Kernel/Architecture/amd64/SystemCalls.cpp
2022-11-15 15:09:52 +02:00

86 lines
2.2 KiB
C++

#include <syscalls.hpp>
#include <cpu.hpp>
#include "cpu/gdt.hpp"
// https://supercip971.github.io/02-wingos-syscalls.html
using namespace CPU::x64;
// "Core/SystemCalls.cpp"
extern "C" uint64_t SystemCallsHandler(SyscallsFrame *regs);
extern "C" void SystemCallHandlerStub();
extern "C" __attribute__((naked, used, no_stack_protector)) void SystemCallHandlerStub_broken()
{
// asmv(
// // "cmp $0x08, 0x8(%rsp)\n"
// // "je 1f\n"
// "swapgs\n"
// // "1:\n"
// "mov %rsp, 0x8(%gs)\n" // CPUData->TempStack
// "mov 0x0(%gs), %rsp\n" // CPUData->SystemCallStack
// "push $0x1b\n" // user data segment
// "push 0x8(%gs)\n" // saved stack
// "push %r11\n" // saved rflags
// "push $0x23\n" // user code segment
// "push %rcx\n" // Current RIP
// "push %rax\n"
// "push %rbx\n"
// "push %rcx\n"
// "push %rdx\n"
// "push %rsi\n"
// "push %rdi\n"
// "push %rbp\n"
// "push %r8\n"
// "push %r9\n"
// "push %r10\n"
// "push %r11\n"
// "push %r12\n"
// "push %r13\n"
// "push %r14\n"
// "push %r15\n"
// "mov %rsp, %rdi\n"
// "mov $0, %rbp\n"
// "call SystemCallsHandler\n"
// "pop %r15\n"
// "pop %r14\n"
// "pop %r13\n"
// "pop %r12\n"
// "pop %r11\n"
// "pop %r10\n"
// "pop %r9\n"
// "pop %r8\n"
// "pop %rbp\n"
// "pop %rdi\n"
// "pop %rsi\n"
// "pop %rdx\n"
// "pop %rcx\n"
// "pop %rbx\n"
// /* "pop %rax\n" */
// "mov 0x8(%gs), %rsp\n" // CPUData->TempStack
// // "cmp $0x08, 0x8(%rsp)\n"
// // "je 1f\n"
// "swapgs\n"
// // "1:\n"
// "sti\n"
// "sysretq\n");
}
void InitializeSystemCalls()
{
wrmsr(MSR_EFER, rdmsr(MSR_EFER) | 1);
wrmsr(MSR_STAR, ((uint64_t)(GDT_KERNEL_CODE) << 32) | ((uint64_t)(GDT_KERNEL_DATA | 3) << 48));
wrmsr(MSR_LSTAR, (uint64_t)SystemCallHandlerStub);
wrmsr(MSR_SYSCALL_MASK, (uint64_t)(1 << 9));
}