Instead of the whole stack.
Stack creation in virtual_alloc_thread_stack and RtlCreateUserStack, as well as Windows rounding logic, enforce a minimum reserved size of 1MB.
There's a few guard and canary pages used on the bottom, plus a few more on the top for initial context, and we have to keep a bit of space if we ever need a stack while doing this, so we clear a bit less than 1MB to be safe.
Signed-off-by: Rémi Bernon rbernon@codeweavers.com --- dlls/ntdll/signal_i386.c | 4 ++-- dlls/ntdll/signal_x86_64.c | 5 ++--- 2 files changed, 4 insertions(+), 5 deletions(-)
diff --git a/dlls/ntdll/signal_i386.c b/dlls/ntdll/signal_i386.c index 635b8f4de81..7261d398942 100644 --- a/dlls/ntdll/signal_i386.c +++ b/dlls/ntdll/signal_i386.c @@ -507,8 +507,8 @@ __ASM_GLOBAL_FUNC( signal_start_thread, "leal -12(%esi),%ecx\n\t" /* clear the thread stack */ "andl $~0xfff,%ecx\n\t" /* round down to page size */ - "movl %fs:8,%edi\n\t" /* NtCurrentTeb()->Tib.StackLimit */ - "addl $0x1000,%edi\n\t" + "movl %ecx,%edi\n\t" + "subl $0xf0000,%edi\n\t" "movl %edi,%esp\n\t" "subl %edi,%ecx\n\t" "xorl %eax,%eax\n\t" diff --git a/dlls/ntdll/signal_x86_64.c b/dlls/ntdll/signal_x86_64.c index d88f7ae553a..be8d6e22330 100644 --- a/dlls/ntdll/signal_x86_64.c +++ b/dlls/ntdll/signal_x86_64.c @@ -1544,9 +1544,8 @@ __ASM_GLOBAL_FUNC( signal_start_thread, "movq %rcx,%rbx\n\t" /* context */ /* clear the thread stack */ "andq $~0xfff,%rcx\n\t" /* round down to page size */ - "movq %gs:0x30,%rax\n\t" - "movq 0x10(%rax),%rdi\n\t" /* NtCurrentTeb()->Tib.StackLimit */ - "addq $0x2000,%rdi\n\t" + "movq %rcx,%rdi\n\t" + "subq $0xf0000,%rdi\n\t" "movq %rdi,%rsp\n\t" "subq %rdi,%rcx\n\t" "xorl %eax,%eax\n\t"