some code cleanups

Makefile.example

@@ -44,7 +44,7 @@ INCLUDE = -I$(TOPDIR)/include -I$(TOPDIR)/arch/$(ARCH)/include -I$(TOPDIR)/lwip/
 # Compiler options for final code
 CFLAGS = -g -m32 -march=i586 -Wall -O2 -fstrength-reduce -fomit-frame-pointer -finline-functions -ffreestanding $(INCLUDE) $(STACKPROT)
 # Compiler options for debuging
-#CFLAGS = -g -O -m32 -march=i586 -Wall -DWITH_FRAME_POINTER -ffreestanding $(INCLUDE) $(STACKPROT)
+#CFLAGS = -g -O -m32 -march=i586 -Wall -fomit-frame-pointer -ffreestanding $(INCLUDE) $(STACKPROT)
 ARFLAGS = rsv
 LDFLAGS = -T link$(BIT).ld -z max-page-size=4096 --defsym __BUILD_DATE=$(shell date +'%Y%m%d') --defsym __BUILD_TIME=$(shell date +'%H%M%S')
 STRIP_DEBUG = --strip-debug

Makefile.scc

@@ -44,7 +44,7 @@ INCLUDE = -I$(TOPDIR)/include -I$(TOPDIR)/arch/$(ARCH)/include -I$(TOPDIR)/lwip/
 # Compiler options for final code
 CFLAGS = -g -m32 -march=i586 -Wall -O2 -fstrength-reduce -fomit-frame-pointer -finline-functions -ffreestanding $(INCLUDE) $(STACKPROT)
 # Compiler options for debuging
-#CFLAGS = -g -O -m32 -march=i586 -Wall -DWITH_FRAME_POINTER -ffreestanding $(INCLUDE) $(STACKPROT)
+#CFLAGS = -g -O -m32 -march=i586 -Wall -fomit-frame-pointer -ffreestanding $(INCLUDE) $(STACKPROT)
 ARFLAGS = rsv
 LDFLAGS = -T link$(BIT).ld -z max-page-size=4096 --defsym __BUILD_DATE=$(shell date +'%Y%m%d') --defsym __BUILD_TIME=$(shell date +'%H%M%S')
 STRIP_DEBUG = --strip-debug

arch/x86/include/asm/processor.h

@@ -308,11 +308,6 @@ static inline size_t lsb(size_t i)
 	return ret;
 }
 
-/** @brief Read extended instruction pointer
- * @return The EIP's value
- */
-uint32_t read_eip(void);
-
 /// A one-instruction-do-nothing
 #define NOP1	asm volatile ("nop")
 /// Do nothing for 2 instructions

arch/x86/kernel/entry32.asm

@@ -109,10 +109,12 @@ flush2:
     ret
 
 ; determines the current instruction pointer (after the jmp)
-global read_eip
+global read_ip
-read_eip:
+read_ip:
-    pop eax                     ; Get the return address
+    mov eax, [esp+4]
-    jmp eax                     ; Return. Can't use RET because return
+    pop DWORD [eax]             ; Get the return address
+    add esp, 4                  ; Dirty Hack! read_ip cleanup the stacl
+    jmp [eax]                   ; Return. Can't use RET because return
                                 ; address popped off the stack.
 
 ; In just a few pages in this tutorial, we will add our Interrupt

arch/x86/kernel/gdt.c

@@ -17,6 +17,7 @@
  * This file is part of MetalSVM.
  */
 
+#include <metalsvm/stdio.h>
 #include <metalsvm/string.h>
 #include <metalsvm/stdlib.h>
 #include <metalsvm/tasks.h>
@@ -58,51 +59,53 @@ size_t get_stack(uint32_t id)
 int arch_fork(task_t* task)
 {
 	uint16_t cs = 0x08;
-	uint32_t id, esp;
+	uint32_t id;
 	struct state* state;
 	task_t* curr_task = per_core(current_task);
+	size_t esp, state_size;
 
 	if (BUILTIN_EXPECT(!task, 0))
 		return -EINVAL;
 	id = task->id;
 
+#ifdef CONFIG_X86_32
+	state_size = sizeof(struct state) - 2*sizeof(size_t);
+#else
+	state_size = sizeof(struct state);
+#endif
+
 	// copy kernel stack of the current task
 	mb();
 	memcpy(kstacks[id], kstacks[curr_task->id], KERNEL_STACK_SIZE);
-	mb();
 
 #ifdef CONFIG_X86_32
-	asm volatile ("mov %%esp, %0" : "=r"(esp));
+	asm volatile ("mov %%esp, %0" : "=m"(esp));
-	esp -= (uint32_t) kstacks[curr_task->id];
+	esp -= (size_t) kstacks[curr_task->id];
-	esp += (uint32_t) kstacks[id]; 
+	esp += (size_t) kstacks[id]; 
 
-	state = (struct state*) (esp - sizeof(struct state) + 2*sizeof(size_t));
+	state = (struct state*) (esp - state_size);
-	memset(state, 0x00, sizeof(struct state) - 2*sizeof(size_t));
+	memset(state, 0x00, state_size);
 
-	asm volatile ("pusha; pop %0" : "=r"(state->edi));
+	asm volatile ("pusha; pop %0" : "=m"(state->edi));
-	asm volatile ("pop %0" : "=r"(state->esi));
+	asm volatile ("pop %0" : "=m"(state->esi));
-	asm volatile ("pop %0" : "=r"(state->ebp));
+	asm volatile ("pop %0" : "=m"(state->ebp));
 	asm volatile ("add $4, %%esp" ::: "%esp");
-	asm volatile ("pop %0" : "=r"(state->ebx));
+	asm volatile ("pop %0" : "=m"(state->ebx));
-	asm volatile ("pop %0" : "=r"(state->edx));
+	asm volatile ("pop %0" : "=m"(state->edx));
-	asm volatile ("pop %0" : "=r"(state->ecx));
+	asm volatile ("pop %0" : "=m"(state->ecx));
-	asm volatile ("pop %0" : "=r"(state->eax));
+	asm volatile ("pop %0" : "=m"(state->eax));
 
-#ifdef WITH_FRAME_POINTER
+	state->esp = esp;
-	state->ebp -= (uint32_t) kstacks[curr_task->id];
-	state->ebp += (uint32_t) kstacks[id];
-#endif
-	state->esp = (uint32_t) state;
 	task->stack = (size_t*) state;
 	state->int_no = 0xB16B00B5;
 	state->error =  0xC03DB4B3;
 	state->cs = cs;
 	// store the current EFLAGS
-	asm volatile ("pushf; pop %%eax" : "=a"(state->eflags));
+	asm volatile ("pushf; pop %0" : "=m"(state->eflags));
 	// enable interrupts
 	state->eflags |= (1 << 9);
-	// This will be the entry point for the new task.
+	// This will be the entry point for the new task. read_ip cleanups the stack
-	asm volatile ("call read_eip" : "=a"(state->eip));
+	asm volatile ("push %0; call read_ip" :: "r"(&state->eip) : "%eax");
 #else
 #warning Currently, not supported!
 	return -1;