paulbergmann_mpstubs/boot/startup_ap.cc

84 lines
2.5 KiB
C++

#include "startup_ap.h"
#include "utils/string.h"
#include "utils/size.h"
#include "debug/output.h"
#include "debug/assert.h"
#include "machine/lapic.h"
#include "machine/core_interrupt.h"
#include "machine/gdt.h"
#include "machine/pit.h"
namespace ApplicationProcessor {
// Make sure that the RELOCATED_SETUP is in low memory (< 1 MiB)
static_assert((RELOCATED_SETUP & ~0x000ff000) == 0, "Not a valid 1 MB address for RELOCATED_SETUP!");
/*! \brief Temporary Global Descriptor Table
*
* Blue print, to be copied into real mode code
*/
constexpr GDT::SegmentDescriptor ap_gdt[] = {
// nullptr-Deskriptor
{},
// code segment
{ /* base = */ 0x0,
/* limit = */ 0xFFFFFFFF,
/* code = */ true,
/* ring = */ 0,
/* size = */ GDT::SIZE_32BIT },
// data segment
{ /* base = */ 0x0,
/* limit = */ 0xFFFFFFFF,
/* code = */ false,
/* ring = */ 0,
/* size = */ GDT::SIZE_32BIT },
};
void relocateSetupCode() {
// Relocated setup code
memcpy(reinterpret_cast<void*>(RELOCATED_SETUP), &___SETUP_AP_START__, &___SETUP_AP_END__ - &___SETUP_AP_START__);
// Adjust GDT:
// Calculate offset for real mode GDT and GDT descriptor
uintptr_t ap_gdt_offset = reinterpret_cast<uintptr_t>(&setup_ap_gdt) -
reinterpret_cast<uintptr_t>(&___SETUP_AP_START__);
uintptr_t ap_gdtd_offset = reinterpret_cast<uintptr_t>(&setup_ap_gdtd) -
reinterpret_cast<uintptr_t>(&___SETUP_AP_START__);
// Copy blue print of real mode GDT to the relocated memory
void * relocated_ap_gdt = reinterpret_cast<void*>(RELOCATED_SETUP + ap_gdt_offset);
memcpy(relocated_ap_gdt, &ap_gdt, sizeof(ap_gdt));
// Calculate GDT descriptor for relocated address
GDT::Pointer * relocated_ap_gdtd = reinterpret_cast<GDT::Pointer*>(RELOCATED_SETUP + ap_gdtd_offset);
relocated_ap_gdtd->set(relocated_ap_gdt, size(ap_gdt));
}
void boot(void) {
assert(!Core::Interrupt::isEnabled() && "Interrupts should not be enabled before APs have booted!");
// Relocate setup code
relocateSetupCode();
// Calculate Init-IPI vector based on address of relocated setup_ap()
uint8_t vector = RELOCATED_SETUP >> 12;
// Send Init-IPI to all APs
LAPIC::IPI::sendInit();
// wait at least 10ms
PIT::delay(10000);
// Send Startup-IPI twice
DBG_VERBOSE << "Sending STARTUP IPI #1" << endl;
LAPIC::IPI::sendStartup(vector);
// wait at least 200us
PIT::delay(200);
DBG_VERBOSE << "Sending STARTUP IPI #2" << endl;
LAPIC::IPI::sendStartup(vector);
}
} // namespace ApplicationProcessor