X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/0cf90cca0c924622f3fee8d2a3fafa8238363dc6..bb793d5c6918efee6a86de442463a7c9aaa4ecdd:/lunaix-os/kernel/asm/x86/interrupt.S diff --git a/lunaix-os/kernel/asm/x86/interrupt.S b/lunaix-os/kernel/asm/x86/interrupt.S index c869db0..f308503 100644 --- a/lunaix-os/kernel/asm/x86/interrupt.S +++ b/lunaix-os/kernel/asm/x86/interrupt.S @@ -1,7 +1,10 @@ #define __ASM__ #include -#include +#include +#include #include +#include + #define __ASM_INTR_DIAGNOSIS #ifdef __ASM_INTR_DIAGNOSIS @@ -16,43 +19,25 @@ .section .bss .align 16 lo_tmp_stack: - .skip 128 + .skip 256 tmp_stack: +/* + This perhaps the ugliest part in the project. + It contains code to handle arbitrary depth of + nested interrupt and all those corner cases and + nasty gotchas. + + Be aware the twists, offsets and hidden dependencies! + +*/ + .section .text .global interrupt_wrapper interrupt_wrapper: - /* - Stack layout (layout of struct isr_param) - msa: [ss] > 76 - [esp] > 72 - eflags > 68 - cs > 64 - eip > 60 - err_code > 56 - vector > offset = 52 - [saved_prev_ctx] > offset = 0 - --- - esp - gs - fs - es - ds > offset = 7 * 4 = 28 + 4 - esi - ebp - edi - edx - ecx - ebx - eax - lsa: depth > offset = 0 - - las: Least Significant Address - msa: Most Significant Address - */ cld - subl $52, %esp + subl $4, %esp pushl %esp subl $16, %esp @@ -70,34 +55,38 @@ pushl %eax movl __current, %eax - movl 8(%eax), %eax + movl proc_intr_ctx(%eax), %eax incl %eax pushl %eax # nested intr: current depth - movl 116(%esp), %eax /* 取出 %cs */ + movl ics(%esp), %eax /* 取出 %cs */ andl $0x3, %eax /* 判断 RPL */ jz 1f - movw $KDATA_SEG, %ax /* 如果从用户模式转来，则切换至内核数据段 */ + /* crossing the user/kernel boundary */ + movw $KDATA_SEG, %ax movw %ax, %gs movw %ax, %fs movw %ax, %ds movw %ax, %es - # 保存用户栈顶指针。这是因为我们允许系统调用内进行上下文切换，而这样一来，我们就失去了用户栈的信息， - # 这样一来，就无法设置信号上下文。这主要是为了实现了pause()而做的准备 - movl __current, %eax + movl __current, %ebx - # 保存x87FPU的状态 - movl 68(%eax), %ebx - fxsave (%ebx) + # Save x87 context to user stack, rather than kernel's memory. + # XXX what will happen if we triggered a page fault during fxsave? + # FIXME can we remove this overhead? + movl iuesp(%esp), %eax + andl $stack_alignment, %eax + subl $512, %eax + fxsave (%eax) - movl 124(%esp), %ebx # 取出esp - movl %ebx, 60(%eax) # 存入__current->ustack_top + # 保存用户栈顶指针。因为我们允许同级中断的产生，所以需要该手段跟踪用户栈的地址。 + movl %eax, proc_ustack_top(%ebx) # 存入__current->ustack_top + /* kernel space same-level switch */ 1: movl %esp, %eax - andl $0xfffffff0, %esp + andl $stack_alignment, %esp subl $16, %esp movl %eax, (%esp) @@ -111,16 +100,21 @@ #ifdef __ASM_INTR_DIAGNOSIS movl %eax, (debug_resv + 8) - movl 48(%esp), %eax - movl 60(%eax), %eax + movl iesp(%esp), %eax + movl exeip(%eax), %eax movl %eax, (debug_resv + 4) # eip #endif - movl __current, %eax - movl 68(%eax), %eax - - test %eax, %eax # do we have stored x87 context? + + movl ics(%esp), %eax + andl $3, %eax jz 1f - fxrstor (%eax) + + movl __current, %eax + movl proc_ustack_top(%eax), %eax + test %eax, %eax + jz 1f + fxrstor (%eax) + 1: popl %eax # discard isr_param::depth popl %eax @@ -140,20 +134,9 @@ movl %eax, tmp_store movl __current, %eax + # nested intr: restore saved context - popl 8(%eax) # depth - popl 12(%eax) # eax - popl 16(%eax) # ebx - popl 20(%eax) # ecx - popl 24(%eax) # edx - popl 28(%eax) # edi - popl 32(%eax) # ebp - popl 36(%eax) # esi - popl 40(%eax) # ds - popl 44(%eax) # es - popl 48(%eax) # fs - popl 52(%eax) # gs - popl 56(%eax) # esp + popl proc_intr_ctx(%eax) addl $8, %esp @@ -170,8 +153,9 @@ shll $3, %eax addl $12, %eax addl %esp, %eax - movl %eax, (_tss + 4) + movl %eax, (_tss + tss_esp0_off) movl tmp_store, %eax + iret .global switch_to @@ -181,8 +165,8 @@ popl %ebx # next movl __current, %eax - movl 64(%eax), %ecx # __current->pagetable - movl 64(%ebx), %eax # next->pagetable + movl proc_page_table(%eax), %ecx # __current->pagetable + movl proc_page_table(%ebx), %eax # next->pagetable cmpl %ecx, %eax # if(next->pagtable != __current->pagetable) { jz 1f @@ -194,27 +178,37 @@ # 我们已经处在了新的地址空间，为了避免影响其先前的栈布局 # 需要使用一个临时的栈空间 movl $tmp_stack, %esp + call signal_dispatch # kernel/signal.c test %eax, %eax # do we have signal to handle? jz 1f + + # 更新 tss + movl proc_intr_ctx(%ebx), %ecx # __current->intr_ctx + movl %ecx, (tss_esp0_off + _tss) + jmp handle_signal + 1: - leal 8(%ebx), %eax + movl proc_intr_ctx(%ebx), %eax jmp soft_iret .global handle_signal handle_signal: # 注意1：任何对proc_sig的布局改动，都须及时的保证这里的一致性！ # 注意2：handle_signal在调用之前，须确保proc_sig已经写入用户栈！ - leal 8(%eax), %ebx # arg1 in %eax: addr of proc_sig structure in user stack + # arg1 in %eax: addr of proc_sig structure in user stack + movl psig_saved_ictx(%eax), %ebx # %ebx = &proc_sig->saved_ictx - pushl $UDATA_SEG # proc_sig->prev_context.proc_regs.ss + pushl $UDATA_SEG pushl %eax # esp - movl 48(%ebx), %ebx - pushl 68(%ebx) # proc_sig->prev_context.proc_regs.execp->eflags + + movl iexecp(%ebx), %ebx + pushl exeflags(%ebx) # proc_sig->saved_ictx->execp->eflags + pushl $UCODE_SEG # cs - pushl $sig_wrapper # eip for sig wrapper + pushl psig_sigact(%eax) # %eip = proc_sig->sigact movw $UDATA_SEG, %cx # switch data seg to user mode movw %cx, %es @@ -222,21 +216,4 @@ movw %cx, %fs movw %cx, %gs - iret - -.section .usrtext - sig_wrapper: # in user mode - movl %esp, %eax - and $0xfffffff0, %esp - subl $8, %esp - pushl %eax # Addr to proc_sig structure - pushl 4(%eax) # proc_sig->sig_num ---- 16 bytes aligned - - call *(%eax) # invoke signal handler - - # invoke the sigreturn syscall to exit the signal wrapper - movl $__SYSCALL_sigreturn, %eax - movl 4(%esp), %ebx - int $LUNAIX_SYS_CALL - - ud2 # never reach! \ No newline at end of file + iret \ No newline at end of file