239b50a863
RestoreTPL called while at TPL_HIGH_LEVEL unconditionally enables interrupts even if called in interrupt handler. That opens a window while interrupt is not completely handled but another interrupt could be accepted. If a VM starts on a heavily loaded host hundreds of periodic timer interrupts might be queued while vCPU is descheduled (the behavior is typical for a Xen host). The next time vCPU is scheduled again all of them get delivered back to back causing OVMF to accept each one without finishing a previous one and cleaning up the stack. That quickly results in stack overflow and a triple fault. Fix it by postponing sending EOI until we finished processing the current tick giving interrupt handler opportunity to clean up the stack before accepting the next tick. Signed-off-by: Igor Druzhinin <igor.druzhinin@citrix.com> Message-Id: <1592275782-9369-1-git-send-email-igor.druzhinin@citrix.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=2815 Acked-by: Laszlo Ersek <lersek@redhat.com> [lersek@redhat.com: add BZ ref; rewrap msg to silence PatchCheck.py]
403 lines
12 KiB
C
403 lines
12 KiB
C
/** @file
|
|
Timer Architectural Protocol as defined in the DXE CIS
|
|
|
|
Copyright (c) 2005 - 2018, Intel Corporation. All rights reserved.<BR>
|
|
SPDX-License-Identifier: BSD-2-Clause-Patent
|
|
|
|
**/
|
|
|
|
#include "Timer.h"
|
|
|
|
//
|
|
// The handle onto which the Timer Architectural Protocol will be installed
|
|
//
|
|
EFI_HANDLE mTimerHandle = NULL;
|
|
|
|
//
|
|
// The Timer Architectural Protocol that this driver produces
|
|
//
|
|
EFI_TIMER_ARCH_PROTOCOL mTimer = {
|
|
TimerDriverRegisterHandler,
|
|
TimerDriverSetTimerPeriod,
|
|
TimerDriverGetTimerPeriod,
|
|
TimerDriverGenerateSoftInterrupt
|
|
};
|
|
|
|
//
|
|
// Pointer to the CPU Architectural Protocol instance
|
|
//
|
|
EFI_CPU_ARCH_PROTOCOL *mCpu;
|
|
|
|
//
|
|
// Pointer to the Legacy 8259 Protocol instance
|
|
//
|
|
EFI_LEGACY_8259_PROTOCOL *mLegacy8259;
|
|
|
|
//
|
|
// The notification function to call on every timer interrupt.
|
|
// A bug in the compiler prevents us from initializing this here.
|
|
//
|
|
EFI_TIMER_NOTIFY mTimerNotifyFunction;
|
|
|
|
//
|
|
// The current period of the timer interrupt
|
|
//
|
|
volatile UINT64 mTimerPeriod = 0;
|
|
|
|
//
|
|
// Worker Functions
|
|
//
|
|
/**
|
|
Sets the counter value for Timer #0 in a legacy 8254 timer.
|
|
|
|
@param Count The 16-bit counter value to program into Timer #0 of the legacy 8254 timer.
|
|
**/
|
|
VOID
|
|
SetPitCount (
|
|
IN UINT16 Count
|
|
)
|
|
{
|
|
IoWrite8 (TIMER_CONTROL_PORT, 0x36);
|
|
IoWrite8 (TIMER0_COUNT_PORT, (UINT8)(Count & 0xff));
|
|
IoWrite8 (TIMER0_COUNT_PORT, (UINT8)((Count >> 8) & 0xff));
