/*
* librm: a library for interfacing to real-mode code
*
* Michael Brown <mbrown@fensystems.co.uk>
*
*/
FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <stdint.h>
#include <strings.h>
#include <assert.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 32-bit interrupt descriptor table */
static struct interrupt32_descriptor
idt32[NUM_INT] __attribute__ (( aligned ( 16 ) ));
/** The 32-bit interrupt descriptor table register */
struct idtr32 idtr32 = {
.limit = ( sizeof ( idt32 ) - 1 ),
};
/** The 64-bit interrupt descriptor table */
static struct interrupt64_descriptor
idt64[NUM_INT] __attribute__ (( aligned ( 16 ) ));
/** The interrupt descriptor table register */
struct idtr64 idtr64 = {
.limit = ( sizeof ( idt64 ) - 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 interrupt32_descriptor *idte32;
struct interrupt64_descriptor *idte64;
intptr_t addr = ( ( intptr_t ) vector );
/* Populate 32-bit interrupt descriptor */
idte32 = &idt32[intr];
idte32->segment = VIRTUAL_CS;
idte32->attr = ( vector ? ( IDTE_PRESENT | IDTE_TYPE_IRQ32 ) : 0 );
idte32->low = ( addr >> 0 );
idte32->high = ( addr >> 16 );
/* Populate 64-bit interrupt descriptor, if applicable */
if ( sizeof ( physaddr_t ) > sizeof ( uint32_t ) ) {
idte64 = &idt64[intr];
idte64->segment = LONG_CS;
idte64->attr = ( vector ?
( IDTE_PRESENT | IDTE_TYPE_IRQ64 ) : 0 );
idte64->low = ( addr >> 0 );
idte64->mid = ( addr >> 16 );
idte64->high = ( ( ( uint64_t ) addr ) >> 32 );
}
}
/**
* 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->push = PUSH_INSN;
vec->movb = MOVB_INSN;
vec->intr = intr;
vec->jmp = JMP_INSN;
vec->offset = ( ( intptr_t ) interrupt_wrapper -
( intptr_t ) vec->next );
set_interrupt_vector ( intr, vec );
}
DBGC ( &intr_vec[0], "INTn vector at %p+%zxn (phys %#lx+%zxn)\n",
intr_vec, sizeof ( intr_vec[0] ),
virt_to_phys ( intr_vec ), sizeof ( intr_vec[0] ) );
/* Initialise the 32-bit interrupt descriptor table register */
idtr32.base = virt_to_phys ( idt32 );
/* Initialise the 64-bit interrupt descriptor table register,
* if applicable.
*/
if ( sizeof ( physaddr_t ) > sizeof ( uint32_t ) )
idtr64.base = virt_to_phys ( idt64 );
}
/**
* 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__ (( 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 );
}
/**
* Map pages for I/O
*
* @v bus_addr Bus address
* @v len Length of region
* @ret io_addr I/O address
*/
static void * ioremap_pages ( unsigned long bus_addr, size_t len ) {
unsigned long start;
unsigned int count;
unsigned int stride;
unsigned int first;
unsigned int i;
size_t offset;
void *io_addr;
DBGC ( &io_pages, "IO mapping %08lx+%zx\n", bus_addr, len );
/* Sanity check */
if ( ! len )
return NULL;
/* Round down start address to a page boundary */
start = ( bus_addr & ~( IO_PAGE_SIZE - 1 ) );
offset = ( bus_addr - start );
assert ( offset < IO_PAGE_SIZE );
/* Calculate number of pages required */
count = ( ( offset + len + IO_PAGE_SIZE - 1 ) / IO_PAGE_SIZE );
assert ( count != 0 );
assert ( count < ( sizeof ( io_pages.page ) /
sizeof ( io_pages.page[0] ) ) );
/* Round up number of pages to a power of two */
stride = ( 1 << ( fls ( count ) - 1 ) );
assert ( count <= stride );
/* Allocate pages */
for ( first = 0 ; first < ( sizeof ( io_pages.page ) /
sizeof ( io_pages.page[0] ) ) ;
first += stride ) {
/* Calculate I/O address */
io_addr = ( IO_BASE + ( first * IO_PAGE_SIZE ) + offset );
/* Check that page table entries are available */
for ( i = first ; i < ( first + count ) ; i++ ) {
if ( io_pages.page[i] & PAGE_P ) {
io_addr = NULL;
break;
}
}
if ( ! io_addr )
continue;
/* Create page table entries */
for ( i = first ; i < ( first + count ) ; i++ ) {
io_pages.page[i] = ( start | PAGE_P | PAGE_RW |
PAGE_US | PAGE_PWT | PAGE_PCD |
PAGE_PS );
start += IO_PAGE_SIZE;
}
/* Mark last page as being the last in this allocation */
io_pages.page[ i - 1 ] |= PAGE_LAST;
/* Return I/O address */
DBGC ( &io_pages, "IO mapped %08lx+%zx to %p using PTEs "
"[%d-%d]\n", bus_addr, len, io_addr, first,
( first + count - 1 ) );
return io_addr;
}
DBGC ( &io_pages, "IO could not map %08lx+%zx\n", bus_addr, len );
return NULL;
}
/**
* Unmap pages for I/O
*
* @v io_addr I/O address
*/
static void iounmap_pages ( volatile const void *io_addr ) {
volatile const void *invalidate = io_addr;
unsigned int first;
unsigned int i;
int is_last;
DBGC ( &io_pages, "IO unmapping %p\n", io_addr );
/* Calculate first page table entry */
first = ( ( io_addr - IO_BASE ) / IO_PAGE_SIZE );
/* Clear page table entries */
for ( i = first ; ; i++ ) {
/* Sanity check */
assert ( io_pages.page[i] & PAGE_P );
/* Check if this is the last page in this allocation */
is_last = ( io_pages.page[i] & PAGE_LAST );
/* Clear page table entry */
io_pages.page[i] = 0;
/* Invalidate TLB for this page */
__asm__ __volatile__ ( "invlpg (%0)" : : "r" ( invalidate ) );
invalidate += IO_PAGE_SIZE;
/* Terminate if this was the last page */
if ( is_last )
break;
}
DBGC ( &io_pages, "IO unmapped %p using PTEs [%d-%d]\n",
io_addr, first, i );
}
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 );
PROVIDE_IOMAP_INLINE ( pages, io_to_bus );
PROVIDE_IOMAP ( pages, ioremap, ioremap_pages );
PROVIDE_IOMAP ( pages, iounmap, iounmap_pages );
