X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/blobdiff_plain/94a87fe25c5ec021daf16edd64058ed6a37aba7d..191c47396747e54457510c7e126b6ba098fefbbd:/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 62c9ec5..48dff2f 100644
--- a/lunaix-os/kernel/asm/x86/interrupt.S
+++ b/lunaix-os/kernel/asm/x86/interrupt.S
@@ -22,10 +22,17 @@
         .skip 16
 #endif
 
+.section .bss
+    .align 16
+    lo_tmp_stack:
+        .skip 128
+    tmp_stack:
+
 .section .text
     isr_template FAULT_DIVISION_ERROR
     isr_template FAULT_GENERAL_PROTECTION, no_error_code=0
     isr_template FAULT_PAGE_FAULT, no_error_code=0
+    isr_template FAULT_STACK_SEG_FAULT, no_error_code=0
 
     isr_template LUNAIX_SYS_PANIC
     isr_template LUNAIX_SYS_CALL
@@ -104,10 +111,11 @@
 
         call intr_handler
 
+        movl (%esp), %eax
+
     .global soft_iret
     soft_iret:
-        cli
-        popl %esp
+        movl %eax, %esp
 
         popl %eax
         popl %ebx
@@ -126,21 +134,60 @@
 
         addl $8, %esp
 
-#ifdef __ASM_INTR_DIAGNOSIS
         pushl %eax
+#ifdef __ASM_INTR_DIAGNOSIS
         movl 4(%esp), %eax
         movl %eax, debug_resv
-        popl %eax
 #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
+        andl $3, %eax
+        setnz %al
+        shll $3, %eax
+        addl $16, %eax
+        addl %esp, %eax
+        movl %eax, (_tss + 4)
+        popl %eax
         iret
 
+    .global switch_to
+    switch_to:
+        # 约定
+        # arg1: 目标进程PCB地址 (next
+
+        popl %ecx               # next
+        movl __current, %eax    
+        movl 88(%eax), %ebx     # __current->pagetable
+        movl 88(%ecx), %eax     # next->pagetable
+        
+        cmpl %ebx, %eax         # if(next->pagtable != __current->pagetable) {
+        jz 1f
+        movl %eax, %cr3         #   cpu_lcr3(next->pagetable)
+                                # }
+    1:
+        movl %ecx, __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
+        jmp handle_signal
+    1:
+        leal 8(%ecx), %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！
-        popl %eax               # arg1: addr of proc_sig structure in user stack
-        leal 8(%eax), %ebx
+        leal 8(%eax), %ebx      # arg1 in %eax: addr of proc_sig structure in user stack
 
-        pushl 72(%ebx)          # proc_sig->prev_context.ss
+        pushl $UDATA_SEG        # proc_sig->prev_context.ss
         pushl %eax              # esp
         pushl 64(%ebx)          # proc_sig->prev_context.eflags
         pushl $UCODE_SEG        # cs
@@ -154,6 +201,7 @@
 
         iret  
 
+.section .usrtext
     sig_wrapper:                # in user mode
         movl %esp, %eax
         and $0xfffffff0, %esp