start initial irq handling

+ Still lots todo, and I'm not entirely sure how I should handle program
  space switches (mainly since the kernel uses the process' stack, maybe
		  it shouldn't?)

10 files changed, 86 insertions, 8 deletions

diff --git a/arch/riscv64/conf/init b/arch/riscv64/conf/init
index f05254f..c415457 100755
--- a/arch/riscv64/conf/init
+++ b/arch/riscv64/conf/init
diff --git a/arch/riscv64/conf/initrd b/arch/riscv64/conf/initrd
index 90344c1..6d2ac10 100644
--- a/arch/riscv64/conf/initrd
+++ b/arch/riscv64/conf/initrd
diff --git a/arch/riscv64/conf/s.S b/arch/riscv64/conf/s.S
index 80a3a11..1344f69 100644
--- a/arch/riscv64/conf/s.S
+++ b/arch/riscv64/conf/s.S
@@ -1,4 +1,9 @@
 .text
 .global _start
 _start:
+li a0, 1
+li a1, 2
+li a2, 3
+li a3, 4
+li a4, 5
 ecall
diff --git a/arch/riscv64/include/csr.h b/arch/riscv64/include/csr.h
index 7f9fc1f..39e8dc9 100644
--- a/arch/riscv64/include/csr.h
+++ b/arch/riscv64/include/csr.h
@@ -1,8 +1,6 @@
 #ifndef APOS_CSR_H
 #define APOS_CSR_H
 
-#include <apos/utils.h>
-
 #define SATP_MODE_Sv32       0x80000000
 #define SATP_MODE_Sv39       0x8000000000000000
 #define SATP_MODE_Sv48       0x9000000000000000
diff --git a/arch/riscv64/kernel/head.S b/arch/riscv64/kernel/head.S
new file mode 100644
index 0000000..b8ad295
--- /dev/null
+++ b/arch/riscv64/kernel/head.S
@@ -0,0 +1,64 @@
+#include <csr.h>
+
+.section .text
+.global handle_irq
+handle_irq:
+	addi    sp,sp,-144
+	sd      ra,136(sp)
+	sd      t0,128(sp)
+	sd      t1,120(sp)
+	sd      t2,112(sp)
+	sd      s0,104(sp)
+	sd      a0,96(sp)
+	sd      a1,88(sp)
+	sd      a2,80(sp)
+	sd      a3,72(sp)
+	sd      a4,64(sp)
+	sd      a5,56(sp)
+	sd      a6,48(sp)
+	sd      a7,40(sp)
+	sd      t3,32(sp)
+	sd      t4,24(sp)
+	sd      t5,16(sp)
+	sd      t6,8(sp)
+	addi    s0,sp,144
+	/* load supervisor cause */
+	csrr s4, CSR_SCAUSE
+	/* interrupts fall through, exceptions jump */
+	bge s4, zero, handle_exception
+	/* TODO: handle interrupts */
+	j restore_all
+
+handle_exception:
+	li t0, EXC_SYSCALL
+	/* system exceptions fall through, syscalls jump */
+	beq s4, t0, handle_syscall
+	j	restore_all
+
+handle_syscall:
+	jal	syscall_dispatch
+	j	restore_noreturn
+
+restore_all:
+	ld      a0,96(sp)
+
+restore_noreturn:
+	ld      ra,136(sp)
+	ld      t0,128(sp)
+	ld      t1,120(sp)
+	ld      t2,112(sp)
+	ld      s0,104(sp)
+	ld      a1,88(sp)
+	ld      a2,80(sp)
+	ld      a3,72(sp)
+	ld      a4,64(sp)
+	ld      a5,56(sp)
+	ld      a6,48(sp)
+	ld      a7,40(sp)
+	ld      t3,32(sp)
+	ld      t4,24(sp)
+	ld      t5,16(sp)
+	ld      t6,8(sp)
+	addi    sp,sp,144
+	/* assume supervisor for now */
+	sret
diff --git a/arch/riscv64/kernel/irq.c b/arch/riscv64/kernel/irq.c
index 27e0bd0..d350426 100644
--- a/arch/riscv64/kernel/irq.c
+++ b/arch/riscv64/kernel/irq.c
@@ -13,10 +13,8 @@ void init_irq(void *fdt)
 	info("CSR_SIE: %lx\n", s);
 }
 
-__aligned(4) void handle_irq()
+void handle_sys_irq()
 {
-	while (1)
-		;
 }
 
 /* very simple for now */
diff --git a/arch/riscv64/kernel/proc.c b/arch/riscv64/kernel/proc.c
index ef8f24e..66325ec 100644
--- a/arch/riscv64/kernel/proc.c
+++ b/arch/riscv64/kernel/proc.c
@@ -5,7 +5,7 @@
 stat_t jump_to_userspace(struct tcb *t, int argc, char **argv)
 {
 	csr_write(CSR_SEPC, t->entry);
-	__asm__ volatile("mv sp, %0\n" : "=r"(t->proc_stack)::"memory");
+	__asm__ volatile("mv sp, %0\n" ::"r"(t->proc_stack_top) : "memory");
 	__asm__ volatile("sret\n" ::: "memory");
 	/* we should never reach this */
 	return ERR_ADDR;
diff --git a/common/mem_regions.c b/common/mem_regions.c
index e994b0e..bbd9a3b 100644
--- a/common/mem_regions.c
+++ b/common/mem_regions.c
@@ -291,8 +291,11 @@ static vm_t __partition_region(struct mem_region_root *r, struct mem_region *m,
  * fs server */
 vm_t alloc_region(struct mem_region_root *r, size_t size, size_t *actual_size)
 {
-	*actual_size = align_up(size, BASE_PAGE_SIZE);
-	size_t pages = __page(*actual_size);
+	size_t asize = align_up(size, BASE_PAGE_SIZE);
+	if (actual_size)
+		*actual_size = asize;
+
+	size_t pages = __page(asize);
 
 	/* find best fitting, alignment etc. */
 	size_t align = 0;
diff --git a/common/proc.c b/common/proc.c
index e0b8c70..ea3ab5d 100644
--- a/common/proc.c
+++ b/common/proc.c
@@ -46,12 +46,18 @@ stat_t init_proc(void *fdt, struct vm_branch *b)
 	if (!t->proc_stack)
 		return ERR_ADDR;
 
+	t->proc_stack_top = t->proc_stack + __proc_stack_size;
+
 	t->call_stack = setup_call_stack(t, __call_stack_size);
 	if (!t->call_stack)
 		return ERR_ADDR;
+	t->call_stack_top = t->call_stack + __call_stack_size;
 
 	flush_tlb();
 
+	/* set current tcb */
+	use_tcb(t);
+
 	/* TODO: move fdt into process space */
 	return jump_to_userspace(t, 1, 0);
 }
diff --git a/include/apos/tcb.h b/include/apos/tcb.h
index 7ed07c5..821d822 100644
--- a/include/apos/tcb.h
+++ b/include/apos/tcb.h
@@ -16,8 +16,12 @@ struct tcb {
 	id_t tid;
 
 	vm_t callback;
+
 	vm_t proc_stack;
+	vm_t proc_stack_top;
+
 	vm_t call_stack;
+	vm_t call_stack_top;
 
 	/* entry point */
 	vm_t entry;