preloader: Setup a fake thread-local storage block pointed to by %gs.
diff --git a/loader/preloader.c b/loader/preloader.c
index 7140f3a..bd303da 100644
--- a/loader/preloader.c
+++ b/loader/preloader.c
@@ -163,6 +163,26 @@
void *__stack_chk_guard = 0;
void __stack_chk_fail(void) { return; }
+/* data for setting up the glibc-style thread-local storage in %gs */
+
+static int thread_data[256];
+
+struct
+{
+ /* this is the kernel modify_ldt struct */
+ unsigned int entry_number;
+ unsigned long base_addr;
+ unsigned int limit;
+ unsigned int seg_32bit : 1;
+ unsigned int contents : 2;
+ unsigned int read_exec_only : 1;
+ unsigned int limit_in_pages : 1;
+ unsigned int seg_not_present : 1;
+ unsigned int useable : 1;
+ unsigned int garbage : 25;
+} thread_ldt = { -1, (unsigned long)thread_data, 0xfffff, 1, 0, 0, 1, 0, 1, 0 };
+
+
/*
* The _start function is the entry and exit point of this program
*
@@ -172,7 +192,17 @@
void _start();
extern char _end[];
__ASM_GLOBAL_FUNC(_start,
- "\tmovl %esp,%eax\n"
+ "\tmovl $243,%eax\n" /* SYS_set_thread_area */
+ "\tmovl $thread_ldt,%ebx\n"
+ "\tint $0x80\n" /* allocate gs segment */
+ "\torl %eax,%eax\n"
+ "\tjl 1f\n"
+ "\tmovl thread_ldt,%eax\n" /* thread_ldt.entry_number */
+ "\tshl $3,%eax\n"
+ "\torl $3,%eax\n"
+ "\tmov %ax,%gs\n"
+ "\tmov %ax,%fs\n" /* set %fs too so libwine can retrieve it later on */
+ "1:\tmovl %esp,%eax\n"
"\tleal -136(%esp),%esp\n" /* allocate some space for extra aux values */
"\tpushl %eax\n" /* orig stack pointer */
"\tpushl %esp\n" /* ptr to orig stack pointer */
