Switch pthread_create over to __bionic_clone.
Bug: 8206355
Bug: 11693195
Change-Id: I04aadbc36c87e1b7e33324b9a930a1e441fbfed6
diff --git a/libc/arch-arm/bionic/_exit_with_stack_teardown.S b/libc/arch-arm/bionic/_exit_with_stack_teardown.S
index c430edb..0d97f06 100644
--- a/libc/arch-arm/bionic/_exit_with_stack_teardown.S
+++ b/libc/arch-arm/bionic/_exit_with_stack_teardown.S
@@ -33,12 +33,11 @@
ENTRY(_exit_with_stack_teardown)
mov lr, r2
ldr r7, =__NR_munmap
- swi #0 // the stack is destroyed by this call
+ swi #0
+ // If munmap failed, we ignore the failure and exit anyway.
+
mov r0, lr
ldr r7, =__NR_exit
swi #0
-
- // exit() should never return, cause a crash if it does
- mov r0, #0
- ldr r0, [r0]
+ // The exit syscall does not return.
END(_exit_with_stack_teardown)
diff --git a/libc/arch-arm/bionic/clone.S b/libc/arch-arm/bionic/clone.S
index 3556b8e..0782abe 100644
--- a/libc/arch-arm/bionic/clone.S
+++ b/libc/arch-arm/bionic/clone.S
@@ -28,53 +28,7 @@
#include <private/bionic_asm.h>
-// int __pthread_clone(void* (*fn)(void*), void* child_stack, int flags, void* arg);
-ENTRY(__pthread_clone)
- # Push 'fn' and 'arg' onto 'child_stack'.
- stmdb r1!, {r0, r3}
-
- # The sys_clone system call only takes two arguments: 'flags' and 'child_stack'.
- # 'child_stack' is already in r1, but we need to move 'flags' into position.
- mov r0, r2
-
- # System call.
- mov ip, r7
- ldr r7, =__NR_clone
- swi #0
-
- # Child?
- movs r0, r0
- beq 1f
-
- # Parent.
- mov r7, ip
- cmn r0, #(MAX_ERRNO + 1)
- bxls lr
- neg r0, r0
- b __set_errno
-
-1: # Child.
- # Pop 'fn' and 'arg' back off the stack and call __thread_entry.
- pop {r0, r1}
- # __thread_entry also needs our stack pointer.
- mov r2, sp
- b __thread_entry
-END(__pthread_clone)
-
-
- #
- # This function is defined as:
- #
- # pid_t __bionic_clone( int flags, void *child_stack,
- # pid_t *pid, void *tls, pid_t *ctid,
- # int (*fn)(void *), void* arg );
- #
- # NOTE: This is not the same signature as the glibc
- # __clone function. Placing 'fn' and 'arg'
- # at the end of the parameter list makes the
- # implementation much simpler.
- #
-
+// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
ENTRY(__bionic_clone)
mov ip, sp
.save {r4, r5, r6, r7}
diff --git a/libc/arch-mips/bionic/_exit_with_stack_teardown.S b/libc/arch-mips/bionic/_exit_with_stack_teardown.S
index 8351e2e..9cab52b 100644
--- a/libc/arch-mips/bionic/_exit_with_stack_teardown.S
+++ b/libc/arch-mips/bionic/_exit_with_stack_teardown.S
@@ -30,7 +30,7 @@
.text
-// void _exit_with_stack_teardown(void * stackBase, size_t stackSize, int status)
+// void _exit_with_stack_teardown(void* stackBase, size_t stackSize, int status)
.type _exit_with_stack_teardown, @function
.global _exit_with_stack_teardown
@@ -40,12 +40,11 @@
move $s0,$a2 /* preserve status for exit() call */
li $v0,__NR_munmap
- syscall /* the stack is destroyed by this call */
+ syscall
+ // If munmap failed, we ignore the failure and exit anyway.
+
move $a0,$s0
li $v0,__NR_exit
syscall
-
- /* exit() should never return, cause a crash if it does */
- move $a0,$0
- lw $a0,($a0)
+ // The exit syscall does not return.
