X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/98fd6cb58b5bbc55cd9ceb45bd27b45a3b222df7..04ee277abd77fc51c5ab02ee58790a859607ea24:/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 e88c32f..80dee1a 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 @@ -9,43 +12,60 @@ .global debug_resv debug_resv: .skip 16 + tmp_store: + .skip 4 #endif .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] - [esp] - eflags > offset = 48 + 16 = 64 - cs - eip - err_code - vector > offset = 28 + 16 + 4 = 48 - esp + msa: [ss] > 76 -> 28 + [esp] > 72 -> 24 + eflags > 68 -> 20 + cs > 64 -> 16 + eip > 60 -> 12 + err_code > 56 -> 8 + vector > offset = 52 -> 4 + [saved_prev_ctx] > offset = 0 + --- + esp > 12 * 4 = 48 gs fs es - ds > offset = 7 * 4 = 28 + ds > offset = 8 * 4 = 32 esi ebp edi edx ecx ebx - lsa: eax > offset = 0 + eax + lsa: depth > offset = 0 las: Least Significant Address msa: Most Significant Address */ cld + + subl $4, %esp pushl %esp subl $16, %esp @@ -62,30 +82,39 @@ pushl %ebx pushl %eax - movl 60(%esp), %eax /* 取出 %cs */ + movl __current, %eax + movl proc_intr_ctx(%eax), %eax + incl %eax + pushl %eax # nested intr: current depth + + 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, %eax - # 保存x87FPU的状态 - movl 64(%eax), %ebx - fxsave (%ebx) + # 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 iuesp(%esp), %ebx # 取出esp + movl %ebx, proc_ustack_top(%eax) # 存入__current->ustack_top - movl 68(%esp), %ebx # 取出esp - movl %ebx, 56(%eax) # 存入__current->ustack_top + # Save x87 context to user stack, rather than kernel's memory. + # XXX: what will happen if we triggered a page fault during fxsave? + movl iuesp(%esp), %eax + andl $stack_alignment, %eax + subl $512, %eax + fxsave (%eax) + /* kernel space same-level switch */ 1: movl %esp, %eax - andl $0xfffffff0, %esp + andl $stack_alignment, %esp subl $16, %esp movl %eax, (%esp) @@ -99,17 +128,26 @@ #ifdef __ASM_INTR_DIAGNOSIS movl %eax, (debug_resv + 8) - movl 44(%esp), %eax - movl 8(%eax), %eax + movl iesp(%esp), %eax + movl exeip(%eax), %eax movl %eax, (debug_resv + 4) # eip #endif - movl (__current), %eax - movl 64(%eax), %eax + // movl __current, %eax + // movl proc_fxstate(%eax), %eax - test %eax, %eax # do we have stored x87 context? + // test %eax, %eax # do we have stored x87 context? + + movl ics(%esp), %eax + andl $3, %eax jz 1f - fxrstor (%eax) + + movl iuesp(%esp), %eax + andl $stack_alignment, %eax + subl $512, %eax + fxrstor (%eax) + 1: + popl %eax # discard isr_param::depth popl %eax popl %ebx popl %ecx @@ -125,24 +163,31 @@ movl 16(%esp), %esp + movl %eax, tmp_store + movl __current, %eax + + + # nested intr: restore saved context + popl proc_intr_ctx(%eax) + addl $8, %esp - pushl %eax #ifdef __ASM_INTR_DIAGNOSIS - movl 4(%esp), %eax + movl (%esp), %eax movl %eax, debug_resv #endif # 处理TSS.ESP的一些边界条件。如果是正常iret（即从内核模式*优雅地*退出） # 那么TSS.ESP0应该为iret进行弹栈后，%esp的值。 # 所以这里的边界条件是：如返回用户模式，iret会额外弹出8个字节（ss,esp） - movl 8(%esp), %eax + movl 4(%esp), %eax andl $3, %eax setnz %al shll $3, %eax - addl $16, %eax + addl $12, %eax addl %esp, %eax - movl %eax, (_tss + 4) - popl %eax + movl %eax, (_tss + tss_esp0_off) + movl tmp_store, %eax + iret .global switch_to @@ -152,8 +197,8 @@ popl %ebx # next movl __current, %eax - movl 60(%eax), %ecx # __current->pagetable - movl 60(%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 @@ -165,26 +210,36 @@ # 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 - pushl 64(%ebx) # proc_sig->prev_context.proc_regs.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 @@ -192,21 +247,4 @@ 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