mirror of https://github.com/ipxe/ipxe.git
159 lines
4.0 KiB
C
159 lines
4.0 KiB
C
/*
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* librm: a library for interfacing to real-mode code
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*
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* Michael Brown <mbrown@fensystems.co.uk>
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*
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*/
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FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
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#include <stdint.h>
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#include <ipxe/profile.h>
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#include <realmode.h>
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#include <pic8259.h>
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/*
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* This file provides functions for managing librm.
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*
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*/
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/** The interrupt wrapper */
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extern char interrupt_wrapper[];
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/** The interrupt vectors */
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static struct interrupt_vector intr_vec[NUM_INT];
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/** The interrupt descriptor table */
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struct interrupt_descriptor idt[NUM_INT] __attribute__ (( aligned ( 16 ) ));
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/** The interrupt descriptor table register */
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struct idtr idtr = {
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.limit = ( sizeof ( idt ) - 1 ),
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};
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/** Timer interrupt profiler */
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static struct profiler timer_irq_profiler __profiler = { .name = "irq.timer" };
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/** Other interrupt profiler */
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static struct profiler other_irq_profiler __profiler = { .name = "irq.other" };
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/**
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* Allocate space on the real-mode stack and copy data there from a
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* user buffer
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*
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* @v data User buffer
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* @v size Size of stack data
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* @ret sp New value of real-mode stack pointer
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*/
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uint16_t copy_user_to_rm_stack ( userptr_t data, size_t size ) {
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userptr_t rm_stack;
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rm_sp -= size;
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rm_stack = real_to_user ( rm_ss, rm_sp );
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memcpy_user ( rm_stack, 0, data, 0, size );
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return rm_sp;
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};
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/**
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* Deallocate space on the real-mode stack, optionally copying back
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* data to a user buffer.
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*
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* @v data User buffer
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* @v size Size of stack data
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*/
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void remove_user_from_rm_stack ( userptr_t data, size_t size ) {
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if ( data ) {
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userptr_t rm_stack = real_to_user ( rm_ss, rm_sp );
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memcpy_user ( rm_stack, 0, data, 0, size );
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}
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rm_sp += size;
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};
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/**
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* Set interrupt vector
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*
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* @v intr Interrupt number
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* @v vector Interrupt vector, or NULL to disable
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*/
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void set_interrupt_vector ( unsigned int intr, void *vector ) {
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struct interrupt_descriptor *idte;
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idte = &idt[intr];
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idte->segment = VIRTUAL_CS;
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idte->attr = ( vector ? ( IDTE_PRESENT | IDTE_TYPE_IRQ32 ) : 0 );
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idte->low = ( ( ( uint32_t ) vector ) & 0xffff );
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idte->high = ( ( ( uint32_t ) vector ) >> 16 );
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}
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/**
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* Initialise interrupt descriptor table
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*
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*/
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void init_idt ( void ) {
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struct interrupt_vector *vec;
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unsigned int intr;
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/* Initialise the interrupt descriptor table and interrupt vectors */
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for ( intr = 0 ; intr < NUM_INT ; intr++ ) {
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vec = &intr_vec[intr];
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vec->pushal = PUSHAL_INSN;
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vec->movb = MOVB_INSN;
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vec->intr = intr;
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vec->jmp = JMP_INSN;
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vec->offset = ( ( uint32_t ) interrupt_wrapper -
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( uint32_t ) vec->next );
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set_interrupt_vector ( intr, vec );
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}
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DBGC ( &intr_vec[0], "INTn vector at %p+%zxn (phys %#lx+%zxn)\n",
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intr_vec, sizeof ( intr_vec[0] ),
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virt_to_phys ( intr_vec ), sizeof ( intr_vec[0] ) );
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/* Initialise the interrupt descriptor table register */
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idtr.base = virt_to_phys ( idt );
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}
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/**
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* Determine interrupt profiler (for debugging)
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*
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* @v intr Interrupt number
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* @ret profiler Profiler
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*/
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static struct profiler * interrupt_profiler ( int intr ) {
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switch ( intr ) {
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case IRQ_INT ( 0 ) :
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return &timer_irq_profiler;
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default:
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return &other_irq_profiler;
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}
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}
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/**
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* Interrupt handler
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*
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* @v intr Interrupt number
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*/
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void __attribute__ (( cdecl, regparm ( 1 ) )) interrupt ( int intr ) {
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struct profiler *profiler = interrupt_profiler ( intr );
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uint32_t discard_eax;
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/* Reissue interrupt in real mode */
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profile_start ( profiler );
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__asm__ __volatile__ ( REAL_CODE ( "movb %%al, %%cs:(1f + 1)\n\t"
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"\n1:\n\t"
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"int $0x00\n\t" )
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: "=a" ( discard_eax ) : "0" ( intr ) );
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profile_stop ( profiler );
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profile_exclude ( profiler );
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}
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PROVIDE_UACCESS_INLINE ( librm, phys_to_user );
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PROVIDE_UACCESS_INLINE ( librm, user_to_phys );
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PROVIDE_UACCESS_INLINE ( librm, virt_to_user );
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PROVIDE_UACCESS_INLINE ( librm, user_to_virt );
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PROVIDE_UACCESS_INLINE ( librm, userptr_add );
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PROVIDE_UACCESS_INLINE ( librm, memcpy_user );
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PROVIDE_UACCESS_INLINE ( librm, memmove_user );
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PROVIDE_UACCESS_INLINE ( librm, memset_user );
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PROVIDE_UACCESS_INLINE ( librm, strlen_user );
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PROVIDE_UACCESS_INLINE ( librm, memchr_user );
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