|
|
}
|
|
|
|
/**
|
|
8254 Timer #0 Interrupt Handler.
|
|
|
|
@param InterruptType The type of interrupt that occurred
|
|
@param SystemContext A pointer to the system context when the interrupt occurred
|
|
**/
|
|
VOID
|
|
EFIAPI
|
|
TimerInterruptHandler (
|
|
IN EFI_EXCEPTION_TYPE InterruptType,
|
|
IN EFI_SYSTEM_CONTEXT SystemContext
|
|
)
|
|
{
|
|
EFI_TPL OriginalTPL;
|
|
|
|
OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
|
|
|
|
if (mTimerNotifyFunction != NULL) {
|
|
//
|
|
// @bug : This does not handle missed timer interrupts
|
|
//
|
|
mTimerNotifyFunction (mTimerPeriod);
|
|
}
|
|
|
|
gBS->RestoreTPL (OriginalTPL);
|
|
|
|
DisableInterrupts ();
|
|
mLegacy8259->EndOfInterrupt (mLegacy8259, Efi8259Irq0);
|
|
}
|
|
|
|
/**
|
|
|
|
This function registers the handler NotifyFunction so it is called every time
|
|
the timer interrupt fires. It also passes the amount of time since the last
|
|
handler call to the NotifyFunction. If NotifyFunction is NULL, then the
|
|
handler is unregistered. If the handler is registered, then EFI_SUCCESS is
|
|
returned. If the CPU does not support registering a timer interrupt handler,
|
|
then EFI_UNSUPPORTED is returned. If an attempt is made to register a handler
|
|
when a handler is already registered, then EFI_ALREADY_STARTED is returned.
|
|
If an attempt is made to unregister a handler when a handler is not registered,
|
|
then EFI_INVALID_PARAMETER is returned. If an error occurs attempting to
|
|
register the NotifyFunction with the timer interrupt, then EFI_DEVICE_ERROR
|
|
is returned.
|
|
|
|
|
|
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
|
|
@param NotifyFunction The function to call when a timer interrupt fires. This
|
|
function executes at TPL_HIGH_LEVEL. The DXE Core will
|
|
register a handler for the timer interrupt, so it can know
|
|
how much time has passed. This information is used to
|
|
signal timer based events. NULL will unregister the handler.
|
|
|
|
@retval EFI_SUCCESS The timer handler was registered.
|
|
@retval EFI_UNSUPPORTED The platform does not support timer interrupts.
|
|
@retval EFI_ALREADY_STARTED NotifyFunction is not NULL, and a handler is already
|
|
registered.
|
|
@retval EFI_INVALID_PARAMETER NotifyFunction is NULL, and a handler was not
|
|
previously registered.
|
|
@retval EFI_DEVICE_ERROR The timer handler could not be registered.
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
TimerDriverRegisterHandler (
|
|
IN EFI_TIMER_ARCH_PROTOCOL *This,
|
|
IN EFI_TIMER_NOTIFY NotifyFunction
|
|
)
|
|
{
|
|
//
|
|
// Check for invalid parameters
|
|
//
|
|
if (NotifyFunction == NULL && mTimerNotifyFunction == NULL) {
|
|
return EFI_INVALID_PARAMETER;
|
|
}
|
|
|
|
if (NotifyFunction != NULL && mTimerNotifyFunction != NULL) {
|
|
return EFI_ALREADY_STARTED;
|
|
}
|
|
|
|
mTimerNotifyFunction = NotifyFunction;
|
|
|
|
return EFI_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
|
|
This function adjusts the period of timer interrupts to the value specified
|
|
by TimerPeriod. If the timer period is updated, then the selected timer
|
|
period is stored in EFI_TIMER.TimerPeriod, and EFI_SUCCESS is returned. If
|
|
the timer hardware is not programmable, then EFI_UNSUPPORTED is returned.
|
|
If an error occurs while attempting to update the timer period, then the
|
|
timer hardware will be put back in its state prior to this call, and
|
|
EFI_DEVICE_ERROR is returned. If TimerPeriod is 0, then the timer interrupt
|
|
is disabled. This is not the same as disabling the CPU's interrupts.
|
|
Instead, it must either turn off the timer hardware, or it must adjust the
|
|
interrupt controller so that a CPU interrupt is not generated when the timer
|
|
interrupt fires.
|
|
|
|
|
|
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
|
|
@param TimerPeriod The rate to program the timer interrupt in 100 nS units. If
|
|
the timer hardware is not programmable, then EFI_UNSUPPORTED is
|
|
returned. If the timer is programmable, then the timer period
|
|
will be rounded up to the nearest timer period that is supported
|
|
by the timer hardware. If TimerPeriod is set to 0, then the
|
|
timer interrupts will be disabled.
|
|
|
|
@retval EFI_SUCCESS The timer period was changed.
|
|
@retval EFI_UNSUPPORTED The platform cannot change the period of the timer interrupt.
|
|
@retval EFI_DEVICE_ERROR The timer period could not be changed due to a device error.