.end _exit_with_stack_teardown
diff --git a/libc/arch-mips/bionic/clone.S b/libc/arch-mips/bionic/clone.S
index 94e18a2..8970b6e 100644
--- a/libc/arch-mips/bionic/clone.S
+++ b/libc/arch-mips/bionic/clone.S
@@ -30,78 +30,7 @@
#include <linux/errno.h>
#include <linux/sched.h>
- .text
- .type __pthread_clone, @function
- .global __pthread_clone
- .align 4
- .ent __pthread_clone
-
-/*
- * int __pthread_clone(void* (*fn)(void*), void *child_stack,
- * int flags, void *arg);
- */
-
-__pthread_clone:
- .set noreorder
- .cpload $t9
- .set reorder
-
- # set up child stack
- subu $a1,16
- sw $a0,0($a1) # fn
- sw $a3,4($a1) # arg
-# sw $a1+16,8($a1) # tls
-
- /*
- * int sys_clone(int flags, void *child_stack, int *parent_tidptr,
- * struct user_desc *newtls, int *child_tidptr);
- */
-
- move $a0,$a2 # flags
-# move $a1,$a1 # child_stack
- move $a2,$0 # parent_tidptr
- move $a3,$0 # user_desc
- and $a0,~(CLONE_CHILD_SETTID | CLONE_CHILD_CLEARTID)
- # make sure the kernel doesn't access child_tidptr
-
- li $v0,__NR_clone
- syscall
-
- bnez $a3,.L__error
-
- beqz $v0,.L__thread_start
-
- j $ra
-
-.L__thread_start:
- lw $a0,0($sp) # fn
- lw $a1,4($sp) # arg
- addu $a2,$sp,16 # tls
-
- # void __thread_entry(void* (*func)(void*), void *arg, void *tls)
- la $t9, __thread_entry
- j $t9
-
-.L__error:
- move $a0,$v0
- la $t9,__set_errno
- j $t9
-
- .end __pthread_clone
-
-
- #
- # This function is defined as:
- #
- # pid_t __bionic_clone( int flags, void *child_stack,
- # pid_t *pid, void *tls, pid_t *ctid,
- # int (*fn)(void *), void* arg );
- #
- # NOTE: This is not the same signature than the GLibc
- # __clone function here !! Placing 'fn' and 'arg'
- # at the end of the parameter list makes the
- # implementation much simpler.
- #
+// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
.text
.type __bionic_clone, @function
.global __bionic_clone
diff --git a/libc/arch-x86/bionic/_exit_with_stack_teardown.S b/libc/arch-x86/bionic/_exit_with_stack_teardown.S
index 1c6d48a..9128f10 100644
--- a/libc/arch-x86/bionic/_exit_with_stack_teardown.S
+++ b/libc/arch-x86/bionic/_exit_with_stack_teardown.S
@@ -6,17 +6,15 @@
// We can trash %ebx here since this call should never return.
// We can also take advantage of the fact that the linux syscall trap
// handler saves all the registers, so we don't need a stack to keep
- // the status argument for exit while doing the munmap */
+ // the status argument for exit while doing the munmap.
mov 4(%esp), %ebx // stackBase
mov 8(%esp), %ecx // stackSize
mov $__NR_munmap, %eax
int $0x80
-
// If munmap failed, we ignore the failure and exit anyway.
mov %edx, %ebx // status
movl $__NR_exit, %eax
int $0x80
-
// The exit syscall does not return.
END(_exit_with_stack_teardown)
diff --git a/libc/arch-x86/bionic/clone.S b/libc/arch-x86/bionic/clone.S
index 457cb4a..eb9f545 100644
--- a/libc/arch-x86/bionic/clone.S
+++ b/libc/arch-x86/bionic/clone.S
@@ -1,68 +1,7 @@
#include <asm/unistd.h>
#include <machine/asm.h>
-// int __pthread_clone(void* (*fn)(void*), void* tls, int flags, void* arg);
-ENTRY(__pthread_clone)
- pushl %ebx
- pushl %ecx
- movl 16(%esp), %ecx
-
- # save tls
- movl %ecx, %ebx
- # 16-byte alignment on child stack
- andl $~15, %ecx
-
- # insert arguments onto the child stack
- movl 12(%esp), %eax
- movl %eax, -16(%ecx)
- movl 24(%esp), %eax
- movl %eax, -12(%ecx)
- movl %ebx, -8(%ecx)
-
- subl $16, %ecx
- movl 20(%esp), %ebx
-
- # make system call
- movl $__NR_clone, %eax
- int $0x80
-
- cmpl $0, %eax
- je pc_child
- jg pc_parent
-
- # an error occurred, set errno and return -1
- negl %eax
- pushl %eax
- call __set_errno
- addl $4, %esp
- orl $-1, %eax
- jmp pc_return
-
-pc_child:
- # we're in the child thread now, call __thread_entry
- # with the appropriate arguments on the child stack
- # we already placed most of them
- call __thread_entry
- hlt
-
-pc_parent:
- # we're the parent; nothing to do.
