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🆕 syscall模块，实现了第一个系统调用函数sys_printf

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fslongjin
2022-02-16 14:07:53 +08:00
parent 7238e3c13a
commit d3a5048f66
11 changed files with 219 additions and 8 deletions
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40
kernel/exception/entry.S
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@ -99,6 +99,46 @@ Err_Code:
jmp ret_from_exception
// 系统调用入口
// 保存寄存器
ENTRY(system_call)
// 由于sysenter指令会禁用中断，因此要在这里手动开启中断
sti;
subq $0x38, %rsp
cld;
pushq %rax
movq %es, %rax
pushq %rax
movq %ds, %rax
pushq %rax
pushq %rbp
pushq %rdi
pushq %rsi
pushq %rdx
pushq %rcx
pushq %rbx
pushq %r8
pushq %r9
pushq %r10
pushq %r11
pushq %r12
pushq %r13
pushq %r14
pushq %r15
movq $0x10, %rdx
movq %rdx, %ds
movq %rdx, %es
// 将rsp作为参数传递给system_call_function
movq %rsp, %rdi
callq system_call_function
// 从系统调用中返回
ENTRY(ret_from_system_call)
movq %rax, 0x80(%rsp) // 将当前rax的值先存到栈中rax的位置