From a255a2ee64106a2ab4f69c7867daef91feb2a241 Mon Sep 17 00:00:00 2001
From: Gabe Black <gabeblack@google.com>
Date: Mon, 25 Nov 2019 23:01:59 -0800
Subject: [PATCH] sim: Add a transitional syscall ABI which defers to Process.

This change adds a transitional ABI which just falls back to the
existing Process syscall arg getters. It should be phased out once each
ISA implements its own actual ABI.

Jira Issue: https://gem5.atlassian.net/browse/GEM5-187

Change-Id: Ic40bd924989f91de70bbce59fda888b79bbbfca4
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/23190
Reviewed-by: Gabe Black <gabeblack@google.com>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
---
 src/sim/syscall_desc.hh | 50 +++++++++++++++++++++++++++++++++++++++--
 1 file changed, 48 insertions(+), 2 deletions(-)

diff --git a/src/sim/syscall_desc.hh b/src/sim/syscall_desc.hh
index e5adf8bd5..c34dc9045 100644
--- a/src/sim/syscall_desc.hh
+++ b/src/sim/syscall_desc.hh
@@ -50,12 +50,12 @@
 #include <string>
 
 #include "base/types.hh"
+#include "cpu/thread_context.hh"
 #include "sim/guest_abi.hh"
+#include "sim/process.hh"
 #include "sim/syscall_return.hh"
 
-class Process;
 class SyscallDesc;
-class ThreadContext;
 
 SyscallReturn unimplementedFunc(SyscallDesc *desc, int num,
                                 ThreadContext *tc);
@@ -154,4 +154,50 @@ class SyscallDescABI : public SyscallDesc
     using SyscallDesc::SyscallDesc;
 };
 
+struct DefaultSyscallABI
+{
+    using Position = int;
+};
+
+namespace GuestABI
+{
+
+template <>
+struct Result<DefaultSyscallABI, SyscallReturn>
+{
+    static void
+    store(ThreadContext *tc, const SyscallReturn &ret)
+    {
+        auto *process = tc->getProcessPtr();
+        process->setSyscallReturn(tc, ret);
+    }
+};
+
+template <typename Arg>
+struct Argument<DefaultSyscallABI, Arg,
+    typename std::enable_if<std::is_integral<Arg>::value>::type>
+{
+    static Arg
+    get(ThreadContext *tc, DefaultSyscallABI::Position &position)
+    {
+        auto *process = tc->getProcessPtr();
+        return process->getSyscallArg(tc, position);
+    }
+};
+
+template <typename Arg>
+struct Argument<DefaultSyscallABI, Arg,
+    typename std::enable_if<std::is_pointer<Arg>::value>::type>
+{
+    static Arg
+    get(ThreadContext *tc, DefaultSyscallABI::Position &position)
+    {
+        auto *process = tc->getProcessPtr();
+        RegVal reg = process->getSyscallArg(tc, position);
+        return (Arg)(uintptr_t)(reg);
+    }
+};
+
+} // namespace GuestABI
+
 #endif // __SIM_SYSCALL_DESC_HH__
-- 
2.30.2