| /* |
| * x86 segmentation related helpers (user-mode code): |
| * TSS, interrupts, system calls, jumps and call/task gates, descriptors |
| * |
| * Copyright (c) 2003 Fabrice Bellard |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "qemu/osdep.h" |
| #include "cpu.h" |
| #include "exec/helper-proto.h" |
| #include "exec/exec-all.h" |
| #include "exec/cpu_ldst.h" |
| #include "tcg/helper-tcg.h" |
| #include "tcg/seg_helper.h" |
| |
| void helper_syscall(CPUX86State *env, int next_eip_addend) |
| { |
| CPUState *cs = env_cpu(env); |
| |
| cs->exception_index = EXCP_SYSCALL; |
| env->exception_is_int = 0; |
| env->exception_next_eip = env->eip + next_eip_addend; |
| cpu_loop_exit(cs); |
| } |
| |
| /* |
| * fake user mode interrupt. is_int is TRUE if coming from the int |
| * instruction. next_eip is the env->eip value AFTER the interrupt |
| * instruction. It is only relevant if is_int is TRUE or if intno |
| * is EXCP_SYSCALL. |
| */ |
| static void do_interrupt_user(CPUX86State *env, int intno, int is_int, |
| int error_code, target_ulong next_eip) |
| { |
| if (is_int) { |
| SegmentCache *dt; |
| target_ulong ptr; |
| int dpl, cpl, shift; |
| uint32_t e2; |
| |
| dt = &env->idt; |
| if (env->hflags & HF_LMA_MASK) { |
| shift = 4; |
| } else { |
| shift = 3; |
| } |
| ptr = dt->base + (intno << shift); |
| e2 = cpu_ldl_kernel(env, ptr + 4); |
| |
| dpl = (e2 >> DESC_DPL_SHIFT) & 3; |
| cpl = env->hflags & HF_CPL_MASK; |
| /* check privilege if software int */ |
| if (dpl < cpl) { |
| raise_exception_err(env, EXCP0D_GPF, (intno << shift) + 2); |
| } |
| } |
| |
| /* Since we emulate only user space, we cannot do more than |
| exiting the emulation with the suitable exception and error |
| code. So update EIP for INT 0x80 and EXCP_SYSCALL. */ |
| if (is_int || intno == EXCP_SYSCALL) { |
| env->eip = next_eip; |
| } |
| } |
| |
| void x86_cpu_do_interrupt(CPUState *cs) |
| { |
| X86CPU *cpu = X86_CPU(cs); |
| CPUX86State *env = &cpu->env; |
| |
| /* if user mode only, we simulate a fake exception |
| which will be handled outside the cpu execution |
| loop */ |
| do_interrupt_user(env, cs->exception_index, |
| env->exception_is_int, |
| env->error_code, |
| env->exception_next_eip); |
| /* successfully delivered */ |
| env->old_exception = -1; |
| } |
| |
| void cpu_x86_load_seg(CPUX86State *env, X86Seg seg_reg, int selector) |
| { |
| if (!(env->cr[0] & CR0_PE_MASK) || (env->eflags & VM_MASK)) { |
| int dpl = (env->eflags & VM_MASK) ? 3 : 0; |
| selector &= 0xffff; |
| cpu_x86_load_seg_cache(env, seg_reg, selector, |
| (selector << 4), 0xffff, |
| DESC_P_MASK | DESC_S_MASK | DESC_W_MASK | |
| DESC_A_MASK | (dpl << DESC_DPL_SHIFT)); |
| } else { |
| helper_load_seg(env, seg_reg, selector); |
| } |
| } |