From 426da8be0db33405b0cfe53108b65040623972f0 Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Sat, 11 Jun 2022 19:08:18 +0300
Subject: continue documentation

---
 arch/riscv64/kernel/cpu.c   | 10 +++++++++-
 arch/riscv64/kernel/entry.S | 11 ++++++-----
 arch/riscv64/kernel/proc.c  |  6 +++---
 3 files changed, 18 insertions(+), 9 deletions(-)

(limited to 'arch/riscv64')

diff --git a/arch/riscv64/kernel/cpu.c b/arch/riscv64/kernel/cpu.c
index 0558040..91b39b6 100644
--- a/arch/riscv64/kernel/cpu.c
+++ b/arch/riscv64/kernel/cpu.c
@@ -3,9 +3,17 @@
  * riscv64 implementation of cpu handling.
  */
 
+#include <apos/tcb.h>
 #include <arch/cpu.h>
 
 id_t cpu_id()
 {
-	return 0; /* VERY MUCH TEMP */
+	/* yes, slightly weird situation where cur_tcb() call cpu_id() which
+	 * gets the current tcb and returns the cpu id in the tcb, so that that
+	 * id can be used to get the tcb we want. I might try to work out
+	 * something slightly smarter, although this is likely not going to have
+	 * basically any kind of importance for perfomance. */
+	struct tcb *t;
+	__asm__ volatile ("mv %0, tp\n" : "=r" (t) ::);
+	return t->cpu_id;
 }
diff --git a/arch/riscv64/kernel/entry.S b/arch/riscv64/kernel/entry.S
index a5427a7..ee7b10f 100644
--- a/arch/riscv64/kernel/entry.S
+++ b/arch/riscv64/kernel/entry.S
@@ -25,8 +25,8 @@ _save_context:
 	sr	sp, offsetof_sp(tp)
 	mv	sp, tp
 
-	/* set scratch to 0 and move thread pointer back */
-	csrrw tp, CSR_SSCRATCH, x0
+	/* move thread pointer back */
+	csrrw tp, CSR_SSCRATCH, tp
 
 	/* save registers */
 	sr      ra, offsetof_ra(sp)
@@ -60,6 +60,10 @@ _save_context:
 	sr      t5, offsetof_t5(sp)
 	sr      t6, offsetof_t6(sp)
 
+	/* get current tcb into tp and set scratch to 0 so we can figure out if
+	 * exception occured in kernel or userspace */
+	csrrw tp, CSR_SSCRATCH, x0
+
 	/* load supervisor cause */
 	csrr s4, CSR_SCAUSE
 	/* interrupts fall through, exceptions jump */
@@ -85,9 +89,6 @@ handle_syscall:
 	/* TODO: is a whole function call necessary? */
 	mv	s0, a0
 	mv	s1, a1
-	/* get current tcb */
-	call cur_tcb
-	mv	tp, a0
 	/* get associated kernel stack */
 	mv	sp, tp
 	addi	sp, sp, -sizeof_registers
diff --git a/arch/riscv64/kernel/proc.c b/arch/riscv64/kernel/proc.c
index 09d694f..a85ae6f 100644
--- a/arch/riscv64/kernel/proc.c
+++ b/arch/riscv64/kernel/proc.c
@@ -33,15 +33,15 @@ stat_t set_ipc(struct tcb *t, id_t pid, id_t tid)
 	return OK;
 }
 
-stat_t set_thread(struct tcb *t, vm_t stack)
+stat_t set_thread(struct tcb *t)
 {
 	/* get location of registers in memory */
 	/** \todo check alignment, should be fine but just to be sure */
 	struct riscv_regs *r = (struct riscv_regs *)(--t);
 
 	/* insert important values into register slots */
-	r->sp = (long)stack;
-	r->tp = (long)t;
+	r->sp = (long)t->thread_stack_top;
+	r->tp = (long)t->thread_storage;
 
 	return OK;
 }
-- 
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