1 files changed, 109 insertions, 0 deletions
diff --git a/target/i386/tcg/user/seg_helper.c b/target/i386/tcg/user/seg_helper.c
new file mode 100644
index 0000000000..67481b0aa8
--- /dev/null
+++ b/target/i386/tcg/user/seg_helper.c
@@ -0,0 +1,109 @@
+/*
+ *  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"
+
+#ifdef TARGET_X86_64
+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);
+}
+#endif /* TARGET_X86_64 */
+
+/*
+ * 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);
+    }
+}