[wasi-libc.git] / libc-top-half / musl / src / env / __init_tls.c

#define SYSCALL_NO_TLS 1
#include <elf.h>
#include <limits.h>
#include <sys/mman.h>
#include <string.h>
#include <stddef.h>
#include "pthread_impl.h"
#include "libc.h"
#include "atomic.h"
#include "syscall.h"

volatile int __thread_list_lock;

int __init_tp(void *p)
{
	pthread_t td = p;
	td->self = td;
	int r = __set_thread_area(TP_ADJ(p));
	if (r < 0) return -1;
	if (!r) libc.can_do_threads = 1;
	td->detach_state = DT_JOINABLE;
	td->tid = __syscall(SYS_set_tid_address, &__thread_list_lock);
	td->locale = &libc.global_locale;
	td->robust_list.head = &td->robust_list.head;
	td->sysinfo = __sysinfo;
	td->next = td->prev = td;
	return 0;
}

static struct builtin_tls {
	char c;
	struct pthread pt;
	void *space[16];
} builtin_tls[1];
#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)

static struct tls_module main_tls;

void *__copy_tls(unsigned char *mem)
{
	pthread_t td;
	struct tls_module *p;
	size_t i;
	uintptr_t *dtv;

#ifdef TLS_ABOVE_TP
	dtv = (uintptr_t*)(mem + libc.tls_size) - (libc.tls_cnt + 1);

	mem += -((uintptr_t)mem + sizeof(struct pthread)) & (libc.tls_align-1);
	td = (pthread_t)mem;
	mem += sizeof(struct pthread);

	for (i=1, p=libc.tls_head; p; i++, p=p->next) {
		dtv[i] = (uintptr_t)(mem + p->offset) + DTP_OFFSET;
		memcpy(mem + p->offset, p->image, p->len);
	}
#else
	dtv = (uintptr_t *)mem;

	mem += libc.tls_size - sizeof(struct pthread);
	mem -= (uintptr_t)mem & (libc.tls_align-1);
	td = (pthread_t)mem;

	for (i=1, p=libc.tls_head; p; i++, p=p->next) {
		dtv[i] = (uintptr_t)(mem - p->offset) + DTP_OFFSET;
		memcpy(mem - p->offset, p->image, p->len);
	}
#endif
	dtv[0] = libc.tls_cnt;
	td->dtv = td->dtv_copy = dtv;
	return td;
}

#if ULONG_MAX == 0xffffffff
typedef Elf32_Phdr Phdr;
#else
typedef Elf64_Phdr Phdr;
#endif

extern weak hidden const size_t _DYNAMIC[];

static void static_init_tls(size_t *aux)
{
	unsigned char *p;
	size_t n;
	Phdr *phdr, *tls_phdr=0;
	size_t base = 0;
	void *mem;

	for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
		phdr = (void *)p;
		if (phdr->p_type == PT_PHDR)
			base = aux[AT_PHDR] - phdr->p_vaddr;
		if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
			base = (size_t)_DYNAMIC - phdr->p_vaddr;
		if (phdr->p_type == PT_TLS)
			tls_phdr = phdr;
		if (phdr->p_type == PT_GNU_STACK &&
		    phdr->p_memsz > __default_stacksize)
			__default_stacksize =
				phdr->p_memsz < DEFAULT_STACK_MAX ?
				phdr->p_memsz : DEFAULT_STACK_MAX;
	}

	if (tls_phdr) {
		main_tls.image = (void *)(base + tls_phdr->p_vaddr);
		main_tls.len = tls_phdr->p_filesz;
		main_tls.size = tls_phdr->p_memsz;
		main_tls.align = tls_phdr->p_align;
		libc.tls_cnt = 1;
		libc.tls_head = &main_tls;
	}

