+kern_return_t
+thread_fast_set_cthread_self64(uint64_t self)
+{
+ pcb_t pcb;
+ x86_saved_state64_t *iss;
+
+ pcb = current_thread()->machine.pcb;
+
+ /* check for canonical address, set 0 otherwise */
+ if (!IS_USERADDR64_CANONICAL(self))
+ self = 0ULL;
+ pcb->cthread_self = self;
+ current_cpu_datap()->cpu_uber.cu_user_gs_base = self;
+
+ /* XXX for 64-in-32 */
+ iss = saved_state64(pcb->iss);
+ iss->gs = USER_CTHREAD;
+ thread_compose_cthread_desc((uint32_t) self, pcb);
+
+ return (USER_CTHREAD);
+}
+
+/*
+ * thread_set_user_ldt routine is the interface for the user level
+ * settable ldt entry feature. allowing a user to create arbitrary
+ * ldt entries seems to be too large of a security hole, so instead
+ * this mechanism is in place to allow user level processes to have
+ * an ldt entry that can be used in conjunction with the FS register.
+ *
+ * Swapping occurs inside the pcb.c file along with initialization
+ * when a thread is created. The basic functioning theory is that the
+ * pcb->uldt_selector variable will contain either 0 meaning the
+ * process has not set up any entry, or the selector to be used in
+ * the FS register. pcb->uldt_desc contains the actual descriptor the
+ * user has set up stored in machine usable ldt format.
+ *
+ * Currently one entry is shared by all threads (USER_SETTABLE), but
+ * this could be changed in the future by changing how this routine
+ * allocates the selector. There seems to be no real reason at this
+ * time to have this added feature, but in the future it might be
+ * needed.
+ *
+ * address is the linear address of the start of the data area size
+ * is the size in bytes of the area flags should always be set to 0
+ * for now. in the future it could be used to set R/W permisions or
+ * other functions. Currently the segment is created as a data segment
+ * up to 1 megabyte in size with full read/write permisions only.
+ *
+ * this call returns the segment selector or -1 if any error occurs
+ */
+kern_return_t
+thread_set_user_ldt(uint32_t address, uint32_t size, uint32_t flags)
+{
+ pcb_t pcb;
+ struct fake_descriptor temp;
+ int mycpu;
+
+ if (flags != 0)
+ return -1; // flags not supported
+ if (size > 0xFFFFF)
+ return -1; // size too big, 1 meg is the limit
+
+ mp_disable_preemption();
+ mycpu = cpu_number();
+
+ // create a "fake" descriptor so we can use fix_desc()
+ // to build a real one...
+ // 32 bit default operation size
+ // standard read/write perms for a data segment
+ pcb = (pcb_t)current_thread()->machine.pcb;
+ temp.offset = address;
+ temp.lim_or_seg = size;
+ temp.size_or_wdct = SZ_32;
+ temp.access = ACC_P|ACC_PL_U|ACC_DATA_W;
+
+ // turn this into a real descriptor
+ fix_desc(&temp,1);
+
+ // set up our data in the pcb
+ pcb->uldt_desc = *(struct real_descriptor*)&temp;
+ pcb->uldt_selector = USER_SETTABLE; // set the selector value
+
+ // now set it up in the current table...
+ *ldt_desc_p(USER_SETTABLE) = *(struct real_descriptor*)&temp;
+
+ mp_enable_preemption();
+
+ return USER_SETTABLE;
+}
+
+#endif /* MACH_BSD */
+
+
+typedef kern_return_t (*mach_call_t)(void *);
+
+struct mach_call_args {
+ syscall_arg_t arg1;
+ syscall_arg_t arg2;
+ syscall_arg_t arg3;
+ syscall_arg_t arg4;
+ syscall_arg_t arg5;
+ syscall_arg_t arg6;
+ syscall_arg_t arg7;
+ syscall_arg_t arg8;
+ syscall_arg_t arg9;
+};
projects / apple / xnu.git / blobdiff