From: Minep <zelong56@gmail.com>
Date: Tue, 3 May 2022 14:22:16 +0000 (+0100)
Subject: Implement (half) simple semaphore & mutex lock, and ...
X-Git-Url: https://scm.lunaixsky.com/lunaix-os.git/commitdiff_plain/a0655e5d30f3cdc73b1aaaa4825d8fae9f92ce4a?hp=9440be3a5115a91dcdf8dff05a361cac4b6cea29

Implement (half) simple semaphore & mutex lock, and ...
Use vga cursor.
Address the issue of spurious IRQ#1 which interference key hanlder when receiving the command response byte.
Refactoring and commentings.
---

diff --git a/lunaix-os/includes/lunaix/ds/mutex.h b/lunaix-os/includes/lunaix/ds/mutex.h
new file mode 100644
index 0000000..5e166e5
--- /dev/null
+++ b/lunaix-os/includes/lunaix/ds/mutex.h
@@ -0,0 +1,26 @@
+#ifndef __LUNAIX_MUTEX_H
+#define __LUNAIX_MUTEX_H
+
+#include "semaphore.h"
+
+// TODO: implement mutex lock
+
+typedef struct sem_t mutex_t;
+
+static inline void mutex_init(mutex_t *mutex) {
+    sem_init(mutex, 1);
+}
+
+static inline unsigned int mutex_on_hold(mutex_t *mutex) {
+    return !atomic_load(&mutex->counter);
+}
+
+static inline void mutex_lock(mutex_t *mutex) {
+    sem_wait(mutex);
+}
+
+static inline void mutex_unlock(mutex_t *mutex) {
+    sem_post(mutex);
+}
+
+#endif /* __LUNAIX_MUTEX_H */
diff --git a/lunaix-os/includes/lunaix/ds/semaphore.h b/lunaix-os/includes/lunaix/ds/semaphore.h
new file mode 100644
index 0000000..e202d14
--- /dev/null
+++ b/lunaix-os/includes/lunaix/ds/semaphore.h
@@ -0,0 +1,17 @@
+#ifndef __LUNAIX_SEMAPHORE_H
+#define __LUNAIX_SEMAPHORE_H
+
+#include <stdatomic.h>
+
+struct sem_t {
+    _Atomic unsigned int counter;
+    // FUTURE: might need a waiting list
+};
+
+void sem_init(struct sem_t *sem, unsigned int initial);
+
+void sem_wait(struct sem_t *sem);
+
+void sem_post(struct sem_t *sem);
+
+#endif /* __LUNAIX_SEMAPHORE_H */
diff --git a/lunaix-os/includes/lunaix/keyboard.h b/lunaix-os/includes/lunaix/keyboard.h
index c439b6f..7f13088 100644
--- a/lunaix-os/includes/lunaix/keyboard.h
+++ b/lunaix-os/includes/lunaix/keyboard.h
@@ -94,6 +94,6 @@ struct kdb_keyinfo_pkt {
     time_t timestamp;
 };
 
-struct kdb_keyinfo_pkt* kbd_try_read_one();
+int kbd_recv_key(struct kdb_keyinfo_pkt* key_event);
 
 #endif /* __LUNAIX_KEYBOARD_H */
diff --git a/lunaix-os/includes/lunaix/peripheral/ps2kbd.h b/lunaix-os/includes/lunaix/peripheral/ps2kbd.h
index a63ffdc..d373aa8 100644
--- a/lunaix-os/includes/lunaix/peripheral/ps2kbd.h
+++ b/lunaix-os/includes/lunaix/peripheral/ps2kbd.h
@@ -3,6 +3,8 @@
 
 #include <hal/io.h>
 #include <lunaix/keyboard.h>
+#include <lunaix/ds/mutex.h>
+
 
 #define PS2_PORT_ENC_DATA 0x60
 #define PS2_PORT_ENC_CMDREG 0x60
@@ -64,16 +66,14 @@ struct ps2_cmd_queue {
     struct ps2_cmd cmd_queue[PS2_CMD_QUEUE_SIZE];
     int queue_ptr;
     int queue_len;
-    // FIXME: replace lock with something specialized.
-    volatile char lock;
+    mutex_t mutex;
 };
 
 struct ps2_key_buffer {
     struct kdb_keyinfo_pkt buffer[PS2_KBD_RECV_BUFFER_SIZE];
     int read_ptr;
     int buffered_len;
-    // FIXME: replace lock with something specialized.
-    volatile char lock;
+    mutex_t mutex;
 };
 