	main_tls.size += (-main_tls.size - (uintptr_t)main_tls.image)
		& (main_tls.align-1);
#ifdef TLS_ABOVE_TP
	main_tls.offset = GAP_ABOVE_TP;
	main_tls.offset += (-GAP_ABOVE_TP + (uintptr_t)main_tls.image)
		& (main_tls.align-1);
#else
	main_tls.offset = main_tls.size;
#endif
	if (main_tls.align < MIN_TLS_ALIGN) main_tls.align = MIN_TLS_ALIGN;

	libc.tls_align = main_tls.align;
	libc.tls_size = 2*sizeof(void *) + sizeof(struct pthread)
#ifdef TLS_ABOVE_TP
		+ main_tls.offset
#endif
		+ main_tls.size + main_tls.align
		+ MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;

	if (libc.tls_size > sizeof builtin_tls) {
#ifndef SYS_mmap2
#define SYS_mmap2 SYS_mmap
#endif
		mem = (void *)__syscall(
			SYS_mmap2,
			0, libc.tls_size, PROT_READ|PROT_WRITE,
			MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
		/* -4095...-1 cast to void * will crash on dereference anyway,
		 * so don't bloat the init code checking for error codes and
		 * explicitly calling a_crash(). */
	} else {
		mem = builtin_tls;
	}

	/* Failure to initialize thread pointer is always fatal. */
	if (__init_tp(__copy_tls(mem)) < 0)
		a_crash();
}