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
TimerDriverSetTimerPeriod (
|
|
IN EFI_TIMER_ARCH_PROTOCOL *This,
|
|
IN UINT64 TimerPeriod
|
|
)
|
|
{
|
|
UINT64 TimerCount;
|
|
|
|
//
|
|
// The basic clock is 1.19318 MHz or 0.119318 ticks per 100 ns.
|
|
// TimerPeriod * 0.119318 = 8254 timer divisor. Using integer arithmetic
|
|
// TimerCount = (TimerPeriod * 119318)/1000000.
|
|
//
|
|
// Round up to next highest integer. This guarantees that the timer is
|
|
// equal to or slightly longer than the requested time.
|
|
// TimerCount = ((TimerPeriod * 119318) + 500000)/1000000
|
|
//
|
|
// Note that a TimerCount of 0 is equivalent to a count of 65,536
|
|
//
|
|
// Since TimerCount is limited to 16 bits for IA32, TimerPeriod is limited
|
|
// to 20 bits.
|
|
//
|
|
if (TimerPeriod == 0) {
|
|
//
|
|
// Disable timer interrupt for a TimerPeriod of 0
|
|
//
|
|
mLegacy8259->DisableIrq (mLegacy8259, Efi8259Irq0);
|
|
} else {
|
|
|
|
//
|
|
// Convert TimerPeriod into 8254 counts
|
|
//
|
|
TimerCount = DivU64x32 (MultU64x32 (119318, (UINT32) TimerPeriod) + 500000, 1000000);
|
|
|
|
//
|
|
// Check for overflow
|
|
//
|
|
if (TimerCount >= 65536) {
|
|
TimerCount = 0;
|
|
TimerPeriod = MAX_TIMER_TICK_DURATION;
|
|
}
|
|
//
|
|
// Program the 8254 timer with the new count value
|
|
//
|
|
SetPitCount ((UINT16) TimerCount);
|
|
|
|
//
|
|
// Enable timer interrupt
|
|
//
|
|
mLegacy8259->EnableIrq (mLegacy8259, Efi8259Irq0, FALSE);
|
|
}
|
|
//
|
|
// Save the new timer period
|
|
//
|
|
mTimerPeriod = TimerPeriod;
|
|
|
|
return EFI_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
|
|
This function retrieves the period of timer interrupts in 100 ns units,
|
|
returns that value in TimerPeriod, and returns EFI_SUCCESS. If TimerPeriod
|
|
is NULL, then EFI_INVALID_PARAMETER is returned. If a TimerPeriod of 0 is
|
|
returned, then the timer is currently disabled.
|
|
|
|
|
|
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
|
|
@param TimerPeriod A pointer to the timer period to retrieve in 100 ns units. If
|
|
0 is returned, then the timer is currently disabled.
|
|
|
|
@retval EFI_SUCCESS The timer period was returned in TimerPeriod.
|
|
@retval EFI_INVALID_PARAMETER TimerPeriod is NULL.
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
TimerDriverGetTimerPeriod (
|
|
IN EFI_TIMER_ARCH_PROTOCOL *This,
|
|
OUT UINT64 *TimerPeriod
|
|
)
|
|
{
|
|
if (TimerPeriod == NULL) {
|
|
return EFI_INVALID_PARAMETER;
|
|
}
|
|
|
|
*TimerPeriod = mTimerPeriod;
|
|
|
|
return EFI_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
|
|
This function generates a soft timer interrupt. If the platform does not support soft
|
|
timer interrupts, then EFI_UNSUPPORTED is returned. Otherwise, EFI_SUCCESS is returned.
|
|
If a handler has been registered through the EFI_TIMER_ARCH_PROTOCOL.RegisterHandler()
|
|
service, then a soft timer interrupt will be generated. If the timer interrupt is
|
|
enabled when this service is called, then the registered handler will be invoked. The
|
|
registered handler should not be able to distinguish a hardware-generated timer
|
|
interrupt from a software-generated timer interrupt.
|
|
|
|
|
|
@param This The EFI_TIMER_ARCH_PROTOCOL instance.
|
|
|
|
@retval EFI_SUCCESS The soft timer interrupt was generated.
|
|
@retval EFI_UNSUPPORTED The platform does not support the generation of soft timer interrupts.
