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sortix--sortix/libpthread/pthread_create.c++
Jonas 'Sortie' Termansen 30cd318c17 Implement signals.
Note: This is an incompatible ABI change.
2014-07-22 13:25:39 +02:00

240 lines
8.5 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013, 2014.
This file is part of Sortix libpthread.
Sortix libpthread is free software: you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by the
Free Software Foundation, either version 3 of the License, or (at your
option) any later version.
Sortix libpthread is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with Sortix libpthread. If not, see <http://www.gnu.org/licenses/>.
pthread_create.c++
Creates a new thread.
*******************************************************************************/
#include <sys/mman.h>
#include <assert.h>
#include <errno.h>
#include <signal.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <unistd.h>
// Utility function that rounds size upwards to a multiple of alignment.
static size_t align_size(size_t size, size_t alignment)
{
return -(-size & ~(alignment-1));
}
__attribute__((noreturn))
static void pthread_entrance(struct pthread* thread)
{
pthread_exit(thread->entry_function(thread->entry_cookie));
}
#if defined(__i386__) || defined(__x86_64__)
const unsigned long FLAGS_CARRY = 1 << 0; // 0x000001
const unsigned long FLAGS_RESERVED1 = 1 << 1; // 0x000002, read as one
const unsigned long FLAGS_PARITY = 1 << 2; // 0x000004
const unsigned long FLAGS_RESERVED2 = 1 << 3; // 0x000008
const unsigned long FLAGS_AUX = 1 << 4; // 0x000010
const unsigned long FLAGS_RESERVED3 = 1 << 5; // 0x000020
const unsigned long FLAGS_ZERO = 1 << 6; // 0x000040
const unsigned long FLAGS_SIGN = 1 << 7; // 0x000080
const unsigned long FLAGS_TRAP = 1 << 8; // 0x000100
const unsigned long FLAGS_INTERRUPT = 1 << 9; // 0x000200
const unsigned long FLAGS_DIRECTION = 1 << 10; // 0x000400
const unsigned long FLAGS_OVERFLOW = 1 << 11; // 0x000800
const unsigned long FLAGS_IOPRIVLEVEL = 1 << 12 | 1 << 13;
const unsigned long FLAGS_NESTEDTASK = 1 << 14; // 0x004000
const unsigned long FLAGS_RESERVED4 = 1 << 15; // 0x008000
const unsigned long FLAGS_RESUME = 1 << 16; // 0x010000
const unsigned long FLAGS_VIRTUAL8086 = 1 << 17; // 0x020000
const unsigned long FLAGS_ALIGNCHECK = 1 << 18; // 0x040000
const unsigned long FLAGS_VIRTINTR = 1 << 19; // 0x080000
const unsigned long FLAGS_VIRTINTRPEND = 1 << 20; // 0x100000
const unsigned long FLAGS_ID = 1 << 21; // 0x200000
#endif
#if defined(__i386__)
static const unsigned long MINIMUM_STACK_SIZE = 4 * sizeof(unsigned long);
static void setup_thread_state(struct pthread* thread, struct tfork* regs)
{
assert(MINIMUM_STACK_SIZE <= thread->uthread.stack_size);
memset(regs, 0, sizeof(*regs));
regs->eip = (uintptr_t) pthread_entrance;
regs->eflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
regs->gsbase = (unsigned long) thread;
unsigned long* stack =
(unsigned long*) ((uint8_t*) thread->uthread.stack_mmap +
thread->uthread.stack_size);
*--stack = 0; // rip=0
*--stack = 0; // rbp=0
regs->ebp = (uintptr_t) stack;
*--stack = (unsigned long) thread;
*--stack = 0;
regs->esp = (uintptr_t) stack;
}
#endif
#if defined(__x86_64__)
static const unsigned long MINIMUM_STACK_SIZE = 2 * sizeof(unsigned long);
static void setup_thread_state(struct pthread* thread, struct tfork* regs)
{
assert(MINIMUM_STACK_SIZE <= thread->uthread.stack_size);
memset(regs, 0, sizeof(*regs));
regs->rip = (uintptr_t) pthread_entrance;
regs->rdi = (uintptr_t) thread;
regs->rflags = FLAGS_RESERVED1 | FLAGS_INTERRUPT | FLAGS_ID;
regs->fsbase = (unsigned long) thread;
unsigned long* stack =
(unsigned long*) ((uint8_t*) thread->uthread.stack_mmap +
thread->uthread.stack_size);
*--stack = 0; // rip=0
*--stack = 0; // rbp=0
regs->rsp = (uintptr_t) stack;
regs->rbp = regs->rsp;
}
#endif
extern "C"
int pthread_create(pthread_t* restrict thread_ptr,
const pthread_attr_t* restrict attr,
void* (*entry_function)(void*),
void* restrict entry_cookie)
{
assert(thread_ptr);
pthread_attr_t default_attr;
if ( !attr )
{
pthread_attr_init(&default_attr);
attr = &default_attr;
}
struct pthread* self = pthread_self();
// We can't create a thread local storage copy (and thus a new thread) if
// the kernel failed to allocate the thread local storage master copy.
