Fixed trap handler, load kernel stack from trap, fixed init, map a larger swath of memory for init.

risc_v/ch8/src/asm/trap.S

@@ -24,7 +24,6 @@
 	fld	f\i, ((NUM_GP_REGS+(\i))*REG_SIZE)(\basereg)
 .endm
 
-
 .section .text
 .global m_trap_vector
 # This must be aligned by 4 since the last two bits
@@ -69,8 +68,8 @@ m_trap_vector:
 	csrr	a2, mcause
 	csrr	a3, mhartid
 	csrr	a4, mstatus
-	mv		a5, t5
-	ld		sp, 520(a5)
+	la		t0, KERNEL_STACK_END
+	ld		sp, 0(t0)
 	call	m_trap
 
 	# When we get here, we've returned from m_trap, restore registers
@@ -109,6 +108,8 @@ switch_to_user:
 	csrw	mstatus, t0
 	csrw	mepc, a1
 	csrw	satp, a2
+	li		t1, 0xaaa
+	csrw	mie, t1
 	# This fence forces the MMU to flush the TLB. However, since
 	# we're using the PID as the address space identifier, we might
 	# only need this when we create a process. Right now, this ensures

risc_v/ch8/src/lib.rs

@@ -140,6 +140,12 @@ extern "C" fn kinit() -> usize {
 	println!("Getting ready for first process.");
 	println!("Issuing the first context-switch timer.");
 	unsafe {
+		cpu::mscratch_write(
+			(&mut cpu::KERNEL_TRAP_FRAME[0]
+			 as *mut cpu::TrapFrame)
+			as usize,
+		);
+		cpu::KERNEL_TRAP_FRAME[0].hartid = 0;
 		let mtimecmp = 0x0200_4000 as *mut u64;
 		let mtime = 0x0200_bff8 as *const u64;
 		// The frequency given by QEMU is 10_000_000 Hz, so this sets

risc_v/ch8/src/process.rs

@@ -26,7 +26,7 @@ const STACK_PAGES: usize = 2;
 // regardless of where it is on the kernel heap.
 const STACK_ADDR: usize = 0xf_0000_0000;
 // All processes will have a defined starting point in virtual memory.
-const PROCESS_STARTING_ADDR: usize = 0x2000_0000;
+const PROCESS_STARTING_ADDR: usize = 0x8000_0000;
 
 // Here, we store a process list. It uses the global allocator
 // that we made before and its job is to store all processes.
@@ -94,6 +94,7 @@ pub fn init() -> usize {
 		// the address, and then move it right back in.
 		let pl = PROCESS_LIST.take().unwrap();
 		let p = pl.front().unwrap().frame;
+		let func_vaddr = pl.front().unwrap().program_counter;
 		let frame = &p as *const TrapFrame as usize;
 		mscratch_write(frame);
 		satp_write(build_satp(
@@ -107,7 +108,7 @@ pub fn init() -> usize {
 		PROCESS_LIST.replace(pl);
 		// Return the first instruction's address to execute.
 		// Since we use the MMU, all start here.
-		PROCESS_STARTING_ADDR
+		func_vaddr
 	}
 }
 
@@ -163,13 +164,15 @@ impl Process {
 	}
 	pub fn new_default(func: fn()) -> Self {
 		let func_addr = func as usize;
+		let func_vaddr = func_addr; //- 0x6000_0000;
+		// println!("func_addr = {:x} -> {:x}", func_addr, func_vaddr);
 		// We will convert NEXT_PID below into an atomic increment when
 		// we start getting into multi-hart processing. For now, we want
 		// a process. Get it to work, then improve it!
 		let mut ret_proc =
 			Process { frame:           TrapFrame::zero(),
 			          stack:           alloc(STACK_PAGES),
-			          program_counter: PROCESS_STARTING_ADDR,
+			          program_counter: func_vaddr,
 			          pid:             unsafe { NEXT_PID },
 			          root:            zalloc(1) as *mut Table,
 			          state:           ProcessState::Waiting,
@@ -207,21 +210,17 @@ impl Process {
 			    0,
 			);
 		}
-		// Map the program counter on the MMU
-		map(
-		    pt,
-		    PROCESS_STARTING_ADDR,
-		    func_addr,
-		    EntryBits::UserReadExecute.val(),
-		    0,
-		);
-		map(
-		    pt,
-		    PROCESS_STARTING_ADDR + 0x1001,
-		    func_addr + 0x1001,
-		    EntryBits::UserReadExecute.val(),
-		    0,
-		);
+		// Map the program counter on the MMU and other bits
+		for i in 0..=100 {
+			let modifier = i * 0x1000;
+			map(
+				pt,
+				func_vaddr + modifier,
+				func_addr + modifier,
+				EntryBits::UserReadWriteExecute.val(),
+				0,
+			);
+		}
 		ret_proc
 	}
 }

risc_v/ch8/src/trap.rs

@@ -118,6 +118,7 @@ extern "C" fn m_trap(epc: usize,
 			2 => {
 				// Illegal instruction
 				panic!("Illegal instruction CPU#{} -> 0x{:08x}: 0x{:08x}\n", hart, epc, tval);
+				while true {}
 			},
 			8 => {
 				// Environment (system) call from User mode
@@ -137,16 +138,19 @@ extern "C" fn m_trap(epc: usize,
 			12 => {
 				// Instruction page fault
 				println!("Instruction page fault CPU#{} -> 0x{:08x}: 0x{:08x}", hart, epc, tval);
+				while true {}
 				return_pc += 4;
 			},
 			13 => {
 				// Load page fault
 				println!("Load page fault CPU#{} -> 0x{:08x}: 0x{:08x}", hart, epc, tval);
+				while true {}
 				return_pc += 4;
 			},
 			15 => {
 				// Store page fault
 				println!("Store page fault CPU#{} -> 0x{:08x}: 0x{:08x}", hart, epc, tval);
+				while true {}
 				return_pc += 4;
 			},
 			_ => {