a75869f0b2
Bug: 11156955 Change-Id: If82c10ae412651361d09591017d1c3a411bd6f0b
75 lines
2.6 KiB
C
75 lines
2.6 KiB
C
/*
|
|
* Copyright (C) 2008 The Android Open Source Project
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* * Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* * Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
|
|
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
|
|
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*/
|
|
|
|
#include <limits.h>
|
|
#include <pthread.h>
|
|
#include <stdbool.h>
|
|
|
|
#include <asm/ldt.h>
|
|
|
|
extern int __set_thread_area(struct user_desc*);
|
|
|
|
__LIBC_HIDDEN__ void __init_user_desc(struct user_desc* result, bool allocate, void* base_addr) {
|
|
if (allocate) {
|
|
// Let the kernel choose.
|
|
result->entry_number = -1;
|
|
} else {
|
|
// Get the existing entry number from %gs.
|
|
uint32_t gs;
|
|
__asm__ __volatile__("movw %%gs, %w0" : "=q"(gs) /*output*/);
|
|
result->entry_number = (gs & 0xffff) >> 3;
|
|
}
|
|
|
|
result->base_addr = (uintptr_t) base_addr;
|
|
|
|
result->limit = PAGE_SIZE;
|
|
|
|
result->seg_32bit = 1;
|
|
result->contents = MODIFY_LDT_CONTENTS_DATA;
|
|
result->read_exec_only = 0;
|
|
result->limit_in_pages = 1;
|
|
result->seg_not_present = 0;
|
|
result->useable = 1;
|
|
}
|
|
|
|
__LIBC_HIDDEN__ int __set_tls(void* ptr) {
|
|
struct user_desc tls_descriptor;
|
|
__init_user_desc(&tls_descriptor, true, ptr);
|
|
|
|
int rc = __set_thread_area(&tls_descriptor);
|
|
if (rc != -1) {
|
|
// Change %gs to be new GDT entry.
|
|
uint16_t table_indicator = 0; // GDT
|
|
uint16_t rpl = 3; // Requested privilege level
|
|
uint16_t selector = (tls_descriptor.entry_number << 3) | table_indicator | rpl;
|
|
__asm__ __volatile__("movw %w0, %%gs" : /*output*/ : "q"(selector) /*input*/ : /*clobber*/);
|
|
}
|
|
|
|
return rc;
|
|
}
|