-pc_return:
- popl %ecx
- popl %ebx
- ret
-END(__pthread_clone)
-
-
-/*
- * int __bionic_clone(unsigned long clone_flags,
- * void* newsp,
- * int *parent_tidptr,
- * void *new_tls,
- * int *child_tidptr,
- * int (*fn)(void *),
- * void *arg);
- */
+// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
ENTRY(__bionic_clone)
pushl %ebx
pushl %esi
diff --git a/libc/arch-x86_64/bionic/_exit_with_stack_teardown.S b/libc/arch-x86_64/bionic/_exit_with_stack_teardown.S
index a09babe..eca3b68 100644
--- a/libc/arch-x86_64/bionic/_exit_with_stack_teardown.S
+++ b/libc/arch-x86_64/bionic/_exit_with_stack_teardown.S
@@ -36,12 +36,10 @@
// the status argument for exit(2) while doing the munmap(2).
mov $__NR_munmap, %eax
syscall
-
- // If munmap failed, ignore the failure and exit anyway.
+ // If munmap failed, we ignore the failure and exit anyway.
mov %rdx, %rdi // status
mov $__NR_exit, %eax
syscall
-
// The exit syscall does not return.
END(_exit_with_stack_teardown)
diff --git a/libc/arch-x86_64/bionic/clone.S b/libc/arch-x86_64/bionic/clone.S
index 7511e86..b37416b 100644
--- a/libc/arch-x86_64/bionic/clone.S
+++ b/libc/arch-x86_64/bionic/clone.S
@@ -29,53 +29,7 @@
#include <asm/unistd.h>
#include <machine/asm.h>
-// int __pthread_clone(void* (*fn)(void*), void* tls, int flags, void* arg);
-ENTRY(__pthread_clone)
- # Save tls.
- movq %rsi, %r11
- # Enforce 16-byte alignment for child stack.
- andq $~15, %rsi
-
- # Copy 'fn', 'arg', and 'tls' onto the child stack.
- movq %rdi, -32(%rsi) # fn
- movq %rcx, -24(%rsi) # arg
- movq %r11, -16(%rsi) # tls
- subq $32, %rsi
-
- movq %rdx, %rdi
- movl $__NR_clone, %eax
- syscall
- testl %eax, %eax
- jns 1f
-
- # An error occurred, set errno and return -1.
- negl %eax
- movl %eax, %edi
- call __set_errno
- orl $-1, %eax
- jmp 2f
-1:
- jnz 2f
-
- # We're in the child now, so call __thread_entry
- # with the arguments from the child stack moved into
- # the appropriate registers. We avoid pop here to keep
- # the required 16-byte stack alignment.
- movq (%rsp), %rdi # fn
- movq 8(%rsp), %rsi # arg
- movq 16(%rsp), %rdx # tls
- call __thread_entry
- hlt
-2:
- ret
-
-// int __bionic_clone(unsigned long clone_flags,
-// void* new_sp,
-// int* parent_tid_ptr,
-// void* new_tls,
-// int* child_tid_ptr,
-// int (*fn)(void*),
-// void* arg);
+// pid_t __bionic_clone(int flags, void* child_stack, pid_t* parent_tid, void* tls, pid_t* child_tid, int (*fn)(void*), void* arg);
ENTRY(__bionic_clone)
# Enforce 16-byte alignment for child stack.
andq $~15, %rsi
diff --git a/libc/bionic/__thread_entry.cpp b/libc/bionic/__thread_entry.cpp
index 8300a64..3505f8b 100644
--- a/libc/bionic/__thread_entry.cpp
+++ b/libc/bionic/__thread_entry.cpp
@@ -32,26 +32,28 @@
#include "private/bionic_tls.h"
-// This trampoline is called from the assembly _pthread_clone function.
-// Our 'tls' and __pthread_clone's 'child_stack' are one and the same, just growing in
-// opposite directions.
-extern "C" void __thread_entry(void* (*func)(void*), void* arg, void** tls) {
+// This trampoline is called from the assembly __bionic_clone function.
+int __thread_entry(void* arg) {
+ pthread_internal_t* thread = reinterpret_cast<pthread_internal_t*>(arg);
+
// Wait for our creating thread to release us. This lets it have time to
// notify gdb about this thread before we start doing anything.
