-#define __ASM__
-#include <arch/i386/interrupts.h>
-#include <arch/i386/i386_asm.h>
-#include <arch/i386/tss.h>
-#include <lunaix/syscall.h>
-#include <arch/i386/interrupt.S.inc>
-
-#define __ASM_INTR_DIAGNOSIS
-
-#ifdef __ASM_INTR_DIAGNOSIS
-.section .bss
- .global debug_resv
- debug_resv:
- .skip 16
- tmp_store:
- .skip 4
-#endif
-
-.section .bss
- .align 16
- lo_tmp_stack:
- .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:
- cld
-
- subl $4, %esp
- pushl %esp
-
- subl $16, %esp
- movw %gs, 12(%esp)
- movw %fs, 8(%esp)
- movw %es, 4(%esp)
- movw %ds, (%esp)
-
- pushl %esi
- pushl %ebp
- pushl %edi
- pushl %edx
- pushl %ecx
- pushl %ebx
- pushl %eax
-
- 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
-
- /* crossing the user/kernel boundary */
- movw $KDATA_SEG, %ax
- movw %ax, %gs
- movw %ax, %fs
- movw %ax, %ds
- movw %ax, %es
-
- movl __current, %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)
-
- # 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 $stack_alignment, %esp
- subl $16, %esp
- movl %eax, (%esp)
-
- call intr_handler
-
- movl (%esp), %eax
-
- .global soft_iret
- soft_iret:
- movl %eax, %esp
-
-#ifdef __ASM_INTR_DIAGNOSIS
- movl %eax, (debug_resv + 8)
- movl iesp(%esp), %eax
- movl exeip(%eax), %eax
- movl %eax, (debug_resv + 4) # eip
-#endif
-
- movl ics(%esp), %eax
- andl $3, %eax
- jz 1f
-
- 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
- popl %ebx
- popl %ecx
- popl %edx
- popl %edi
- popl %ebp
- popl %esi
-
- movw (%esp), %ds
- movw 4(%esp), %es
- movw 8(%esp), %fs
- movw 12(%esp), %gs
-
- movl 16(%esp), %esp
-
- movl %eax, tmp_store
- movl __current, %eax
-
- # nested intr: restore saved context
- popl proc_intr_ctx(%eax)
-
- addl $8, %esp
-
-#ifdef __ASM_INTR_DIAGNOSIS
- 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 4(%esp), %eax
- andl $3, %eax
- setnz %al
- shll $3, %eax
- addl $12, %eax
- addl %esp, %eax
- movl %eax, (_tss + tss_esp0_off)
- movl tmp_store, %eax
-
- iret
-
- .global switch_to
- switch_to:
- # 约定
- # arg1: 目标进程PCB地址 (next
-
- popl %ebx # next
- movl __current, %eax
- 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
- movl %eax, %cr3 # cpu_lcr3(next->pagetable)
- # }
- 1:
- movl %ebx, __current # __current = next
-
- # 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:
- 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！
- # 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
- pushl %eax # esp
-
- movl iexecp(%ebx), %ebx
- pushl exeflags(%ebx) # proc_sig->saved_ictx->execp->eflags
-
- pushl $UCODE_SEG # cs
- pushl psig_sigact(%eax) # %eip = proc_sig->sigact
-
- movw $UDATA_SEG, %cx # switch data seg to user mode
- movw %cx, %es
- movw %cx, %ds
- movw %cx, %fs
- movw %cx, %gs
-
- iret
\ No newline at end of file
git://scm.lunaixsky.com / lunaix-os.git / blobdiff