 /**
diff --git a/lunaix-os/includes/lunaix/tty/tty.h b/lunaix-os/includes/lunaix/tty/tty.h
index 28ad83d..cbb3924 100644
--- a/lunaix-os/includes/lunaix/tty/tty.h
+++ b/lunaix-os/includes/lunaix/tty/tty.h
@@ -52,5 +52,9 @@ tty_get_cpos(unsigned int* x, unsigned int* y);
 vga_attribute
 tty_get_theme();
 
+void tty_set_cursor(unsigned char x, unsigned char y);
+
+void tty_sync_cursor();
+
 
 #endif /* __LUNAIX_TTY_H */
diff --git a/lunaix-os/kernel/ds/semaphore.c b/lunaix-os/kernel/ds/semaphore.c
new file mode 100644
index 0000000..21d0e33
--- /dev/null
+++ b/lunaix-os/kernel/ds/semaphore.c
@@ -0,0 +1,17 @@
+#include <lunaix/ds/semaphore.h>
+
+void sem_init(struct sem_t *sem, unsigned int initial) {
+    sem->counter = ATOMIC_VAR_INIT(initial);
+}
+
+void sem_wait(struct sem_t *sem) {
+    while (!atomic_load(&sem->counter)) {
+        // TODO: yield the cpu
+    }
+    atomic_fetch_sub(&sem->counter, 1);
+}
+
+void sem_post(struct sem_t *sem) {
+    atomic_fetch_add(&sem->counter, 1);
+    // TODO: wake up a thread
+}
\ No newline at end of file
diff --git a/lunaix-os/kernel/k_main.c b/lunaix-os/kernel/k_main.c
index fe5645f..c3819d9 100644
--- a/lunaix-os/kernel/k_main.c
+++ b/lunaix-os/kernel/k_main.c
@@ -55,16 +55,16 @@ _kernel_main()
 
     // timer_run_second(1, test_timer, NULL, TIMER_MODE_PERIODIC);
 
+    struct kdb_keyinfo_pkt keyevent;
     while (1)
     {
-        struct kdb_keyinfo_pkt* keyevent = kbd_try_read_one();
-        if (!keyevent) {
+        if (!kbd_recv_key(&keyevent)) {
             continue;
         }
-        if ((keyevent->state & KBD_KEY_FPRESSED) && (keyevent->keycode & 0xff00) <= KEYPAD) {
-            tty_put_char((char)(keyevent->keycode & 0x00ff));
+        if ((keyevent.state & KBD_KEY_FPRESSED) && (keyevent.keycode & 0xff00) <= KEYPAD) {
+            tty_put_char((char)(keyevent.keycode & 0x00ff));
+            tty_sync_cursor();
         }
-        lxfree(keyevent);
     }
 
     spin();
diff --git a/lunaix-os/kernel/mm/kalloc.c b/lunaix-os/kernel/mm/kalloc.c
index e9f0564..16c1d82 100644
--- a/lunaix-os/kernel/mm/kalloc.c
+++ b/lunaix-os/kernel/mm/kalloc.c
@@ -23,6 +23,7 @@
 
 extern uint8_t __kernel_heap_start;
 
+// FIXME: This should go to PCB once we're started to support multitasking
 static heap_context_t __kalloc_kheap;
 
 void*
diff --git a/lunaix-os/kernel/peripheral/ps2kbd.c b/lunaix-os/kernel/peripheral/ps2kbd.c
index fc4151a..4e7fb63 100644
--- a/lunaix-os/kernel/peripheral/ps2kbd.c
+++ b/lunaix-os/kernel/peripheral/ps2kbd.c
@@ -3,14 +3,13 @@
 #include <lunaix/timer.h>
 #include <lunaix/common.h>
 #include <lunaix/syslog.h>
-#include <lunaix/mm/kalloc.h>
 
 #include <hal/cpu.h>
-
 #include <arch/x86/interrupts.h>
-#include <stdint.h>
 #include <klibc/string.h>
 