// This also provides the memory barrier needed to ensure that all memory
// accesses previously made by the creating thread are visible to us.
- pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
+ pthread_mutex_t* start_mutex = (pthread_mutex_t*) &thread->tls[TLS_SLOT_START_MUTEX];
pthread_mutex_lock(start_mutex);
pthread_mutex_destroy(start_mutex);
- pthread_internal_t* thread = (pthread_internal_t*) tls[TLS_SLOT_THREAD_ID];
- thread->tls = tls;
__init_tls(thread);
+ __init_alternate_signal_stack(thread);
+
if ((thread->internal_flags & PTHREAD_INTERNAL_FLAG_THREAD_INIT_FAILED) != 0) {
pthread_exit(NULL);
}
- void* result = func(arg);
+ void* result = thread->start_routine(thread->start_routine_arg);
pthread_exit(result);
+
+ return 0;
}
diff --git a/libc/bionic/bionic_clone.c b/libc/bionic/bionic_clone.c
index 8a17e13..518d996 100644
--- a/libc/bionic/bionic_clone.c
+++ b/libc/bionic/bionic_clone.c
@@ -31,14 +31,7 @@
#include <stdarg.h>
#include <stdio.h>
-extern int __bionic_clone(unsigned long clone_flags,
- void* newsp,
- int *parent_tidptr,
- void *new_tls,
- int *child_tidptr,
- int (*fn)(void *),
- void *arg);
-
+extern pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
extern void __exit(int status);
/* this function is called from the __bionic_clone
diff --git a/libc/bionic/libc_init_common.cpp b/libc/bionic/libc_init_common.cpp
index f88a26d..3e092ae 100644
--- a/libc/bionic/libc_init_common.cpp
+++ b/libc/bionic/libc_init_common.cpp
@@ -49,6 +49,7 @@
extern "C" abort_msg_t** __abort_message_ptr;
extern "C" uintptr_t __get_sp(void);
extern "C" int __system_properties_init(void);
+extern "C" int __set_tls(void* ptr);
// Not public, but well-known in the BSDs.
const char* __progname;
@@ -96,7 +97,10 @@
pthread_attr_setstack(&thread.attr, (void*) stack_bottom, stack_size);
_init_thread(&thread, false);
__init_tls(&thread);
+ __set_tls(thread.tls);
tls[TLS_SLOT_BIONIC_PREINIT] = &args;
+
+ __init_alternate_signal_stack(&thread);
}
void __libc_init_common(KernelArgumentBlock& args) {
diff --git a/libc/bionic/pthread_create.cpp b/libc/bionic/pthread_create.cpp
index 2153310..386e8d1 100644
--- a/libc/bionic/pthread_create.cpp
+++ b/libc/bionic/pthread_create.cpp
@@ -40,7 +40,7 @@
#include "private/ErrnoRestorer.h"
#include "private/ScopedPthreadMutexLocker.h"
-extern "C" int __pthread_clone(void* (*fn)(void*), void* child_stack, int flags, void* arg);
+extern "C" pid_t __bionic_clone(uint32_t flags, void* child_stack, int* parent_tid, void* tls, int* child_tid, int (*fn)(void*), void* arg);
#ifdef __i386__
#define ATTRIBUTES __attribute__((noinline)) __attribute__((fastcall))
@@ -50,15 +50,14 @@
extern "C" void ATTRIBUTES _thread_created_hook(pid_t thread_id);
-extern "C" int __set_tls(void* ptr);
-
static pthread_mutex_t gPthreadStackCreationLock = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t gDebuggerNotificationLock = PTHREAD_MUTEX_INITIALIZER;
+// This code is used both by each new pthread and the code that initializes the main thread.
void __init_tls(pthread_internal_t* thread) {
- // Zero-initialize all the slots.
- for (size_t i = 0; i < BIONIC_TLS_SLOTS; ++i) {
+ // Zero-initialize all the slots after TLS_SLOT_SELF and TLS_SLOT_THREAD_ID.
+ for (size_t i = TLS_SLOT_ERRNO; i < BIONIC_TLS_SLOTS; ++i) {
thread->tls[i] = NULL;
}
@@ -67,11 +66,10 @@
thread->tls[TLS_SLOT_THREAD_ID] = thread;
// GCC looks in the TLS for the stack guard on x86, so copy it there from our global.
thread->tls[TLS_SLOT_STACK_GUARD] = (void*) __stack_chk_guard;
+}
- __set_tls(thread->tls);
-
+void __init_alternate_signal_stack(pthread_internal_t* thread) {
// Create and set an alternate signal stack.
