X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;ds=sidebyside;f=src%2Fenv%2F__init_tls.c;h=89d081ef50af32bcf7092012d033fe8664730ace;hb=805698401dbac7ce3079fa97eaad5ba0508377f4;hp=6b3cd28bb03699d6a71e32a9de276398389779c4;hpb=6a2eaa3c5bbb8cc272cf6a4b7a9766a89e9b2c61;p=musl

diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
index 6b3cd28b..89d081ef 100644
--- a/src/env/__init_tls.c
+++ b/src/env/__init_tls.c
@@ -1,27 +1,61 @@
 #include <elf.h>
 #include <limits.h>
+#include <sys/mman.h>
+#include <string.h>
 #include "pthread_impl.h"
 #include "libc.h"
 #include "atomic.h"
+#include "syscall.h"
+
+int __init_tp(void *p)
+{
+	pthread_t td = p;
+	td->self = td;
+	if (__set_thread_area(TP_ADJ(p)) < 0)
+		return -1;
+	td->tid = td->pid = __syscall(SYS_set_tid_address, &td->tid);
+	td->errno_ptr = &td->errno_val;
+	/* Currently, both of these predicates depend in the same thing:
+	 * successful initialization of the thread pointer. However, in
+	 * the future, we may support setups where setting the thread
+	 * pointer is possible but threads other than the main thread
+	 * cannot work, so it's best to keep the predicates separate. */
+	libc.has_thread_pointer = 1;
+	libc.can_do_threads = 1;
+	return 0;
+}
 
 #ifndef SHARED
 
-static void *image;
-static size_t len, size, align;
+static long long builtin_tls[(sizeof(struct pthread) + 64)/sizeof(long long)];
+
+struct tls_image {
+	void *image;
+	size_t len, size, align;
+} __static_tls ATTR_LIBC_VISIBILITY;
+
+#define T __static_tls
 
 void *__copy_tls(unsigned char *mem)
 {
 	pthread_t td;
-	if (!image) return mem;
+	if (!T.image) return mem;
 	void **dtv = (void *)mem;
 	dtv[0] = (void *)1;
-	mem += __libc.tls_size - sizeof(struct pthread);
-	mem -= (uintptr_t)mem & (align-1);
+#ifdef TLS_ABOVE_TP
+	mem += sizeof(void *) * 2;
+	mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
 	td = (pthread_t)mem;
+	mem += sizeof(struct pthread);
+#else
+	mem += libc.tls_size - sizeof(struct pthread);
+	mem -= (uintptr_t)mem & (T.align-1);
+	td = (pthread_t)mem;
+	mem -= T.size;
+#endif
 	td->dtv = dtv;
-	mem -= size;
 	dtv[1] = mem;
-	memcpy(mem, image, len);
+	memcpy(mem, T.image, T.len);
 	return td;
 }
 
@@ -30,58 +64,61 @@ void *__tls_get_addr(size_t *v)
 	return (char *)__pthread_self()->dtv[1]+v[1];
 }
 
-static void *simple(void *p)
-{
-	*(void **)p = p;
-	return __set_thread_area(p) ? 0 : p;
-}
-
-weak_alias(simple, __install_initial_tls);
-
-void *__mmap(void *, size_t, int, int, int, off_t);
-
 #if ULONG_MAX == 0xffffffff
 typedef Elf32_Phdr Phdr;
 #else
 typedef Elf64_Phdr Phdr;
 #endif
 
-#define AUX_CNT 6
-
-void __init_tls(size_t *auxv)
+void __init_tls(size_t *aux)
 {
-	size_t i, aux[AUX_CNT] = { 0 };
-	unsigned char *p, *mem;
-	size_t n, d;
+	unsigned char *p;
+	size_t n;
 	Phdr *phdr, *tls_phdr=0;
 	size_t base = 0;
+	void *mem;
+
+	libc.tls_size = sizeof(struct pthread);
 
-	for (; auxv[0]; auxv+=2) if (auxv[0]<AUX_CNT) aux[auxv[0]] = auxv[1];
-	p = (void *)aux[AT_PHDR];
-	for (p=(void *)aux[AT_PHDR]; aux[AT_PHNUM]--; p+=aux[AT_PHENT]) {
+	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_TLS)
 			tls_phdr = phdr;
 	}
-	if (!tls_phdr) return;
 
-	image = (void *)(base + tls_phdr->p_vaddr);
-	len = tls_phdr->p_filesz;
-	size = tls_phdr->p_memsz;
-	align = tls_phdr->p_align;
+	if (tls_phdr) {
+		T.image = (void *)(base + tls_phdr->p_vaddr);
+		T.len = tls_phdr->p_filesz;
+		T.size = tls_phdr->p_memsz;
+		T.align = tls_phdr->p_align;
+	}
 
-	size += (-size - (uintptr_t)image) & (align-1);
-	if (align < 4*sizeof(size_t)) align = 4*sizeof(size_t);
+	T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
+	if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
 
-	libc.tls_size = 2*sizeof(void *)+size+align+sizeof(struct pthread);
+	libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
 
-	mem = __mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
-		MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
-	if (mem == MAP_FAILED) a_crash();
+	if (libc.tls_size > sizeof builtin_tls) {
+		mem = (void *)__syscall(
+#ifdef SYS_mmap2
+			SYS_mmap2,
+#else
+			SYS_mmap,
+#endif
+			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;
+	}
 
-	if (!__install_initial_tls(__copy_tls(mem))) a_crash();
+	/* Failure to initialize thread pointer is fatal if TLS is used. */
+	if (__init_tp(__copy_tls(mem)) < 0 && tls_phdr)
+		a_crash();
 }
 #else
 void __init_tls(size_t *auxv) { }