From c53533a539638c1c0ad4f4c99c091ae7972cfd8b Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Sat, 15 Oct 2011 08:24:34 +0800
Subject: [PATCH] Usermode/ld-acess - Syscall stub changes

- SYS_CLONE stack switch moved to usermode
- ARMv7 syscall fixes
---
 .../Libraries/ld-acess.so_src/arch/armv7.S.h  | 46 +++++++++++++++++--
 .../Libraries/ld-acess.so_src/arch/x86.asm.h  | 10 ++++
 .../ld-acess.so_src/arch/x86_64.asm.h         | 12 +++++
 3 files changed, 65 insertions(+), 3 deletions(-)

diff --git a/Usermode/Libraries/ld-acess.so_src/arch/armv7.S.h b/Usermode/Libraries/ld-acess.so_src/arch/armv7.S.h
index 75c56d8f..85a3ac69 100644
--- a/Usermode/Libraries/ld-acess.so_src/arch/armv7.S.h
+++ b/Usermode/Libraries/ld-acess.so_src/arch/armv7.S.h
@@ -7,7 +7,7 @@
 .globl _start
 .extern SoMain
 _start:
-	push {r1,r2,r3}
+	pop {r0}
 	bl SoMain
 	
 	mov r4, r0
@@ -58,19 +58,59 @@ _errno:	.long	0	@ Placed in .text, to allow use of relative addressing
 	mov pc, lr
 .endm
 
+.macro syscall5 _name, _num
+.globl \_name
+\_name:
+	push {r4}
+	ldr r4, [sp,#4]
+	svc #\_num
+	str r2, _errno
+	pop {r4}
+	mov pc, lr
+.endm
+
+.macro syscall6 _name, _num
+.globl \_name
+\_name:
+	push {r4,r5}
+	ldr r4, [sp,#8]
+	ldr r5, [sp,#12]
+	svc #\_num
+	str r2, _errno
+	pop {r4,r5}
+	mov pc, lr
+.endm
+
 #define SYSCALL0(_name,_num)	syscall0 _name, _num
 #define SYSCALL1(_name,_num)	SYSCALL0(_name, _num)
 #define SYSCALL2(_name,_num)	SYSCALL0(_name, _num)
 #define SYSCALL3(_name,_num)	SYSCALL0(_name, _num)
 #define SYSCALL4(_name,_num)	SYSCALL0(_name, _num)
 // TODO: 5/6 need special handling, because the args are on the stack
-#define SYSCALL5(_name,_num)	SYSCALL0(_name, _num)
-#define SYSCALL6(_name,_num)	SYSCALL0(_name, _num)
+#define SYSCALL5(_name,_num)	syscall5 _name, _num
+#define SYSCALL6(_name,_num)	syscall6 _name, _num
 
 // Override the clone syscall
 #define _exit	_exit_raw
+#define _clone	_clone_raw
 #include "syscalls.s.h"
 #undef _exit
+#undef _clone
+
+.globl _clone
+_clone:
+	push {r4}
+	mov r4, r1
+	svc #SYS_CLONE
+	str r2, _errno
+	tst r4, r4
+	beq _clone_ret
+	@ If in child, set SP
+	tst r0,r0
+	movne sp, r4
+_clone_ret:
+	pop {r4}
+	mov pc, lr
 
 .globl _exit
 _exit:
diff --git a/Usermode/Libraries/ld-acess.so_src/arch/x86.asm.h b/Usermode/Libraries/ld-acess.so_src/arch/x86.asm.h
index a569637d..4de25277 100644
--- a/Usermode/Libraries/ld-acess.so_src/arch/x86.asm.h
+++ b/Usermode/Libraries/ld-acess.so_src/arch/x86.asm.h
@@ -161,6 +161,7 @@ clone:
 	push ebp
 	mov ebp, esp
 	push ebx
+	push edx
 	
 	mov ebx, [ebp+12]	; Get new stack pointer
 	
@@ -192,11 +193,20 @@ clone:
 	sub ebx, 12
 	%endif
 .doCall:
+	mov edx, ebx	; Save new stack
 	mov eax, SYS_CLONE
 	mov ecx, ebx	; Stack
 	mov ebx, [ebp+8]	; Flags
 	SYSCALL_OP
 	mov [_errno], ebx
+	
+	test eax, eax
+	jnz .ret
+	test edx, edx
+	jz .ret
+	mov esp, edx
+.ret:
+	pop edx
 	pop ebx
 	pop ebp
 	ret
diff --git a/Usermode/Libraries/ld-acess.so_src/arch/x86_64.asm.h b/Usermode/Libraries/ld-acess.so_src/arch/x86_64.asm.h
index ea605ef6..62fc400a 100644
--- a/Usermode/Libraries/ld-acess.so_src/arch/x86_64.asm.h
+++ b/Usermode/Libraries/ld-acess.so_src/arch/x86_64.asm.h
@@ -152,6 +152,9 @@ clone:
 	push rbp
 	mov rbp, rsp
 	push rbx
+	push r11
+	
+	mov r12, rsi	; Save in a reg for after the clone
 	
 	; Check if the new stack is being used
 	test rsi, rsi
@@ -166,10 +169,19 @@ clone:
 	mov eax, SYS_CLONE
 	SYSCALL_OP
 	mov [rel _errno], ebx
+
+	; Change stack pointer
+	test eax, eax
+	jnz .ret
+	test r12, r12
+	jz .ret
+	mov rsp, rsi
+.ret:
 	pop rbx
 	pop rbp
 	ret
 
+
 [global _exit:func]
 _exit:
 	xor eax, eax
-- 
2.20.1