- // This must happen after __set_tls, in case a system call fails and tries to set errno.
stack_t ss;
ss.ss_sp = mmap(NULL, SIGSTKSZ, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, 0, 0);
if (ss.ss_sp != MAP_FAILED) {
@@ -181,24 +179,26 @@
// The child stack is the same address, just growing in the opposite direction.
// At offsets >= 0, we have the TLS slots.
// At offsets < 0, we have the child stack.
- void** tls = (void**)((uint8_t*)(thread->attr.stack_base) + thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
- void* child_stack = tls;
+ thread->tls = (void**)((uint8_t*)(thread->attr.stack_base) + thread->attr.stack_size - BIONIC_TLS_SLOTS * sizeof(void*));
+ void* child_stack = thread->tls;
- // Create a mutex for the thread in TLS_SLOT_SELF to wait on once it starts so we can keep
+ // Create a mutex for the thread in TLS to wait on once it starts so we can keep
// it from doing anything until after we notify the debugger about it
//
// This also provides the memory barrier we need to ensure that all
// memory accesses previously performed by this thread are visible to
// the new thread.
- pthread_mutex_t* start_mutex = (pthread_mutex_t*) &tls[TLS_SLOT_SELF];
+ pthread_mutex_t* start_mutex = (pthread_mutex_t*) &thread->tls[TLS_SLOT_START_MUTEX];
pthread_mutex_init(start_mutex, NULL);
ScopedPthreadMutexLocker start_locker(start_mutex);
- tls[TLS_SLOT_THREAD_ID] = thread;
+ thread->tls[TLS_SLOT_THREAD_ID] = thread;
- int flags = CLONE_FILES | CLONE_FS | CLONE_VM | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM;
+ thread->start_routine = start_routine;
+ thread->start_routine_arg = arg;
- int tid = __pthread_clone(start_routine, child_stack, flags, arg);
+ int flags = CLONE_VM | CLONE_FS | CLONE_FILES | CLONE_SIGHAND | CLONE_THREAD | CLONE_SYSVSEM | CLONE_SETTLS;
+ int tid = __bionic_clone(flags, child_stack, NULL, thread->tls, NULL, __thread_entry, thread);
if (tid < 0) {
int clone_errno = errno;
if ((thread->attr.flags & PTHREAD_ATTR_FLAG_USER_ALLOCATED_STACK) == 0) {
diff --git a/libc/bionic/pthread_internal.h b/libc/bionic/pthread_internal.h
index 8cca83a..52cfbce 100644
--- a/libc/bionic/pthread_internal.h
+++ b/libc/bionic/pthread_internal.h
@@ -42,6 +42,9 @@
__pthread_cleanup_t* cleanup_stack;
void** tls; /* thread-local storage area */
+ void* (*start_routine)(void*);
+ void* start_routine_arg;
+
void* alternate_signal_stack;
/*
@@ -52,8 +55,12 @@
char dlerror_buffer[__BIONIC_DLERROR_BUFFER_SIZE];
};
+extern "C" {
+ __LIBC_HIDDEN__ int __thread_entry(void* arg); // Called from assembler.
+}
__LIBC_HIDDEN__ int _init_thread(pthread_internal_t* thread, bool add_to_thread_list);
__LIBC_HIDDEN__ void __init_tls(pthread_internal_t* thread);
+__LIBC_HIDDEN__ void __init_alternate_signal_stack(pthread_internal_t*);
__LIBC_HIDDEN__ void _pthread_internal_add(pthread_internal_t* thread);
__LIBC_HIDDEN__ pthread_internal_t* __get_thread(void);
diff --git a/libc/private/bionic_tls.h b/libc/private/bionic_tls.h
index a14bd3c..094c71c 100644
--- a/libc/private/bionic_tls.h
+++ b/libc/private/bionic_tls.h
@@ -51,6 +51,9 @@
TLS_SLOT_THREAD_ID,
TLS_SLOT_ERRNO,
+ /* This slot is used when starting a new thread, before any code that needs errno runs. */
+ TLS_SLOT_START_MUTEX = TLS_SLOT_ERRNO,
+
/* These two aren't used by bionic itself, but allow the graphics code to
* access TLS directly rather than using the pthread API. */
TLS_SLOT_OPENGL_API = 3,