Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 67 insertions, 0 deletions

diff --git a/linux-user/host/mips/host-signal.h b/linux-user/host/mips/host-signal.h
new file mode 100644
index 000000000..c666ed8c3
--- /dev/null
+++ b/linux-user/host/mips/host-signal.h
@@ -0,0 +1,67 @@
+/*
+ * host-signal.h: signal info dependent on the host architecture
+ *
+ * Copyright (c) 2003-2005 Fabrice Bellard
+ * Copyright (c) 2021 Linaro Limited
+ *
+ * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#ifndef MIPS_HOST_SIGNAL_H
+#define MIPS_HOST_SIGNAL_H
+
+static inline uintptr_t host_signal_pc(ucontext_t *uc)
+{
+    return uc->uc_mcontext.pc;
+}
+
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.pc = pc;
+}
+
+#if defined(__misp16) || defined(__mips_micromips)
+#error "Unsupported encoding"
+#endif
+
+static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+{
+    uint32_t insn = *(uint32_t *)host_signal_pc(uc);
+
+    /* Detect all store instructions at program counter. */
+    switch ((insn >> 26) & 077) {
+    case 050: /* SB */
+    case 051: /* SH */
+    case 052: /* SWL */
+    case 053: /* SW */
+    case 054: /* SDL */
+    case 055: /* SDR */
+    case 056: /* SWR */
+    case 070: /* SC */
+    case 071: /* SWC1 */
+    case 074: /* SCD */
+    case 075: /* SDC1 */
+    case 077: /* SD */
+#if !defined(__mips_isa_rev) || __mips_isa_rev < 6
+    case 072: /* SWC2 */
+    case 076: /* SDC2 */
+#endif
+        return true;
+    case 023: /* COP1X */
+        /*
+         * Required in all versions of MIPS64 since
+         * MIPS64r1 and subsequent versions of MIPS32r2.
+         */
+        switch (insn & 077) {
+        case 010: /* SWXC1 */
+        case 011: /* SDXC1 */
+        case 015: /* SUXC1 */
+            return true;
+        }
+        break;
+    }
+    return false;
+}
+
+#endif