backported fixes from 256boss

[bootcensus] / src / intr.c

diff --git a/src/intr.c b/src/intr.c
index 1ace71e..2ec1f1b 100644 (file)
--- a/src/intr.c
+++ b/src/intr.c
@@ -1,4 +1,22 @@
+/*
+pcboot - bootable PC demo/game kernel
+Copyright (C) 2018  John Tsiombikas <nuclear@member.fsf.org>
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY, without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
 #include <stdio.h>
+#include "config.h"
 #include "intr.h"
 #include "desc.h"
 #include "segm.h"
@@ -37,12 +55,14 @@
 #define OCW2_EOI       (1 << 5)
 
 
-static void init_pic(int offset);
+void init_pic(void);
 static void gate_desc(desc_t *desc, uint16_t sel, uint32_t addr, int dpl, int type);
 
 /* defined in intr_asm.S */
 void set_idt(uint32_t addr, uint16_t limit);
 void intr_entry_default(void);
+void irq7_entry_check_spurious(void);
+void irq15_entry_check_spurious(void);
 
 /* the IDT (interrupt descriptor table) */
 static desc_t idt[256] __attribute__((aligned(8)));
@@ -73,10 +93,16 @@ void init_intr(void)
         */
 #include "intrtab.h"
 
+       /* change irq7 and irq15 to special entry points which first
+        * make sure we didn't get a spurious interrupt before proceeding
+        */
+       set_intr_entry(IRQ_TO_INTR(7), irq7_entry_check_spurious);
+       set_intr_entry(IRQ_TO_INTR(15), irq15_entry_check_spurious);
+
        /* initialize the programmable interrupt controller
         * setting up the maping of IRQs [0, 15] to interrupts [32, 47]
         */
-       init_pic(IRQ_OFFSET);
+       init_pic();
        eoi_pending = 0;
 }
 
@@ -91,7 +117,10 @@ struct intr_frame *get_intr_frame(void)
 /* set an interrupt handler function for a particular interrupt */
 void interrupt(int intr_num, intr_func_t func)
 {
+       int iflag = get_intr_flag();
+       disable_intr();
        intr_func[intr_num] = func;
+       set_intr_flag(iflag);
 }
 
 /* this function is called from all interrupt entry points
@@ -121,14 +150,19 @@ void dispatch_intr(struct intr_frame frm)
        }
 }
 
-static void init_pic(int offset)
+void init_pic(void)
+{
+       prog_pic(IRQ_OFFSET);
+}
+
+void prog_pic(int offs)
 {
        /* send ICW1 saying we'll follow with ICW4 later on */
        outb(ICW1_INIT | ICW1_ICW4_NEEDED, PIC1_CMD);
        outb(ICW1_INIT | ICW1_ICW4_NEEDED, PIC2_CMD);
        /* send ICW2 with IRQ remapping */
-       outb(offset, PIC1_DATA);
-       outb(offset + 8, PIC2_DATA);
+       outb(offs, PIC1_DATA);
+       outb(offs + 8, PIC2_DATA);
        /* send ICW3 to setup the master/slave relationship */
        /* ... set bit3 = 3rd interrupt input has a slave */
        outb(4, PIC1_DATA);
@@ -169,6 +203,49 @@ void set_intr_entry(int num, void (*handler)(void))
        gate_desc(idt + num, selector(SEGM_KCODE, 0), (uint32_t)handler, dpl, type);
 }
 
+void set_pic_mask(int pic, unsigned char mask)
+{
+       outb(mask, pic > 0 ? PIC2_DATA : PIC1_DATA);
+}
+
+unsigned char get_pic_mask(int pic)
+{
+       return inb(pic > 0 ? PIC2_DATA : PIC1_DATA);
+}
+
+void mask_irq(int irq)
+{
+       int port;
+       unsigned char mask;
+
+       if(irq < 8) {
+               port = PIC1_DATA;
+       } else {
+               port = PIC2_DATA;
+               irq -= 8;
+       }
+
+       mask = inb(port) | (1 << irq);
+       outb(mask, port);
+}
+
+void unmask_irq(int irq)
+{
+       int port;
+       unsigned char mask;
+
+       if(irq < 8) {
+               port = PIC1_DATA;
+       } else {
+               port = PIC2_DATA;
+               irq -= 8;
+       }
+
+       mask = inb(port) & ~(1 << irq);
+       outb(mask, port);
+}
+
+
 void end_of_irq(int irq)
 {
        int intr_state = get_intr_flag();
@@ -186,3 +263,10 @@ void end_of_irq(int irq)
 
        set_intr_flag(intr_state);
 }
+
+#ifdef ENABLE_GDB_STUB
+void exceptionHandler(int id, void (*func)())
+{
+       set_intr_entry(id, func);
+}
+#endif