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b285a1944e
The SysV ABI says that the DF flag should be clear on function entry. That means we have to clear it when jumping into the kernel from some random userspace context.
103 lines
2.8 KiB
C++
103 lines
2.8 KiB
C++
#include <Kernel/Arch/i386/CPU.h>
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#include <Kernel/Process.h>
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#include <Kernel/ProcessTracer.h>
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#include <Kernel/Syscall.h>
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extern "C" void syscall_trap_entry(RegisterDump);
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extern "C" void syscall_trap_handler();
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asm(
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".globl syscall_trap_handler \n"
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"syscall_trap_handler:\n"
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" pushl $0x0\n"
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" pusha\n"
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" pushw %ds\n"
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" pushw %es\n"
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" pushw %fs\n"
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" pushw %gs\n"
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" pushw %ss\n"
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" pushw %ss\n"
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" pushw %ss\n"
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" pushw %ss\n"
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" pushw %ss\n"
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" popw %ds\n"
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" popw %es\n"
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" popw %fs\n"
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" popw %gs\n"
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" cld\n"
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" call syscall_trap_entry\n"
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" popw %gs\n"
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" popw %gs\n"
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" popw %fs\n"
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" popw %es\n"
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" popw %ds\n"
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" popa\n"
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" add $0x4, %esp\n"
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" iret\n");
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namespace Syscall {
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static int handle(RegisterDump&, u32 function, u32 arg1, u32 arg2, u32 arg3);
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void initialize()
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{
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register_user_callable_interrupt_handler(0x82, syscall_trap_handler);
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kprintf("Syscall: int 0x82 handler installed\n");
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}
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#pragma GCC diagnostic ignored "-Wcast-function-type"
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typedef int (Process::*Handler)(u32, u32, u32);
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#define __ENUMERATE_SYSCALL(x) reinterpret_cast<Handler>(&Process::sys$##x),
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static Handler s_syscall_table[] = {
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ENUMERATE_SYSCALLS
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};
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#undef __ENUMERATE_SYSCALL
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int handle(RegisterDump& regs, u32 function, u32 arg1, u32 arg2, u32 arg3)
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{
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ASSERT_INTERRUPTS_ENABLED();
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auto& process = current->process();
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process.did_syscall();
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if (function == SC_exit || function == SC_exit_thread) {
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// These syscalls need special handling since they never return to the caller.
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cli();
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if (auto* tracer = process.tracer())
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tracer->did_syscall(function, arg1, arg2, arg3, 0);
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if (function == SC_exit)
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process.sys$exit((int)arg1);
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else
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process.sys$exit_thread((int)arg1);
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ASSERT_NOT_REACHED();
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return 0;
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}
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if (function == SC_fork)
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return process.sys$fork(regs);
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if (function == SC_sigreturn)
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return process.sys$sigreturn(regs);
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if (function >= Function::__Count) {
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dbg() << process << ": Unknown syscall %u requested (" << arg1 << ", " << arg2 << ", " << arg3 << ")";
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return -ENOSYS;
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}
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return (process.*(s_syscall_table[function]))(arg1, arg2, arg3);
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}
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}
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void syscall_trap_entry(RegisterDump regs)
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{
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auto& process = current->process();
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process.big_lock().lock();
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u32 function = regs.eax;
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u32 arg1 = regs.edx;
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u32 arg2 = regs.ecx;
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u32 arg3 = regs.ebx;
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regs.eax = (u32)Syscall::handle(regs, function, arg1, arg2, arg3);
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if (auto* tracer = process.tracer())
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tracer->did_syscall(function, arg1, arg2, arg3, regs.eax);
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process.big_lock().unlock();
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}
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