diff options
| -rw-r--r-- | i386/i386/user_ldt.c | 82 |
1 files changed, 47 insertions, 35 deletions
diff --git a/i386/i386/user_ldt.c b/i386/i386/user_ldt.c index 71ca08d..5c5df64 100644 --- a/i386/i386/user_ldt.c +++ b/i386/i386/user_ldt.c @@ -37,6 +37,7 @@ #include <i386/thread.h> #include <i386/user_ldt.h> #include "ldt.h" +#include "vm_param.h" char acc_type[8][3] = { /* code stack data */ @@ -100,9 +101,10 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline) unsigned int count; boolean_t desc_list_inline; { - user_ldt_t new_ldt, old_ldt, cur_ldt; + user_ldt_t new_ldt, old_ldt, temp; struct real_descriptor *dp; int i; + int min_selector = 0; pcb_t pcb; vm_size_t ldt_size_needed; int first_desc = sel_idx(first_selector); @@ -110,7 +112,9 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline) if (thread == THREAD_NULL) return KERN_INVALID_ARGUMENT; - if (first_desc < 0 || first_desc > 8191) + if (thread == current_thread()) + min_selector = LDTSZ; + if (first_desc < min_selector || first_desc > 8191) return KERN_INVALID_ARGUMENT; if (first_desc + count >= 8192) return KERN_INVALID_ARGUMENT; @@ -172,19 +176,18 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline) } } ldt_size_needed = sizeof(struct real_descriptor) - * (first_desc + count - 1); + * (first_desc + count); pcb = thread->pcb; - old_ldt = 0; /* the one to throw away */ - new_ldt = 0; /* the one to allocate */ + new_ldt = 0; Retry: simple_lock(&pcb->lock); - cur_ldt = pcb->ims.ldt; - if (cur_ldt == 0 || - cur_ldt->desc.limit_low + 1 < ldt_size_needed) + old_ldt = pcb->ims.ldt; + if (old_ldt == 0 || + old_ldt->desc.limit_low + 1 < ldt_size_needed) { /* - * No current LDT, or not big enough + * No old LDT, or not big enough */ if (new_ldt == 0) { simple_unlock(&pcb->lock); @@ -199,7 +202,7 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline) { vm_offset_t ldt_base; - ldt_base = (vm_offset_t) &new_ldt->ldt[0]; + ldt_base = kvtolin(&new_ldt->ldt[0]); new_ldt->desc.limit_low = ldt_size_needed - 1; new_ldt->desc.limit_high = 0; @@ -214,40 +217,48 @@ i386_set_ldt(thread, first_selector, desc_list, count, desc_list_inline) } /* - * Have new LDT. Copy descriptors from current to new. + * Have new LDT. If there was a an old ldt, copy descriptors + * from old to new. Otherwise copy the default ldt. */ - if (cur_ldt) - bcopy((char *) &cur_ldt->ldt[0], - (char *) &new_ldt->ldt[0], - cur_ldt->desc.limit_low + 1); - - old_ldt = cur_ldt; /* discard old LDT */ - cur_ldt = new_ldt; /* use new LDT from now on */ - new_ldt = 0; /* keep new LDT */ + if (old_ldt) { + bcopy((char *)&old_ldt->ldt[0], + (char *)&new_ldt->ldt[0], + old_ldt->desc.limit_low + 1); + } + else if (thread == current_thread()) { + struct real_descriptor template = {0, 0, 0, ACC_P, 0, 0 ,0}; + + for (dp = &new_ldt->ldt[0], i = 0; i < first_desc; i++, dp++) { + if (i < LDTSZ) + *dp = *(struct real_descriptor *) &ldt[i]; + else + *dp = template; + } + } + + temp = old_ldt; + old_ldt = new_ldt; /* use new LDT from now on */ + new_ldt = temp; /* discard old LDT */ - pcb->ims.ldt = cur_ldt; /* set LDT for thread */ + pcb->ims.ldt = old_ldt; /* set LDT for thread */ + + /* + * If we are modifying the LDT for the current thread, + * make sure it is properly set. + */ + if (thread == current_thread()) + switch_ktss(pcb); } /* * Install new descriptors. */ - bcopy((char *) desc_list, - (char *) &cur_ldt->ldt[first_desc], + bcopy((char *)desc_list, + (char *)&old_ldt->ldt[first_desc], count * sizeof(struct real_descriptor)); simple_unlock(&pcb->lock); - /* - * Discard old LDT if it was replaced - */ - if (old_ldt) - kfree((vm_offset_t)old_ldt, - old_ldt->desc.limit_low + 1 - + sizeof(struct real_descriptor)); - - /* - * Discard new LDT if it was not used - */ if (new_ldt) kfree((vm_offset_t)new_ldt, new_ldt->desc.limit_low + 1 @@ -344,7 +355,7 @@ i386_get_ldt(thread, first_selector, selector_count, desc_list, count) /* * copy out the descriptors */ - bcopy((char *)&user_ldt[first_desc], + bcopy((char *)&user_ldt->ldt[first_desc], (char *)*desc_list, ldt_size); *count = ldt_count; @@ -372,7 +383,8 @@ i386_get_ldt(thread, first_selector, selector_count, desc_list, count) /* * Make memory into copyin form - this unwires it. */ - (void) vm_map_copyin(ipc_kernel_map, addr, size_used, TRUE, &memory); + (void) vm_map_copyin(ipc_kernel_map, addr, size_used, + TRUE, &memory); *desc_list = (struct real_descriptor *)memory; } |