if ( self->uthread.tls_master_size && !self->uthread.tls_master_mmap )
return errno = ENOMEM;
size_t raw_tls_size = self->uthread.tls_master_size;
size_t raw_tls_size_aligned = align_size(raw_tls_size, self->uthread.tls_master_align);
if ( raw_tls_size && raw_tls_size_aligned == 0 /* overflow */ )
return errno = EINVAL;
size_t tls_size = raw_tls_size_aligned + sizeof(struct pthread);
size_t tls_offset_tls = 0;
size_t tls_offset_pthread = raw_tls_size_aligned;
if ( self->uthread.tls_master_align < alignof(struct pthread) )
{
size_t more_aligned = align_size(raw_tls_size_aligned, alignof(struct pthread));
if ( raw_tls_size_aligned && more_aligned == 0 /* overflow */ )
return errno = EINVAL;
size_t difference = more_aligned - raw_tls_size_aligned;
tls_size += difference;
tls_offset_tls += difference;
tls_offset_pthread += difference;
}
assert((tls_offset_tls & (self->uthread.tls_master_align-1)) == 0);
assert((tls_offset_pthread & (alignof(struct pthread)-1)) == 0);
// Allocate a copy of the base thread-local storage area for use by the new
// thread, followed by the struct pthread for the new thread.
int prot = PROT_READ | PROT_WRITE;
int flags = MAP_PRIVATE | MAP_ANONYMOUS;
uint8_t* mapping = (uint8_t*) mmap(NULL, tls_size, prot, flags, -1, 0);
if ( (void*) mapping == MAP_FAILED )
return errno;
// We'll put the struct pthread nicely aligned in the new mapping.
struct pthread* thread =
(struct pthread*) (mapping + tls_offset_pthread);
assert((((uintptr_t) thread) & (alignof(struct pthread)-1)) == 0);
// Let's put the thread-local storage just before the struct pthread.
uint8_t* tls = mapping + tls_offset_tls;
// We will now initialize the thread-local storage of the new thread.
memcpy(tls, self->uthread.tls_master_mmap, self->uthread.tls_master_size);
// We'll clean up the new struct pthread before initializing it.
memset(thread, 0, sizeof(struct pthread));
// Initialize the thread object.
thread->uthread.uthread_pointer = &thread->uthread;
thread->uthread.uthread_size = sizeof(struct pthread);
thread->uthread.uthread_flags = 0;
thread->uthread.tls_master_mmap = self->uthread.tls_master_mmap;
thread->uthread.tls_master_size = self->uthread.tls_master_size;
thread->uthread.tls_master_align = self->uthread.tls_master_align;
thread->uthread.tls_mmap = mapping;
thread->uthread.tls_size = tls_size;
thread->uthread.arg_mmap = self->uthread.arg_mmap;
thread->uthread.arg_size = self->uthread.arg_size;
thread->join_lock = PTHREAD_NORMAL_MUTEX_INITIALIZER_NP;
thread->join_lock.lock = 1 /* LOCKED_VALUE */;
thread->join_lock.type = PTHREAD_MUTEX_NORMAL;
thread->join_lock.owner = (unsigned long) thread;
thread->detach_lock = PTHREAD_NORMAL_MUTEX_INITIALIZER_NP;
thread->detach_state = attr->detach_state;
thread->entry_function = entry_function;
thread->entry_cookie = entry_cookie;
// Set up a stack for the new thread.
int stack_prot = PROT_READ | PROT_WRITE;
int stack_flags = MAP_PRIVATE | MAP_ANONYMOUS;
thread->uthread.stack_size = attr->stack_size;
thread->uthread.stack_mmap =
mmap(NULL, thread->uthread.stack_size, stack_prot, stack_flags, -1, 0);
if ( thread->uthread.stack_mmap == MAP_FAILED )
{
munmap(thread->uthread.tls_mmap, thread->uthread.tls_size);
return errno;
}
// Prepare the registers and initial stack for the new thread.
struct tfork regs;
setup_thread_state(thread, &regs);
memset(&regs.altstack, 0, sizeof(regs.altstack));
regs.altstack.ss_flags = SS_DISABLE;
sigprocmask(SIG_SETMASK, NULL, &regs.sigmask);
// Create a new thread with the requested state.
if ( tfork(SFTHREAD, &regs) < 0 )
{
munmap(thread->uthread.stack_mmap, thread->uthread.stack_size);
munmap(thread->uthread.tls_mmap, thread->uthread.tls_size);
return errno;
}
*thread_ptr = thread;
return 0;
}