From 19b68b7e9f59c00df6d2d894ab0a287bc195304b Mon Sep 17 00:00:00 2001
From: Baptiste Wicht <baptiste.wicht@gmail.com>
Date: Sat, 18 Jan 2014 17:59:05 +0100
Subject: [PATCH] Improve system call systems

---
 kernel/include/interrupts.hpp |  6 ++++
 kernel/src/interrupts.cpp     |  6 ++--
 kernel/src/syscalls.s         | 68 +++++++++++++++--------------------
 kernel/src/system_calls.cpp   |  2 +-
 4 files changed, 38 insertions(+), 44 deletions(-)

diff --git a/kernel/include/interrupts.hpp b/kernel/include/interrupts.hpp
index 0d61a86b..e8b609bc 100644
--- a/kernel/include/interrupts.hpp
+++ b/kernel/include/interrupts.hpp
@@ -32,6 +32,12 @@ struct syscall_regs {
     uint64_t rdx;
     uint64_t rsi;
     uint64_t rdi;
+    uint64_t r8;
+    uint64_t r9;
+    uint64_t r10;
+    uint64_t r11;
+    uint64_t r12;
+    uint64_t code;
 } __attribute__((packed));
 
 void setup_interrupts();
diff --git a/kernel/src/interrupts.cpp b/kernel/src/interrupts.cpp
index dfac9a8d..697bdfc6 100644
--- a/kernel/src/interrupts.cpp
+++ b/kernel/src/interrupts.cpp
@@ -241,11 +241,9 @@ void _irq_handler(size_t code){
 }
 
 void _syscall_handler(interrupt::syscall_regs regs){
-    auto code = regs.rdi;
-
     //If there is a handler call, it
-    if(syscall_handlers[code]){
-        syscall_handlers[code](regs);
+    if(syscall_handlers[regs.code]){
+        syscall_handlers[regs.code](regs);
     }
 
     //TODO Emit an error somehow if there is no handler
diff --git a/kernel/src/syscalls.s b/kernel/src/syscalls.s
index 731f1fbe..cb6373c2 100644
--- a/kernel/src/syscalls.s
+++ b/kernel/src/syscalls.s
@@ -24,80 +24,70 @@
 _syscall0:
     cli
 
-    push rdi
-    mov rdi, 0
+    push 0
 
     jmp syscall_common_handler
 
 _syscall1:
     cli
 
-    push rdi
-    mov rdi, 1
+    push 1
 
     jmp syscall_common_handler
 
 _syscall2:
     cli
 
-    push rdi
-    mov rdi, 2
+    push 2
 
     jmp syscall_common_handler
 
 _syscall3:
     cli
 
-    push rdi
-    mov rdi, 3
+    push 3
 
     jmp syscall_common_handler
 
 _syscall4:
     cli
 
-    push rdi
-    mov rdi, 4
+    push 4
 
     jmp syscall_common_handler
 
 _syscall5:
     cli
 
-    push rdi
-    mov rdi, 5
+    push 5
 
     jmp syscall_common_handler
 
 _syscall6:
     cli
 
-    push rdi
-    mov rdi, 6
+    push 6
 
     jmp syscall_common_handler
 
 _syscall7:
     cli
 
-    push rdi
-    mov rdi, 7
+    push 7
 
     jmp syscall_common_handler
 
 _syscall8:
     cli
 
-    push rdi
-    mov rdi, 8
+    push 8
 
     jmp syscall_common_handler
 
 _syscall9:
     cli
 
-    push rdi
-    mov rdi, 9
+    push 9
 
     jmp syscall_common_handler
 
@@ -105,33 +95,33 @@ _syscall9:
 
 //TODO Check if really safe to trash r12
 syscall_common_handler:
-    push r8
-    push r9
-    push r10
-    push r11
     push r12
-    push rax
-    push rbx
-    push rcx
-    push rdx
-    push rsi
+    push r11
+    push r10
+    push r9
+    push r8
     push rdi
+    push rsi
+    push rdx
+    push rcx
+    push rbx
+    push rax
 
     call _syscall_handler
 
-    pop rdi
-    pop rsi
-    pop rdx
-    pop rcx
-    pop rbx
     pop rax
-    pop r12
-    pop r11
-    pop r10
-    pop r9
+    pop rbx
+    pop rcx
+    pop rdx
+    pop rsi
+    pop rdi
     pop r8
+    pop r9
+    pop r10
+    pop r11
+    pop r12
 
     //Was pushed by the base handler code
-    pop rdi
+    add rsp, 8
 
     iretq // iret will clean the other automatically pushed stuff
diff --git a/kernel/src/system_calls.cpp b/kernel/src/system_calls.cpp
index 2017a4ba..5807ffdd 100644
--- a/kernel/src/system_calls.cpp
+++ b/kernel/src/system_calls.cpp
@@ -13,5 +13,5 @@ void system_call_entry(const interrupt::syscall_regs& regs){
 }
 
 void install_system_calls(){
-    interrupt::register_syscall_handler(interrupt::SYSCALL_FIRST, &system_call_entry);
+    interrupt::register_syscall_handler(0, &system_call_entry);
 }