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127 lines
3.0 KiB
127 lines
3.0 KiB
#include <elf.h>
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#include <limits.h>
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#include <sys/mman.h>
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#include <string.h>
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#include "pthread_impl.h"
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#include "libc.h"
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#include "atomic.h"
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#include "syscall.h"
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int __init_tp(void *p)
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{
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pthread_t td = p;
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td->self = td;
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if (__set_thread_area(TP_ADJ(p)) < 0)
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return -1;
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td->tid = td->pid = __syscall(SYS_set_tid_address, &td->tid);
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td->errno_ptr = &td->errno_val;
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/* Currently, both of these predicates depend in the same thing:
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* successful initialization of the thread pointer. However, in
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* the future, we may support setups where setting the thread
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* pointer is possible but threads other than the main thread
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* cannot work, so it's best to keep the predicates separate. */
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libc.has_thread_pointer = 1;
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libc.can_do_threads = 1;
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return 0;
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}
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#ifndef SHARED
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static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
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struct tls_image {
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void *image;
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size_t len, size, align;
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} __static_tls ATTR_LIBC_VISIBILITY;
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#define T __static_tls
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void *__copy_tls(unsigned char *mem)
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{
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pthread_t td;
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if (!T.image) return mem;
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void **dtv = (void *)mem;
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dtv[0] = (void *)1;
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#ifdef TLS_ABOVE_TP
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mem += sizeof(void *) * 2;
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mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
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td = (pthread_t)mem;
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mem += sizeof(struct pthread);
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#else
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mem += libc.tls_size - sizeof(struct pthread);
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mem -= (uintptr_t)mem & (T.align-1);
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td = (pthread_t)mem;
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mem -= T.size;
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#endif
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td->dtv = dtv;
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dtv[1] = mem;
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memcpy(mem, T.image, T.len);
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return td;
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}
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void *__tls_get_addr(size_t *v)
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{
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return (char *)__pthread_self()->dtv[1]+v[1];
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}
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void *__mmap(void *, size_t, int, int, int, off_t);
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#if ULONG_MAX == 0xffffffff
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typedef Elf32_Phdr Phdr;
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#else
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typedef Elf64_Phdr Phdr;
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#endif
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void __init_tls(size_t *aux)
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{
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unsigned char *p;
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size_t n;
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Phdr *phdr, *tls_phdr=0;
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size_t base = 0;
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void *mem;
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libc.tls_size = sizeof(struct pthread);
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for (p=(void *)aux[AT_PHDR],n=aux[AT_PHNUM]; n; n--,p+=aux[AT_PHENT]) {
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phdr = (void *)p;
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if (phdr->p_type == PT_PHDR)
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base = aux[AT_PHDR] - phdr->p_vaddr;
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if (phdr->p_type == PT_TLS)
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tls_phdr = phdr;
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}
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if (tls_phdr) {
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T.image = (void *)(base + tls_phdr->p_vaddr);
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T.len = tls_phdr->p_filesz;
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T.size = tls_phdr->p_memsz;
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T.align = tls_phdr->p_align;
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}
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T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
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if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
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libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
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if (libc.tls_size > sizeof builtin_tls) {
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mem = (void *)__syscall(
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#ifdef SYS_mmap2
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SYS_mmap2,
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#else
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SYS_mmap,
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#endif
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0, libc.tls_size, PROT_READ|PROT_WRITE,
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MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
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/* -4095...-1 cast to void * will crash on dereference anyway,
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* so don't bloat the init code checking for error codes and
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* explicitly calling a_crash(). */
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} else {
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mem = builtin_tls;
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}
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/* Failure to initialize thread pointer is fatal if TLS is used. */
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if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
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a_crash();
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}
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#else
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void __init_tls(size_t *auxv) { }
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#endif
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