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[comboot] Use built-in interrupt reflector

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We now have the ability to handle interrupts while in protected mode,
and so no longer need to set up a dedicated interrupt descriptor table
while running COM32 executables.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown
2014-04-28 21:11:04 +01:00
parent 23b671daf4
commit aaf276ccd4
4 changed files with 5 additions and 133 deletions
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50
src/arch/i386/image/com32.c
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@@ -41,13 +41,6 @@ FILE_LICENCE ( GPL2_OR_LATER );
#include <ipxe/init.h>
#include <ipxe/io.h>
struct idt_register com32_external_idtr = {
.limit = COM32_NUM_IDT_ENTRIES * sizeof ( struct idt_descriptor ) - 1,
.base = COM32_IDT
};
struct idt_register com32_internal_idtr;
/**
* Execute COMBOOT image
*
@@ -95,8 +88,6 @@ static int com32_exec_loop ( struct image *image ) {
unregister_image ( image );
__asm__ __volatile__ (
"sidt com32_internal_idtr\n\t"
"lidt com32_external_idtr\n\t" /* Set up IDT */
"movl %%esp, (com32_internal_esp)\n\t" /* Save internal virtual address space ESP */
"movl (com32_external_esp), %%esp\n\t" /* Switch to COM32 ESP (top of available memory) */
"call _virt_to_phys\n\t" /* Switch to flat physical address space */
@@ -110,8 +101,7 @@ static int com32_exec_loop ( struct image *image ) {
"pushl $6\n\t" /* Number of additional arguments */
"call *%6\n\t" /* Execute image */
"cli\n\t" /* Disable interrupts */
"call _phys_to_virt\n\t" /* Switch back to internal virtual address space */
"lidt com32_internal_idtr\n\t" /* Switch back to internal IDT (for debugging) */
"call _phys_to_virt\n\t" /* Switch back to internal virtual address space */
"movl (com32_internal_esp), %%esp\n\t" /* Switch back to internal stack */
:
:
@@ -201,55 +191,25 @@ static int com32_identify ( struct image *image ) {
/**
* Load COM32 image into memory and set up the IDT
* Load COM32 image into memory
* @v image COM32 image
* @ret rc Return status code
*/
static int com32_load_image ( struct image *image ) {
physaddr_t com32_irq_wrapper_phys;
struct idt_descriptor *idt;
struct ijb_entry *ijb;
size_t filesz, memsz;
userptr_t buffer;
int rc, i;
int rc;
/* The interrupt descriptor table, interrupt jump buffer, and
* image data are all contiguous in memory. Prepare them all at once.
*/
filesz = image->len +
COM32_NUM_IDT_ENTRIES * sizeof ( struct idt_descriptor ) +
COM32_NUM_IDT_ENTRIES * sizeof ( struct ijb_entry );
filesz = image->len;
memsz = filesz;
buffer = phys_to_user ( COM32_IDT );
buffer = phys_to_user ( COM32_START_PHYS );
if ( ( rc = prep_segment ( buffer, filesz, memsz ) ) != 0 ) {
DBGC ( image, "COM32 %p: could not prepare segment: %s\n",
image, strerror ( rc ) );
return rc;
}
/* Write the IDT and IJB */
idt = phys_to_virt ( COM32_IDT );
ijb = phys_to_virt ( COM32_IJB );
com32_irq_wrapper_phys = virt_to_phys ( com32_irq_wrapper );
for ( i = 0; i < COM32_NUM_IDT_ENTRIES; i++ ) {
uint32_t ijb_address = virt_to_phys ( &ijb[i] );
idt[i].offset_low = ijb_address & 0xFFFF;
idt[i].selector = PHYSICAL_CS;
idt[i].flags = IDT_INTERRUPT_GATE_FLAGS;
idt[i].offset_high = ijb_address >> 16;
ijb[i].pusha_instruction = IJB_PUSHA;
ijb[i].mov_instruction = IJB_MOV_AL_IMM8;
ijb[i].mov_value = i;
ijb[i].jump_instruction = IJB_JMP_REL32;
ijb[i].jump_destination = com32_irq_wrapper_phys -
virt_to_phys ( &ijb[i + 1] );
}
/* Copy image to segment */
buffer = phys_to_user ( COM32_START_PHYS );
memcpy_user ( buffer, 0, image->data, 0, filesz );
return 0;