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
TimerDriverGenerateSoftInterrupt (
|
|
IN EFI_TIMER_ARCH_PROTOCOL *This
|
|
)
|
|
{
|
|
EFI_STATUS Status;
|
|
UINT16 IRQMask;
|
|
EFI_TPL OriginalTPL;
|
|
|
|
//
|
|
// If the timer interrupt is enabled, then the registered handler will be invoked.
|
|
//
|
|
Status = mLegacy8259->GetMask (mLegacy8259, NULL, NULL, &IRQMask, NULL);
|
|
ASSERT_EFI_ERROR (Status);
|
|
if ((IRQMask & 0x1) == 0) {
|
|
//
|
|
// Invoke the registered handler
|
|
//
|
|
OriginalTPL = gBS->RaiseTPL (TPL_HIGH_LEVEL);
|
|
|
|
if (mTimerNotifyFunction != NULL) {
|
|
//
|
|
// @bug : This does not handle missed timer interrupts
|
|
//
|
|
mTimerNotifyFunction (mTimerPeriod);
|
|
}
|
|
|
|
gBS->RestoreTPL (OriginalTPL);
|
|
} else {
|
|
return EFI_UNSUPPORTED;
|
|
}
|
|
|
|
return EFI_SUCCESS;
|
|
}
|
|
|
|
/**
|
|
Initialize the Timer Architectural Protocol driver
|
|
|
|
@param ImageHandle ImageHandle of the loaded driver
|
|
@param SystemTable Pointer to the System Table
|
|
|
|
@retval EFI_SUCCESS Timer Architectural Protocol created
|
|
@retval EFI_OUT_OF_RESOURCES Not enough resources available to initialize driver.
|
|
@retval EFI_DEVICE_ERROR A device error occurred attempting to initialize the driver.
|
|
|
|
**/
|
|
EFI_STATUS
|
|
EFIAPI
|
|
TimerDriverInitialize (
|
|
IN EFI_HANDLE ImageHandle,
|
|
IN EFI_SYSTEM_TABLE *SystemTable
|
|
)
|
|
{
|
|
EFI_STATUS Status;
|
|
UINT32 TimerVector;
|
|
|
|
//
|
|
// Initialize the pointer to our notify function.
|
|
//
|
|
mTimerNotifyFunction = NULL;
|
|
|
|
//
|
|
// Make sure the Timer Architectural Protocol is not already installed in the system
|
|
//
|
|
ASSERT_PROTOCOL_ALREADY_INSTALLED (NULL, &gEfiTimerArchProtocolGuid);
|
|
|
|
//
|
|
// Find the CPU architectural protocol.
|
|
//
|
|
Status = gBS->LocateProtocol (&gEfiCpuArchProtocolGuid, NULL, (VOID **) &mCpu);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Find the Legacy8259 protocol.
|
|
//
|
|
Status = gBS->LocateProtocol (&gEfiLegacy8259ProtocolGuid, NULL, (VOID **) &mLegacy8259);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Force the timer to be disabled
|
|
//
|
|
Status = TimerDriverSetTimerPeriod (&mTimer, 0);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Get the interrupt vector number corresponding to IRQ0 from the 8259 driver
|
|
//
|
|
TimerVector = 0;
|
|
Status = mLegacy8259->GetVector (mLegacy8259, Efi8259Irq0, (UINT8 *) &TimerVector);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Install interrupt handler for 8254 Timer #0 (ISA IRQ0)
|
|
//
|
|
Status = mCpu->RegisterInterruptHandler (mCpu, TimerVector, TimerInterruptHandler);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Force the timer to be enabled at its default period
|
|
//
|
|
Status = TimerDriverSetTimerPeriod (&mTimer, DEFAULT_TIMER_TICK_DURATION);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
//
|
|
// Install the Timer Architectural Protocol onto a new handle
|
|
//
|
|
Status = gBS->InstallMultipleProtocolInterfaces (
|
|
&mTimerHandle,
|
|
&gEfiTimerArchProtocolGuid, &mTimer,
|
|
NULL
|
|
);
|
|
ASSERT_EFI_ERROR (Status);
|
|
|
|
return Status;
|
|
}
|
|
|