BOOL SIGNAL_Init(void)
 
 #ifdef HAVE_SIGALTSTACK
     struct sigaltstack ss;
-    if ((ss.ss_sp = NtCurrentTeb()->signal_stack))
-    {
-        ss.ss_size  = SIGNAL_STACK_SIZE;
-        ss.ss_flags = 0;
-        if (!sigaltstack(&ss, NULL)) have_sigaltstack = 1;
+    ss.ss_sp    = NtCurrentTeb()->DeallocationStack;
+    ss.ss_size  = SIGNAL_STACK_SIZE;
+    ss.ss_flags = 0;
+    if (!sigaltstack(&ss, NULL)) have_sigaltstack = 1;
 #ifdef linux
-        /* sigaltstack may fail because the kernel is too old, or
-           because glibc is brain-dead. In the latter case a
-           direct system call should succeed. */
-        else if (!wine_sigaltstack(&ss, NULL)) have_sigaltstack = 1;
+    /* sigaltstack may fail because the kernel is too old, or
+       because glibc is brain-dead. In the latter case a
+       direct system call should succeed. */
+    else if (!wine_sigaltstack(&ss, NULL)) have_sigaltstack = 1;
 #endif  /* linux */
-    }
 #endif  /* HAVE_SIGALTSTACK */
 
     if (set_handler( SIGINT,  have_sigaltstack, (void (*)())int_handler ) == -1) goto error;

dlls/ntdll/virtual.c

@@ -832,14 +832,14 @@ DWORD VIRTUAL_HandleFault( LPCVOID addr )
         {
             BYTE vprot = view->prot[((char *)addr - (char *)view->base) >> page_shift];
             void *page = (void *)((UINT_PTR)addr & ~page_mask);
-            char *stack = (char *)NtCurrentTeb()->DeallocationStack + SIGNAL_STACK_SIZE + page_mask + 1;
+            char *stack = (char *)NtCurrentTeb()->DeallocationStack + SIGNAL_STACK_SIZE;
             if (vprot & VPROT_GUARD)
             {
                 VIRTUAL_SetProt( view, page, page_mask + 1, vprot & ~VPROT_GUARD );
                 ret = STATUS_GUARD_PAGE_VIOLATION;
             }
-            /* is it inside the stack guard pages? */
-            if (((char *)addr >= stack) && ((char *)addr < stack + 2*(page_mask+1)))
+            /* is it inside the stack guard page? */
+            if (((char *)addr >= stack) && ((char *)addr < stack + (page_mask+1)))
                 ret = STATUS_STACK_OVERFLOW;
         }
     }

include/thread.h

@@ -77,7 +77,7 @@ typedef struct _TEB
     DWORD        unknown3;       /* --n  48 */
     int          thread_errno;   /* --3  4c Per-thread errno (was: ring0_thread) */
     int          thread_h_errno; /* --3  50 Per-thread h_errno (was: ptr to tdbx structure) */
-    void        *signal_stack;   /* --3  54 Signal stack (was: stack_base) */
+    void        *stack_base;     /* 1-n  54 Stack base (unused) */
     void        *exit_stack;     /* 1-n  58 Exit stack */
     void        *emu_data;       /* --n  5c Related to 80387 emulation */
     DWORD        last_error;     /* 1--  60 Last error code */
@@ -141,7 +141,11 @@ typedef struct _TEB
 #define TEBF_TRAP   0x0002
 
 /* The per-thread signal stack size */
+#ifdef __i386__
 #define SIGNAL_STACK_SIZE  0x100000  /* 1Mb  FIXME: should be much smaller than that */
+#else
+#define SIGNAL_STACK_SIZE  0  /* we don't need a signal stack on non-i386 */
+#endif
 
 
 /* scheduler/thread.c */