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Implemented new i386_restore_frame_from_syscall() function needed by fork().

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Added some comments.


git-svn-id: file:///srv/svn/repos/haiku/trunk/current@9290 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler
2004-10-12 03:47:09 +00:00
parent 8bf77a7332
commit 27d0a0aaff
1 changed files with 38 additions and 7 deletions
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src/kernel/core/arch/x86/arch_interrupts.S
+35 -4
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@@ -1,4 +1,7 @@
/* /*
** Copyright 2002-2004, The Haiku Team. All rights reserved.
** Distributed under the terms of the Haiku License.
**
** Copyright 2001, Travis Geiselbrecht. All rights reserved. ** Copyright 2001, Travis Geiselbrecht. All rights reserved.
** Copyright 2002, Michael Noisternig. All rights reserved. ** Copyright 2002, Michael Noisternig. All rights reserved.
** Distributed under the terms of the NewOS License. ** Distributed under the terms of the NewOS License.
@@ -105,8 +108,8 @@ int_bottom:
// custom stack -> copy registers to kernel stack and switch there // custom stack -> copy registers to kernel stack and switch there
custom_stack: custom_stack:
movl %dr3,%edx // get_current_thread movl %dr3,%edx // get current struct thread
movl %eax,%es movl %eax,%es // the iframe is on the wrong stack
addl _interrupt_stack_offset,%edx addl _interrupt_stack_offset,%edx
lss (%edx),%esp lss (%edx),%esp
movl %ebx,%ds movl %ebx,%ds
@@ -130,6 +133,7 @@ int_bottom:
_interrupt_stack_offset: _interrupt_stack_offset:
.long 0 .long 0
// this value will be maintained by the function below
// void i386_stack_init(struct farcall *interrupt_stack_offset) // void i386_stack_init(struct farcall *interrupt_stack_offset)
/* setup in arch_thread.c: arch_thread_init_thread_struct() */ /* setup in arch_thread.c: arch_thread_init_thread_struct() */
@@ -160,12 +164,39 @@ FUNCTION(i386_stack_switch):
popf popf
jmp *%edx jmp *%edx
/** Is copied to the signal stack call to restore the original frame when
* the signal handler exits.
* The copying code (in arch_thread.c::arch_setup_signal_frame()) copies
* everything between the i386_return_from_signal and i386_end_return_from_signal
* symbols.
*/
FUNCTION(i386_return_from_signal): FUNCTION(i386_return_from_signal):
addl $12, %esp // Flushes the 3 arguments to sa_handler addl $12, %esp // Flushes the 3 arguments to sa_handler
movl $SYSCALL_RESTORE_SIGNAL_FRAME, %eax // This syscall will restore the cpu context to the movl $SYSCALL_RESTORE_SIGNAL_FRAME, %eax
movl $0, %ecx // one existing before calling the signal handler // This syscall will restore the cpu context to the
// one existing before calling the signal handler
movl $0, %ecx
lea 4(%esp), %edx lea 4(%esp), %edx
int $99 int $99
ret ret
FUNCTION(i386_end_return_from_signal): FUNCTION(i386_end_return_from_signal):
/** void i386_restore_frame_from_syscall(struct iframe iframe);
* Pops the regs of the iframe from the stack to make it current and then
* return to userland.
*/
FUNCTION(i386_restore_frame_from_syscall):
add $4, %esp // make the iframe our current stack position (we don't need the
// return address anymore, as we will use the one of the frame)
pop %gs // recreate the frame environment
pop %fs
pop %es
pop %ds
popa
addl $16,%esp // ignore the vector, error code, and original eax/edx values
// (which contain the syscall number and argument pointer)
iret