+#include <stdint.h>
+
 #define PS2_DEV_CMD_MAX_ATTEMPTS 5
 
 LOG_MODULE("PS2KBD");
@@ -68,20 +67,18 @@ static kbd_keycode_t scancode_set2_shift[] = {
 #define KBD_STATE_KWAIT         0x00
 #define KBD_STATE_KSPECIAL      0x01
 #define KBD_STATE_KRELEASED     0x02
-// #define KBD_STATE_CMDPROCS      0x80
+#define KBD_STATE_CMDPROCS      0x40
 
 void intr_ps2_kbd_handler(const isr_param* param);
 static struct kdb_keyinfo_pkt* ps2_keybuffer_next_write();
 
 // TODO: Abstract the bounded buffer out.
 void ps2_device_post_cmd(char cmd, char arg) {
-    // 不需要任何的类似lock cmpxchgl的骚操作。
-    // 这条赋值表达式最多涉及一个内存引用（e.g., movl $1, (cmd_q.lock)），因此是原子的。
-    cmd_q.lock = 1;
+    mutex_lock(&cmd_q.mutex);
     int index = (cmd_q.queue_ptr + cmd_q.queue_len) % PS2_CMD_QUEUE_SIZE;
     if (index == cmd_q.queue_ptr && cmd_q.queue_len) {
         // 队列已满！
-        cmd_q.lock = 0;
+        mutex_unlock(&cmd_q.mutex);
         return;
     }
 
@@ -91,7 +88,7 @@ void ps2_device_post_cmd(char cmd, char arg) {
     cmd_q.queue_len++;
 
     // 释放锁，同理。
-    cmd_q.lock = 0;
+    mutex_unlock(&cmd_q.mutex);
 }
 
 void ps2_kbd_init() {
@@ -99,6 +96,11 @@ void ps2_kbd_init() {
     memset(&cmd_q, 0, sizeof(cmd_q));
     memset(&key_buf, 0, sizeof(key_buf));
     memset(&kbd_state, 0, sizeof(kbd_state));
+    
+    mutex_init(&cmd_q.mutex);
+    mutex_init(&key_buf.mutex);
+
+
     kbd_state.translation_table = scancode_set2;
     kbd_state.state = KBD_STATE_KWAIT;
 
@@ -163,11 +165,10 @@ void ps2_process_cmd(void* arg) {
     // 因此，我们这里仅仅进行判断。
     // 会不会产生指令堆积？不会，因为指令发送的频率远远低于指令队列清空的频率。在目前，我们发送的唯一指令
     // 就只是用来开关键盘上的LED灯（如CAPSLOCK）。
-    if (!cmd_q.queue_len || cmd_q.lock) {
+    if (mutex_on_hold(&cmd_q.mutex) || !cmd_q.queue_len) {
         return;
     }
 
-    // kbd_state.state |= KBD_STATE_CMDPROCS;
     // 处理队列排头的指令
     struct ps2_cmd *pending_cmd = &cmd_q.cmd_queue[cmd_q.queue_ptr];
     char result;
@@ -178,6 +179,7 @@ void ps2_process_cmd(void* arg) {
     // 则尝试最多五次
     do {
         result = ps2_issue_dev_cmd(pending_cmd->cmd, pending_cmd->arg);
+        kbd_state.state += KBD_STATE_CMDPROCS;
         attempts++;
     } while(result == PS2_RESULT_NAK && attempts < PS2_DEV_CMD_MAX_ATTEMPTS);
     
@@ -207,7 +209,7 @@ void kbd_buffer_key_event(kbd_keycode_t key, uint8_t scancode, kbd_kstate_t stat
         state = state | kbd_state.key_state;
         key = key & (0xffdf | -('a' > key || key > 'z' || !(state & KBD_KEY_FCAPSLKED)));
 
