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72 lines
2.4 KiB
C
72 lines
2.4 KiB
C
#include "syscall.h"
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#include "../process/process.h"
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// 导出系统调用入口函数，定义在entry.S中
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extern void system_call(void);
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/**
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* @brief 系统调用函数，从entry.S中跳转到这里
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*
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* @param regs 3特权级下的寄存器值,rax存储系统调用号
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* @return ul 对应的系统调用函数的地址
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*/
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ul system_call_function(struct pt_regs *regs)
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{
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return system_call_table[regs->rax](regs);
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}
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/**
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* @brief 初始化系统调用模块
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*
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*/
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void syscall_init()
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{
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// 向MSR寄存器组中的 IA32_SYSENTER_CS寄存器写入内核的代码段的地址
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wrmsr(0x174, KERNEL_CS);
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// 向MSR寄存器组中的 IA32_SYSENTER_ESP寄存器写入内核进程的rbp（在syscall入口中会将rsp减去相应的数值）
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wrmsr(0x175, current_pcb->thread->rbp);
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// 向MSR寄存器组中的 IA32_SYSENTER_EIP寄存器写入系统调用入口的地址。
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wrmsr(0x176, (ul)system_call);
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}
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long enter_syscall(ul syscall_id, ul arg0, ul arg1, ul arg2, ul arg3, ul arg4, ul arg5, ul arg6, ul arg7)
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{
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long err_code;
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__asm__ __volatile__("leaq sysexit_return_address(%%rip), %%rdx \n\t"
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"movq %%rsp, %%rcx \n\t"
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"movq %2, %%r8 \n\t"
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"movq %3, %%r9 \n\t"
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"movq %4, %%r10 \n\t"
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"movq %5, %%r11 \n\t"
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"movq %6, %%r12 \n\t"
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"movq %7, %%r13 \n\t"
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"movq %8, %%r14 \n\t"
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"movq %9, %%r15 \n\t"
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"sysenter \n\t"
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"sysexit_return_address: \n\t"
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: "=a"(err_code)
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: "0"(syscall_id), "m"(arg0), "m"(arg1), "m"(arg2), "m"(arg3), "m"(arg4), "m"(arg5), "m"(arg6), "m"(arg7)
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: "memory", "r8", "r9", "r10", "r11", "r12", "r13", "r14", "r15", "rcx", "rdx");
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return err_code;
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}
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/**
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* @brief 打印字符串的系统调用
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*
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* 当arg1和arg2均为0时，打印黑底白字，否则按照指定的前景色和背景色来打印
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*
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* @param regs 寄存器
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* @param arg0 要打印的字符串
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* @param arg1 前景色
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* @param arg2 背景色
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* @return ul 返回值
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*/
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ul sys_printf(struct pt_regs *regs)
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{
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if(regs->r9 == 0 &®s->r10 == 0)
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printk((char*)regs->r8);
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else printk_color(regs->r9, regs->r10, (char*)regs->r8);
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return 0;
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} |