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- /*
- * librm: a library for interfacing to real-mode code
- *
- * Michael Brown <mbrown@fensystems.co.uk>
- *
- */
-
- FILE_LICENCE ( GPL2_OR_LATER );
-
- #include <stdint.h>
- #include <ipxe/profile.h>
- #include <realmode.h>
- #include <pic8259.h>
-
- /*
- * This file provides functions for managing librm.
- *
- */
-
- /** The interrupt wrapper */
- extern char interrupt_wrapper[];
-
- /** The interrupt vectors */
- static struct interrupt_vector intr_vec[NUM_INT];
-
- /** The interrupt descriptor table */
- struct interrupt_descriptor idt[NUM_INT] __attribute__ (( aligned ( 16 ) ));
-
- /** The interrupt descriptor table register */
- struct idtr idtr = {
- .limit = ( sizeof ( idt ) - 1 ),
- };
-
- /** Timer interrupt profiler */
- static struct profiler timer_irq_profiler __profiler = { .name = "irq.timer" };
-
- /** Other interrupt profiler */
- static struct profiler other_irq_profiler __profiler = { .name = "irq.other" };
-
- /**
- * Allocate space on the real-mode stack and copy data there from a
- * user buffer
- *
- * @v data User buffer
- * @v size Size of stack data
- * @ret sp New value of real-mode stack pointer
- */
- uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size ) {
- userptr_t rm_stack;
- rm_sp -= size;
- rm_stack = real_to_user ( rm_ss, rm_sp );
- memcpy_user ( rm_stack, 0, data, 0, size );
- return rm_sp;
- };
-
- /**
- * Deallocate space on the real-mode stack, optionally copying back
- * data to a user buffer.
- *
- * @v data User buffer
- * @v size Size of stack data
- */
- void remove_user_from_rm_stack ( userptr_t data, size_t size ) {
- if ( data ) {
- userptr_t rm_stack = real_to_user ( rm_ss, rm_sp );
- memcpy_user ( rm_stack, 0, data, 0, size );
- }
- rm_sp += size;
- };
-
- /**
- * Set interrupt vector
- *
- * @v intr Interrupt number
- * @v vector Interrupt vector, or NULL to disable
- */
- void set_interrupt_vector ( unsigned int intr, void *vector ) {
- struct interrupt_descriptor *idte;
-
- idte = &idt[intr];
- idte->segment = VIRTUAL_CS;
- idte->attr = ( vector ? ( IDTE_PRESENT | IDTE_TYPE_IRQ32 ) : 0 );
- idte->low = ( ( ( uint32_t ) vector ) & 0xffff );
- idte->high = ( ( ( uint32_t ) vector ) >> 16 );
- }
-
- /**
- * Initialise interrupt descriptor table
- *
- */
- void init_idt ( void ) {
- struct interrupt_vector *vec;
- unsigned int intr;
-
- /* Initialise the interrupt descriptor table and interrupt vectors */
- for ( intr = 0 ; intr < NUM_INT ; intr++ ) {
- vec = &intr_vec[intr];
- vec->pushal = PUSHAL_INSN;
- vec->movb = MOVB_INSN;
- vec->intr = intr;
- vec->jmp = JMP_INSN;
- vec->offset = ( ( uint32_t ) interrupt_wrapper -
- ( uint32_t ) vec->next );
- set_interrupt_vector ( intr, vec );
- }
- DBGC ( &intr_vec[0], "INTn vector at %p+%xn (phys %#lx+%xn)\n",
- intr_vec, sizeof ( intr_vec[0] ),
- virt_to_phys ( intr_vec ), sizeof ( intr_vec[0] ) );
-
- /* Initialise the interrupt descriptor table register */
- idtr.base = virt_to_phys ( idt );
- }
-
- /**
- * Determine interrupt profiler (for debugging)
- *
- * @v intr Interrupt number
- * @ret profiler Profiler
- */
- static struct profiler * interrupt_profiler ( int intr ) {
-
- switch ( intr ) {
- case IRQ_INT ( 0 ) :
- return &timer_irq_profiler;
- default:
- return &other_irq_profiler;
- }
- }
-
- /**
- * Interrupt handler
- *
- * @v intr Interrupt number
- */
- void __attribute__ (( cdecl, regparm ( 1 ) )) interrupt ( int intr ) {
- struct profiler *profiler = interrupt_profiler ( intr );
- uint32_t discard_eax;
-
- /* Reissue interrupt in real mode */
- profile_start ( profiler );
- __asm__ __volatile__ ( REAL_CODE ( "movb %%al, %%cs:(1f + 1)\n\t"
- "\n1:\n\t"
- "int $0x00\n\t" )
- : "=a" ( discard_eax ) : "0" ( intr ) );
- profile_stop ( profiler );
- profile_exclude ( profiler );
- }
-
- PROVIDE_UACCESS_INLINE ( librm, phys_to_user );
- PROVIDE_UACCESS_INLINE ( librm, user_to_phys );
- PROVIDE_UACCESS_INLINE ( librm, virt_to_user );
- PROVIDE_UACCESS_INLINE ( librm, user_to_virt );
- PROVIDE_UACCESS_INLINE ( librm, userptr_add );
- PROVIDE_UACCESS_INLINE ( librm, memcpy_user );
- PROVIDE_UACCESS_INLINE ( librm, memmove_user );
- PROVIDE_UACCESS_INLINE ( librm, memset_user );
- PROVIDE_UACCESS_INLINE ( librm, strlen_user );
- PROVIDE_UACCESS_INLINE ( librm, memchr_user );
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