From adf29fcdda3953717ffb5114811d29ebcb22d109 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Axel=20D=C3=B6rfler?= Date: Tue, 12 Oct 2004 03:52:53 +0000 Subject: [PATCH] Removed the broken arch_thread::current_iframe field and switched to the same mechanism as NewOS, ie. using the iframe "stack" pointer (using the new i386_get_current_iframe() function). Implemented fork() support functions arch_{store|restore}_fork_frame(). git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9292 a95241bf-73f2-0310-859d-f6bbb57e9c96 --- src/kernel/core/arch/x86/arch_thread.c | 102 ++++++++++++++++++++----- 1 file changed, 85 insertions(+), 17 deletions(-) diff --git a/src/kernel/core/arch/x86/arch_thread.c b/src/kernel/core/arch/x86/arch_thread.c index f04f39f81a..98c706f609 100755 --- a/src/kernel/core/arch/x86/arch_thread.c +++ b/src/kernel/core/arch/x86/arch_thread.c @@ -1,6 +1,6 @@ /* -** Copyright 2002-2004, The OpenBeOS Team. All rights reserved. -** Distributed under the terms of the OpenBeOS License. +** Copyright 2002-2004, The Haiku Team. All rights reserved. +** Distributed under the terms of the Haiku License. ** ** Copyright 2001, Travis Geiselbrecht. All rights reserved. ** Distributed under the terms of the NewOS License. @@ -25,6 +25,7 @@ // from arch_interrupts.S extern void i386_stack_init(struct farcall *interrupt_stack_offset); +extern void i386_restore_frame_from_syscall(struct iframe frame); void @@ -43,6 +44,32 @@ i386_pop_iframe(struct thread *thread) } +/** Returns the current iframe structure of the running thread. + * This function must only be called in a context where it's actually + * sure that such iframe exists; ie. from syscalls, but usually not + * from standard kernel threads. + */ + +static struct iframe * +i386_get_current_iframe(void) +{ + struct thread *thread = thread_get_current_thread(); + + ASSERT(thread->arch_info.iframe_ptr >= 0); + return thread->arch_info.iframes[thread->arch_info.iframe_ptr - 1]; +} + + +static inline uint32 +get_fs_register(void) +{ + uint32 fs; + + asm("movl %%fs,%0" : "=r" (fs)); + return fs; +} + + static inline void set_fs_register(uint32 segment) { @@ -85,9 +112,9 @@ arch_thread_init_thread_struct(struct thread *t) int arch_thread_init_kthread_stack(struct thread *t, int (*start_func)(void), void (*entry_func)(void), void (*exit_func)(void)) { - unsigned int *kstack = (unsigned int *)t->kernel_stack_base; - unsigned int kstack_size = KSTACK_SIZE; - unsigned int *kstack_top = kstack + kstack_size / sizeof(unsigned int); + addr_t *kstack = (addr_t *)t->kernel_stack_base; + addr_t kstack_size = KSTACK_SIZE; + addr_t *kstack_top = kstack + kstack_size / sizeof(addr_t); int i; TRACE(("arch_thread_initialize_kthread_stack: kstack 0x%p, start_func 0x%p, entry_func 0x%p\n", @@ -120,7 +147,7 @@ arch_thread_init_kthread_stack(struct thread *t, int (*start_func)(void), void ( // save the stack position t->arch_info.current_stack.esp = kstack_top; - t->arch_info.current_stack.ss = (int *)KERNEL_DATA_SEG; + t->arch_info.current_stack.ss = (addr_t *)KERNEL_DATA_SEG; return 0; } @@ -249,7 +276,7 @@ arch_thread_enter_uspace(struct thread *t, addr_t entry, void *args1, void *args status_t arch_setup_signal_frame(struct thread *t, struct sigaction *sa, int sig, int sig_mask) { - struct iframe *frame = t->arch_info.current_iframe; + struct iframe *frame = i386_get_current_iframe(); uint32 *stack_ptr = (uint32 *)frame->user_esp; uint32 *code_ptr; uint32 *regs_ptr; @@ -264,6 +291,7 @@ arch_setup_signal_frame(struct thread *t, struct sigaction *sa, int sig, int sig frame->eax = frame->orig_eax; frame->edx = frame->orig_edx; frame->eip -= 2; + // undos the "int $99" syscall interrupt (so that it'll be called again) } } @@ -323,14 +351,12 @@ int64 arch_restore_signal_frame(void) { struct thread *t = thread_get_current_thread(); - struct iframe *frame; + struct iframe *frame = i386_get_current_iframe(); uint32 *stack; struct vregs *regs; - + TRACE(("### arch_restore_signal_frame: entry\n")); - - frame = t->arch_info.current_iframe; - + stack = (uint32 *)frame->user_esp; t->sig_block_mask = stack[0]; regs = (struct vregs *)stack[1]; @@ -345,13 +371,13 @@ arch_restore_signal_frame(void) frame->edi = regs->_reserved_2[0]; frame->esi = regs->_reserved_2[1]; frame->ebp = regs->_reserved_2[2]; - + i386_frstor((void *)(®s->xregs)); - + TRACE(("### arch_restore_signal_frame: exit\n")); - + frame->orig_eax = -1; /* disable syscall checks */ - + return (int64)frame->eax | ((int64)frame->edx << 32); } @@ -359,7 +385,7 @@ arch_restore_signal_frame(void) void arch_check_syscall_restart(struct thread *t) { - struct iframe *frame = t->arch_info.current_iframe; + struct iframe *frame = i386_get_current_iframe(); if ((status_t)frame->orig_eax >= 0 && (status_t)frame->eax == EINTR) { frame->eax = frame->orig_eax; @@ -368,3 +394,45 @@ arch_check_syscall_restart(struct thread *t) } } + +/** Saves everything needed to restore the frame in the child fork in the + * arch_fork_arg structure to be passed to arch_restore_fork_frame(). + * Also makes sure to return the right value. + */ + +void +arch_store_fork_frame(struct arch_fork_arg *arg) +{ + struct iframe *frame = i386_get_current_iframe(); + + // we need to copy the threads current iframe + arg->iframe = *frame; + + // we also want fork() to return 0 for the child + arg->iframe.eax = 0; +} + + +/** Restores the frame from a forked team as specified by the provided + * arch_fork_arg structure. + * Needs to be called from within the child team, ie. instead of + * arch_thread_enter_uspace() as thread "starter". + * This function does not return to the caller, but will enter userland + * in the child team at the same position where the parent team left of. + */ + +void +arch_restore_fork_frame(struct arch_fork_arg *arg) +{ + struct thread *thread = thread_get_current_thread(); + + i386_set_tss_and_kstack(thread->kernel_stack_base + KSTACK_SIZE); + + // set the CPU dependent GDT entry for TLS (set the current %fs register) + set_tls_context(thread); + + // patch up %fs register of the frame + arg->iframe.fs = get_fs_register(); + + i386_restore_frame_from_syscall(arg->iframe); +}