Changeset f619ec11 in mainline for kernel/arch/ia32

Timestamp:

2007-02-03T21:26:54Z (18 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

cf5ddf6

Parents:

80bcaed

Message:

When clock() is called by an external interrupt dispatched by the IRQ dispatcher,
no spinlock can be held or the kernel will not be preemptive. This fixes Ticket #24.

Formating and indentation fixes.

Location:

kernel/arch/ia32/src

Files:

• drivers/i8254.c (modified) (2 diffs)
• drivers/i8259.c (modified) (2 diffs)
• ia32.c (modified) (1 diff)
• interrupt.c (modified) (1 diff)
• smp/smp.c (modified) (2 diffs)

kernel/arch/ia32/src/drivers/i8254.c

@@ -69 +69 @@
 static void i8254_irq_handler(irq_t *irq, void *arg, ...)
 {
+        /*
+         * This IRQ is responsible for kernel preemption.
+         * Nevertheless, we are now holding a spinlock which prevents
+         * preemption. For this particular IRQ, we don't need the
+         * lock. We just release it, call clock() and then reacquire it again.
+         */
+        spinlock_unlock(&irq->lock);
         clock();
+        spinlock_lock(&irq->lock);
 }
 
@@ -137 +145 @@
         o2 |= inb(CLK_PORT1) << 8;
 
-        CPU->delay_loop_const = ((MAGIC_NUMBER*LOOPS)/1000) / ((t1-t2)-(o1-o2)) + (((MAGIC_NUMBER*LOOPS)/1000) % ((t1-t2)-(o1-o2)) ? 1 : 0);
+        CPU->delay_loop_const =
+            ((MAGIC_NUMBER * LOOPS) / 1000) / ((t1 - t2) - (o1 - o2)) +
+            (((MAGIC_NUMBER * LOOPS) / 1000) % ((t1 - t2) - (o1 - o2)) ? 1 : 0);
 
         clk1 = get_cycle();

kernel/arch/ia32/src/drivers/i8259.c

@@ -87 +87 @@
 
         pic_disable_irqs(0xffff);               /* disable all irq's */
-        pic_enable_irqs(1<<IRQ_PIC1);           /* but enable pic1 */
+        pic_enable_irqs(1 << IRQ_PIC1);         /* but enable pic1 */
 }
 
@@ -120 +120 @@
 void pic_eoi(void)
 {
-        outb(0x20,0x20);
-        outb(0xa0,0x20);
+        outb(0x20, 0x20);
+        outb(0xa0, 0x20);
 }
 

kernel/arch/ia32/src/ia32.c

@@ -119 +119 @@
                 memory_print_map();
                 
-                #ifdef CONFIG_SMP
+#ifdef CONFIG_SMP
                 acpi_init();
-                #endif /* CONFIG_SMP */
+#endif /* CONFIG_SMP */
         }
 }

kernel/arch/ia32/src/interrupt.c

@@ -141 +141 @@
 {
         uint32_t mxcsr;
-        asm
-        (
+        asm (
                 "stmxcsr %0;\n"
                 :"=m"(mxcsr)
         );
         fault_if_from_uspace(istate, "SIMD FP exception(19), MXCSR: %#zx",
-                             (unative_t)mxcsr);
+            (unative_t)mxcsr);
 
         decode_istate(istate);

kernel/arch/ia32/src/smp/smp.c

@@ -113 +113 @@
          * Set the warm-reset vector to the real-mode address of 4K-aligned ap_boot()
          */
-        *((uint16_t *) (PA2KA(0x467+0))) =  ((uintptr_t) ap_boot) >> 4; /* segment */
-        *((uint16_t *) (PA2KA(0x467+2))) =  0;                          /* offset */
+        *((uint16_t *) (PA2KA(0x467 + 0))) =  ((uintptr_t) ap_boot) >> 4;       /* segment */
+        *((uint16_t *) (PA2KA(0x467 + 2))) =  0;                                /* offset */
         
         /*
@@ -120 +120 @@
          * BIOS will not do the POST after the INIT signal.
          */
-        outb(0x70,0xf);
-        outb(0x71,0xa);
+        outb(0x70, 0xf);
+        outb(0x71, 0xa);
 
         pic_disable_irqs(0xffff);