138 lines
3.4 KiB
C
138 lines
3.4 KiB
C
/**
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* @file kernel/arch/x86_64/user.c
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* @brief Various assembly snippets for jumping to usermode and back.
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*/
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#include <stdint.h>
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#include <kernel/process.h>
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#include <kernel/string.h>
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#include <kernel/arch/x86_64/regs.h>
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#include <kernel/arch/x86_64/mmu.h>
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#include <kernel/arch/x86_64/ports.h>
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void arch_enter_user(uintptr_t entrypoint, int argc, char * argv[], char * envp[], uintptr_t stack) {
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struct regs ret;
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ret.cs = 0x18 | 0x03;
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ret.ss = 0x20 | 0x03;
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ret.rip = entrypoint;
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ret.rflags = (1 << 21) | (1 << 9);
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ret.rsp = stack;
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asm volatile (
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"pushq %0\n"
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"pushq %1\n"
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"pushq %2\n"
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"pushq %3\n"
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"pushq %4\n"
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"swapgs\n"
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"iretq"
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: : "m"(ret.ss), "m"(ret.rsp), "m"(ret.rflags), "m"(ret.cs), "m"(ret.rip),
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"D"(argc), "S"(argv), "d"(envp));
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}
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void arch_enter_signal_handler(uintptr_t entrypoint, int signum) {
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struct regs ret;
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ret.cs = 0x18 | 0x03;
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ret.ss = 0x20 | 0x03;
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ret.rip = entrypoint;
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ret.rflags = (1 << 21) | (1 << 9);
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ret.rsp = (this_core->current_process->syscall_registers->rsp - 128 - 8) & 0xFFFFFFFFFFFFFFF0; /* ensure considerable alignment */
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*(uintptr_t*)ret.rsp = 0x00000008DEADBEEF; /* arbitrarily chosen stack return sentinel IP */
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asm volatile(
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"pushq %0\n"
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"pushq %1\n"
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"pushq %2\n"
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"pushq %3\n"
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"pushq %4\n"
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"swapgs\n"
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"iretq"
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: : "m"(ret.ss), "m"(ret.rsp), "m"(ret.rflags), "m"(ret.cs), "m"(ret.rip),
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"D"(signum));
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__builtin_unreachable();
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}
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__attribute__((naked))
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void arch_resume_user(void) {
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asm volatile (
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"pop %r15\n"
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"pop %r14\n"
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"pop %r13\n"
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"pop %r12\n"
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"pop %r11\n"
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"pop %r10\n"
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"pop %r9\n"
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"pop %r8\n"
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"pop %rbp\n"
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"pop %rdi\n"
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"pop %rsi\n"
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"pop %rdx\n"
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"pop %rcx\n"
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"pop %rbx\n"
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"pop %rax\n"
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"add $16, %rsp\n"
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"swapgs\n"
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"iretq\n"
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);
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__builtin_unreachable();
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}
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static uint8_t saves[512] __attribute__((aligned(16)));
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void arch_restore_floating(process_t * proc) {
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memcpy(&saves,(uint8_t *)&proc->thread.fp_regs,512);
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asm volatile ("fxrstor (%0)" :: "r"(saves));
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}
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void arch_save_floating(process_t * proc) {
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asm volatile ("fxsave (%0)" :: "r"(saves));
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memcpy((uint8_t *)&proc->thread.fp_regs,&saves,512);
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}
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void arch_pause(void) {
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asm volatile (
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"sti\n"
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"hlt\n"
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"cli\n"
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);
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}
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extern void lapic_send_ipi(int i, uint32_t val);
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void arch_fatal(void) {
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for (int i = 0; i < processor_count; ++i) {
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if (i == this_core->cpu_id) continue;
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lapic_send_ipi(processor_local_data[i].lapic_id, 0x447D);
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}
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while (1) {
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asm volatile (
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"cli\n"
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"hlt\n"
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);
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}
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}
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long arch_reboot(void) {
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/* load a null page as an IDT */
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uintptr_t frame = mmu_allocate_a_frame();
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uintptr_t * idt = mmu_map_from_physical(frame << 12);
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memset(idt, 0, 0x1000);
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asm volatile (
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"lidt (%0)"
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: : "r"(idt)
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);
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uint8_t out = 0x02;
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while ((out & 0x02) != 0) {
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out = inportb(0x64);
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}
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outportb(0x64, 0xFE); /* Reset */
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return 0;
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}
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void arch_syscall_return(struct regs * r, long retval) { r->rax = retval; }
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long arch_syscall_number(struct regs * r) { return (unsigned long)r->rax; }
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long arch_syscall_arg0(struct regs * r) { return r->rbx; }
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long arch_syscall_arg1(struct regs * r) { return r->rcx; }
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long arch_syscall_arg2(struct regs * r) { return r->rdx; }
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long arch_syscall_arg3(struct regs * r) { return r->rsi; }
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long arch_syscall_arg4(struct regs * r) { return r->rdi; }
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long arch_stack_pointer(struct regs * r) { return r->rsp; }
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long arch_user_ip(struct regs * r) { return r->rip; }
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