weak_alias(static_init_tls, __init_tls);
Commit	Line	Data
d4db3fa2	1	#define SYSCALL_NO_TLS 1
320054e8 DG	2	#include <elf.h>
	3	#include <limits.h>
	4	#include <sys/mman.h>
	5	#include <string.h>
	6	#include <stddef.h>
	7	#include "pthread_impl.h"
	8	#include "libc.h"
	9	#include "atomic.h"
	10	#include "syscall.h"
	11
f41256b6 DG	12	volatile int __thread_list_lock;
f41256b6 DG	13
320054e8 DG	14	int __init_tp(void *p)
	15	{
	16	pthread_t td = p;
	17	td->self = td;
	18	int r = __set_thread_area(TP_ADJ(p));
	19	if (r < 0) return -1;
	20	if (!r) libc.can_do_threads = 1;
	21	td->detach_state = DT_JOINABLE;
f41256b6	22	td->tid = __syscall(SYS_set_tid_address, &__thread_list_lock);
320054e8 DG	23	td->locale = &libc.global_locale;
320054e8 DG	24	td->robust_list.head = &td->robust_list.head;
d4db3fa2	25	td->sysinfo = __sysinfo;
f41256b6	26	td->next = td->prev = td;
320054e8 DG	27	return 0;
	28	}
	29
	30	static struct builtin_tls {
	31	char c;
	32	struct pthread pt;
	33	void *space[16];
	34	} builtin_tls[1];
	35	#define MIN_TLS_ALIGN offsetof(struct builtin_tls, pt)
	36
	37	static struct tls_module main_tls;
	38
	39	void __copy_tls(unsigned char mem)
	40	{
	41	pthread_t td;
	42	struct tls_module *p;
	43	size_t i;
	44	uintptr_t *dtv;
	45
	46	#ifdef TLS_ABOVE_TP
	47	dtv = (uintptr_t*)(mem + libc.tls_size) - (libc.tls_cnt + 1);
	48
	49	mem += -((uintptr_t)mem + sizeof(struct pthread)) & (libc.tls_align-1);
	50	td = (pthread_t)mem;
	51	mem += sizeof(struct pthread);
	52
	53	for (i=1, p=libc.tls_head; p; i++, p=p->next) {
	54	dtv[i] = (uintptr_t)(mem + p->offset) + DTP_OFFSET;
	55	memcpy(mem + p->offset, p->image, p->len);
	56	}
	57	#else
	58	dtv = (uintptr_t *)mem;
	59
	60	mem += libc.tls_size - sizeof(struct pthread);
	61	mem -= (uintptr_t)mem & (libc.tls_align-1);
	62	td = (pthread_t)mem;
	63
	64	for (i=1, p=libc.tls_head; p; i++, p=p->next) {
	65	dtv[i] = (uintptr_t)(mem - p->offset) + DTP_OFFSET;
	66	memcpy(mem - p->offset, p->image, p->len);
	67	}
	68	#endif
	69	dtv[0] = libc.tls_cnt;
	70	td->dtv = td->dtv_copy = dtv;
	71	return td;
	72	}
	73
	74	#if ULONG_MAX == 0xffffffff
	75	typedef Elf32_Phdr Phdr;
	76	#else
	77	typedef Elf64_Phdr Phdr;
	78	#endif
	79
	80	extern weak hidden const size_t _DYNAMIC[];
	81
	82	static void static_init_tls(size_t *aux)
	83	{
	84	unsigned char *p;
	85	size_t n;
	86	Phdr phdr, tls_phdr=0;
	87	size_t base = 0;
	88	void *mem;
	89
	90	for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
91	phdr = (void *)p;
92	if (phdr->p_type == PT_PHDR)
93	base = aux[AT_PHDR] - phdr->p_vaddr;
94	if (phdr->p_type == PT_DYNAMIC && _DYNAMIC)
95	base = (size_t)_DYNAMIC - phdr->p_vaddr;
96	if (phdr->p_type == PT_TLS)
97	tls_phdr = phdr;
98	if (phdr->p_type == PT_GNU_STACK &&
99	phdr->p_memsz > __default_stacksize)
100	__default_stacksize =
101	phdr->p_memsz < DEFAULT_STACK_MAX ?
102	phdr->p_memsz : DEFAULT_STACK_MAX;
103	}
104
105	if (tls_phdr) {
106	main_tls.image = (void *)(base + tls_phdr->p_vaddr);
107	main_tls.len = tls_phdr->p_filesz;
108	main_tls.size = tls_phdr->p_memsz;
109	main_tls.align = tls_phdr->p_align;
110	libc.tls_cnt = 1;
111	libc.tls_head = &main_tls;
112	}
113
114	main_tls.size += (-main_tls.size - (uintptr_t)main_tls.image)
115	& (main_tls.align-1);
116	#ifdef TLS_ABOVE_TP
117	main_tls.offset = GAP_ABOVE_TP;
d4db3fa2 DG	118	main_tls.offset += (-GAP_ABOVE_TP + (uintptr_t)main_tls.image)
d4db3fa2 DG	119	& (main_tls.align-1);
320054e8 DG	120	#else
	121	main_tls.offset = main_tls.size;
	122	#endif
	123	if (main_tls.align < MIN_TLS_ALIGN) main_tls.align = MIN_TLS_ALIGN;
	124
	125	libc.tls_align = main_tls.align;
	126	libc.tls_size = 2sizeof(void ) + sizeof(struct pthread)
	127	#ifdef TLS_ABOVE_TP
	128	+ main_tls.offset
	129	#endif
	130	+ main_tls.size + main_tls.align
	131	+ MIN_TLS_ALIGN-1 & -MIN_TLS_ALIGN;
	132
	133	if (libc.tls_size > sizeof builtin_tls) {
	134	#ifndef SYS_mmap2
	135	#define SYS_mmap2 SYS_mmap
	136	#endif
	137	mem = (void *)__syscall(
	138	SYS_mmap2,
	139	0, libc.tls_size, PROT_READ\|PROT_WRITE,
	140	MAP_ANONYMOUS\|MAP_PRIVATE, -1, 0);
	141	/* -4095...-1 cast to void * will crash on dereference anyway,
	142	* so don't bloat the init code checking for error codes and
	143	* explicitly calling a_crash(). */
	144	} else {
	145	mem = builtin_tls;
	146	}
	147
	148	/* Failure to initialize thread pointer is always fatal. */
	149	if (__init_tp(__copy_tls(mem)) < 0)
	150	a_crash();
	151	}
	152
	153	weak_alias(static_init_tls, __init_tls);