-        if (!key_buf.lock) {
+        if (!mutex_on_hold(&key_buf.mutex)) {
             struct kdb_keyinfo_pkt* keyevent_pkt = ps2_keybuffer_next_write();
             *keyevent_pkt = (struct kdb_keyinfo_pkt) {
                 .keycode = key,
@@ -242,18 +244,14 @@ void intr_ps2_kbd_handler(const isr_param* param) {
      * 那么当ps2_process_cmd执行完后（内嵌在#APIC_TIMER_IV），CPU返回EOI给APIC，APIC紧接着将排在队里的IRQ#1发送给CPU
      * 造成误触发。也就是说，我们此时读入的scancode实则上是上一个指令的返回代码。
      * 
-     * Problem 1:
+     * Problem 1 (Fixed):
      *      但是这种方法有个问题，那就是，假若我们的某一个命令失败了一次，ps/2给出0xfe，我们重传，ps/2收到指令并给出0xfa。
      *  那么这样一来，将会由两个连续的IRQ#1产生。而APIC是最多可以缓存两个IRQ，于是我们就会漏掉一个IRQ，依然会误触发。
+     * Solution:
+     *      累加掩码 ;)
      */
-    // FIXME: Address Problem #1
-    // if ((kbd_state.state & KBD_STATE_CMDPROCS)) {
-    //     kbd_state.state &= ~KBD_STATE_CMDPROCS;
-    //     return;
-    // }
-
-    // 目前还是使用该方法。。。
-    if (scancode >= 0xfa) {
+    if ((kbd_state.state & 0xc0)) {
+        kbd_state.state -= KBD_STATE_CMDPROCS;
         return;
     }
     
@@ -333,22 +331,20 @@ static void ps2_post_cmd(uint8_t port, char cmd, uint16_t arg) {
     }
 }
 
-struct kdb_keyinfo_pkt* kbd_try_read_one() {
+int kbd_recv_key(struct kdb_keyinfo_pkt* key_event) {
     if (!key_buf.buffered_len) {
-        return NULL;
+        return 0;
     }
-    key_buf.lock = 1;
-    struct kdb_keyinfo_pkt* pkt_copy = 
-        (struct kdb_keyinfo_pkt*) lxmalloc(sizeof(struct kdb_keyinfo_pkt));
+    mutex_lock(&key_buf.mutex);
 
     struct kdb_keyinfo_pkt* pkt_current = &key_buf.buffer[key_buf.read_ptr];
 
-    *pkt_copy = *pkt_current;
+    *key_event = *pkt_current;
     key_buf.buffered_len--;
     key_buf.read_ptr = (key_buf.read_ptr + 1) % PS2_KBD_RECV_BUFFER_SIZE;
 
-    key_buf.lock = 0;
-    return pkt_copy;
+    mutex_unlock(&key_buf.mutex);
+    return 1;
 }
 
 static struct kdb_keyinfo_pkt* ps2_keybuffer_next_write() {
diff --git a/lunaix-os/kernel/tty/tty.c b/lunaix-os/kernel/tty/tty.c
index 4a20a77..c779ed5 100644
--- a/lunaix-os/kernel/tty/tty.c
+++ b/lunaix-os/kernel/tty/tty.c
@@ -2,6 +2,7 @@
 #include <lunaix/tty/tty.h>
 #include <lunaix/common.h>
 #include <stdint.h>
+#include <hal/io.h>
 
 #define TTY_WIDTH 80
 #define TTY_HEIGHT 25
@@ -11,11 +12,17 @@ static vga_attribute* tty_vga_buffer = (vga_attribute*)VGA_BUFFER_PADDR;
 static vga_attribute tty_theme_color = VGA_COLOR_BLACK;
 
 static uint32_t tty_x = 0;
-static uint16_t tty_y = 0;
+static uint32_t tty_y = 0;
 
 void tty_init(void* vga_buf) {
     tty_vga_buffer = (vga_attribute*)vga_buf;
     tty_clear();
+
+    io_outb(0x3D4, 0x0A);
+	io_outb(0x3D5, (io_inb(0x3D5) & 0xC0) | 13);
+ 
+	io_outb(0x3D4, 0x0B);
+	io_outb(0x3D5, (io_inb(0x3D5) & 0xE0) | 15);
 }
 
 void tty_set_buffer(void* vga_buf) {
@@ -60,6 +67,22 @@ tty_put_char(char chr)
     }
 }
 
+void tty_sync_cursor() {
+    tty_set_cursor(tty_x, tty_y);
+}
+
+
+void tty_set_cursor(uint8_t x, uint8_t y) {
+    if (x >= TTY_WIDTH || y >= TTY_HEIGHT) {
+        x = y = 0;
+    }
+    uint32_t pos = y * TTY_WIDTH + x;
+    io_outb(0x3D4, 14);
+    io_outb(0x3D5, pos / 256);
+    io_outb(0x3D4, 15);
+    io_outb(0x3D5, pos % 256);
+}
+
 void
 tty_put_str(char* str)
 {
@@ -67,6 +90,7 @@ tty_put_str(char* str)
         tty_put_char(*str);
         str++;
     }
+    tty_sync_cursor();
 }
 
 void