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#include <arch.h>
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#include <arch.h>
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#include <arch/context.h>   /* SP_DELTA */
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#include <arch/context.h>   /* SP_DELTA */
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#include <arch/debugger.h>
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#include <arch/debugger.h>
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#include <arch/pm.h>
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#include <arch/pm.h>
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#include <arch/asm.h>
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#include <arch/asm.h>
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#include <adt/bitmap.h>
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/** Perform ia32 specific tasks needed before the new task is run.
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/** Perform ia32 specific tasks needed before the new task is run.
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 *
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 *
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 * Interrupts are disabled.
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 * Interrupts are disabled.
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 */
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 */
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void before_task_runs_arch(void)
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void before_task_runs_arch(void)
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{
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{
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    size_t iomap_size;
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    count_t bits;
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    ptr_16_32_t cpugdtr;
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    ptr_16_32_t cpugdtr;
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    descriptor_t *gdt_p;
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    descriptor_t *gdt_p;
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    /*
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    /*
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     * Switch the I/O Permission Bitmap, if necessary.
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     * Switch the I/O Permission Bitmap, if necessary.
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     */
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     */
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    /* First, copy the I/O Permission Bitmap. */
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    /* First, copy the I/O Permission Bitmap. */
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    spinlock_lock(&TASK->lock);
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    spinlock_lock(&TASK->lock);
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    iomap_size = TASK->arch.iomap_size;
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    if ((bits = TASK->arch.iomap.bits)) {
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    if (iomap_size) {
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        bitmap_t iomap;
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        ASSERT(TASK->arch.iomap);
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        ASSERT(TASK->arch.iomap.map);
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        bitmap_initialize(&iomap, CPU->arch.tss->iomap, TSS_IOMAP_SIZE * 8);
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        memcpy(CPU->arch.tss->iomap, TASK->arch.iomap, iomap_size);
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        bitmap_copy(&iomap, &TASK->arch.iomap, TASK->arch.iomap.bits);
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        /*
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         * It is safe to set the trailing four bits because of the extra
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         * convenience byte in TSS_IOMAP_SIZE.
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         */
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        CPU->arch.tss->iomap[iomap_size] = 0xff;    /* terminating byte */
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        bitmap_set_range(&iomap, TASK->arch.iomap.bits, 4);
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    }
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    }
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    spinlock_unlock(&TASK->lock);  
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    spinlock_unlock(&TASK->lock);
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    /* Second, adjust TSS segment limit. */
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    /* Second, adjust TSS segment limit. */
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    gdtr_store(&cpugdtr);
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    gdtr_store(&cpugdtr);
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    gdt_p = (descriptor_t *) cpugdtr.base;
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    gdt_p = (descriptor_t *) cpugdtr.base;
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    gdt_setlimit(&gdt_p[TSS_DES], TSS_BASIC_SIZE + iomap_size - 1);
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    gdt_setlimit(&gdt_p[TSS_DES], TSS_BASIC_SIZE + BITS2BYTES(bits) - 1);
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    gdtr_load(&cpugdtr);
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    gdtr_load(&cpugdtr);
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}
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}
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/** Perform ia32 specific tasks needed before the new thread is scheduled.
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/** Perform ia32 specific tasks needed before the new thread is scheduled.
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 *
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 *