#define __ASM__
#include <arch/x86/interrupts.h>
-#include <lunaix/common.h>
+#include <arch/x86/i386_asm.h>
+#include <arch/x86/tss.h>
#include <lunaix/syscall.h>
-#define __ASM_INTR_DIAGNOSIS
+#include <arch/x86/interrupt.S.inc>
-.macro isr_template vector, no_error_code=1
- .global _asm_isr\vector
- .type _asm_isr\vector, @function
- _asm_isr\vector:
- .if \no_error_code
- pushl $0x0
- .endif
- pushl $\vector
- jmp interrupt_wrapper
-.endm
+#define __ASM_INTR_DIAGNOSIS
#ifdef __ASM_INTR_DIAGNOSIS
.section .bss
.global debug_resv
debug_resv:
.skip 16
+ tmp_store:
+ .skip 4
#endif
-.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
+.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.
- isr_template LUNAIX_SYS_PANIC
- isr_template LUNAIX_SYS_CALL
+ Be aware the twists, offsets and hidden dependencies!
- isr_template APIC_ERROR_IV
- isr_template APIC_LINT0_IV
- isr_template APIC_TIMER_IV
- isr_template APIC_SPIV_IV
- isr_template RTC_TIMER_IV
- isr_template PC_KBD_IV
+*/
+.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
- gs
- fs
- es
- ds > offset = 7 * 4 = 28
- esi
- ebp
- edi
- edx
- ecx
- ebx
- lsa: eax > offset = 0
-
- las: Least Significant Address
- msa: Most Significant Address
- */
cld
+
+ subl $4, %esp
pushl %esp
subl $16, %esp
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 68(%esp), %ebx # 取出esp
- movl %ebx, 84(%eax) # 存入__current->ustack_top
+ 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 $0xfffffff0, %esp
+ andl $stack_alignment, %esp
subl $16, %esp
movl %eax, (%esp)
call intr_handler
+ movl (%esp), %eax
+
.global soft_iret
soft_iret:
- cli
- popl %esp
+ 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
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
- pushl %eax
- movl 4(%esp), %eax
+ movl (%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 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！
- popl %eax # arg1: addr of proc_sig structure in user stack
- leal 8(%eax), %ebx
+ # arg1 in %eax: addr of proc_sig structure in user stack
+ movl psig_saved_ictx(%eax), %ebx # %ebx = &proc_sig->saved_ictx
- pushl 72(%ebx) # proc_sig->prev_context.ss
+ pushl $UDATA_SEG
pushl %eax # esp
- pushl 64(%ebx) # proc_sig->prev_context.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
movw %cx, %fs
movw %cx, %gs
- iret
-
- 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
git://scm.lunaixsky.com / lunaix-os.git / blobdiff