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[efi] Use a timer event to generate the currticks() timer 

We currently use the EFI_CPU_ARCH_PROTOCOL's GetTimerValue() method to
generate the currticks() timer, calibrated against a 1ms delay from
the boot services Stall() method.

This does not work on ARM platforms, where GetTimerValue() is an empty
stub which just returns EFI_UNSUPPORTED.

Fix by instead creating a periodic timer event, and using this event
to increment a current tick counter.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Michael Brown 2016-05-04 13:04:33 +01:00
parent 1e066431a4
commit 757ab98381
3 changed files with 88 additions and 354 deletions
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302
src/include/ipxe/efi/Protocol/Cpu.h
View File

@ -1,302 +0,0 @@
/** @file
CPU Architectural Protocol as defined in PI spec Volume 2 DXE
This code abstracts the DXE core from processor implementation details.
Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#ifndef __ARCH_PROTOCOL_CPU_H__
#define __ARCH_PROTOCOL_CPU_H__
FILE_LICENCE ( BSD3 );
#include <ipxe/efi/Protocol/DebugSupport.h>
#define EFI_CPU_ARCH_PROTOCOL_GUID \
{ 0x26baccb1, 0x6f42, 0x11d4, {0xbc, 0xe7, 0x0, 0x80, 0xc7, 0x3c, 0x88, 0x81 } }
typedef struct _EFI_CPU_ARCH_PROTOCOL EFI_CPU_ARCH_PROTOCOL;
///
/// The type of flush operation
///
typedef enum {
EfiCpuFlushTypeWriteBackInvalidate,
EfiCpuFlushTypeWriteBack,
EfiCpuFlushTypeInvalidate,
EfiCpuMaxFlushType
} EFI_CPU_FLUSH_TYPE;
///
/// The type of processor INIT.
///
typedef enum {
EfiCpuInit,
EfiCpuMaxInitType
} EFI_CPU_INIT_TYPE;
/**
EFI_CPU_INTERRUPT_HANDLER that is called when a processor interrupt occurs.
@param InterruptType Defines the type of interrupt or exception that
occurred on the processor.This parameter is processor architecture specific.
@param SystemContext A pointer to the processor context when
the interrupt occurred on the processor.
@return None
**/
typedef
VOID
(EFIAPI *EFI_CPU_INTERRUPT_HANDLER)(
IN CONST EFI_EXCEPTION_TYPE InterruptType,
IN CONST EFI_SYSTEM_CONTEXT SystemContext
);
/**
This function flushes the range of addresses from Start to Start+Length
from the processor's data cache. If Start is not aligned to a cache line
boundary, then the bytes before Start to the preceding cache line boundary
are also flushed. If Start+Length is not aligned to a cache line boundary,
then the bytes past Start+Length to the end of the next cache line boundary
are also flushed. The FlushType of EfiCpuFlushTypeWriteBackInvalidate must be
supported. If the data cache is fully coherent with all DMA operations, then
this function can just return EFI_SUCCESS. If the processor does not support
flushing a range of the data cache, then the entire data cache can be flushed.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param Start The beginning physical address to flush from the processor's data
cache.
@param Length The number of bytes to flush from the processor's data cache. This
function may flush more bytes than Length specifies depending upon
the granularity of the flush operation that the processor supports.
@param FlushType Specifies the type of flush operation to perform.
@retval EFI_SUCCESS The address range from Start to Start+Length was flushed from
the processor's data cache.
@retval EFI_UNSUPPORTEDT The processor does not support the cache flush type specified
by FlushType.
@retval EFI_DEVICE_ERROR The address range from Start to Start+Length could not be flushed
from the processor's data cache.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_FLUSH_DATA_CACHE)(
IN EFI_CPU_ARCH_PROTOCOL *This,
IN EFI_PHYSICAL_ADDRESS Start,
IN UINT64 Length,
IN EFI_CPU_FLUSH_TYPE FlushType
);
/**
This function enables interrupt processing by the processor.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@retval EFI_SUCCESS Interrupts are enabled on the processor.
@retval EFI_DEVICE_ERROR Interrupts could not be enabled on the processor.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_ENABLE_INTERRUPT)(
IN EFI_CPU_ARCH_PROTOCOL *This
);
/**
This function disables interrupt processing by the processor.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@retval EFI_SUCCESS Interrupts are disabled on the processor.
@retval EFI_DEVICE_ERROR Interrupts could not be disabled on the processor.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_DISABLE_INTERRUPT)(
IN EFI_CPU_ARCH_PROTOCOL *This
);
/**
This function retrieves the processor's current interrupt state a returns it in
State. If interrupts are currently enabled, then TRUE is returned. If interrupts
are currently disabled, then FALSE is returned.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param State A pointer to the processor's current interrupt state. Set to TRUE if
interrupts are enabled and FALSE if interrupts are disabled.
@retval EFI_SUCCESS The processor's current interrupt state was returned in State.
@retval EFI_INVALID_PARAMETER State is NULL.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_GET_INTERRUPT_STATE)(
IN EFI_CPU_ARCH_PROTOCOL *This,
OUT BOOLEAN *State
);
/**
This function generates an INIT on the processor. If this function succeeds, then the
processor will be reset, and control will not be returned to the caller. If InitType is
not supported by this processor, or the processor cannot programmatically generate an
INIT without help from external hardware, then EFI_UNSUPPORTED is returned. If an error
occurs attempting to generate an INIT, then EFI_DEVICE_ERROR is returned.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param InitType The type of processor INIT to perform.
@retval EFI_SUCCESS The processor INIT was performed. This return code should never be seen.
@retval EFI_UNSUPPORTED The processor INIT operation specified by InitType is not supported
by this processor.
@retval EFI_DEVICE_ERROR The processor INIT failed.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_INIT)(
IN EFI_CPU_ARCH_PROTOCOL *This,
IN EFI_CPU_INIT_TYPE InitType
);
/**
This function registers and enables the handler specified by InterruptHandler for a processor
interrupt or exception type specified by InterruptType. If InterruptHandler is NULL, then the
handler for the processor interrupt or exception type specified by InterruptType is uninstalled.
The installed handler is called once for each processor interrupt or exception.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param InterruptType A pointer to the processor's current interrupt state. Set to TRUE if interrupts
are enabled and FALSE if interrupts are disabled.
@param InterruptHandler A pointer to a function of type EFI_CPU_INTERRUPT_HANDLER that is called
when a processor interrupt occurs. If this parameter is NULL, then the handler
will be uninstalled.
@retval EFI_SUCCESS The handler for the processor interrupt was successfully installed or uninstalled.
@retval EFI_ALREADY_STARTED InterruptHandler is not NULL, and a handler for InterruptType was
previously installed.
@retval EFI_INVALID_PARAMETER InterruptHandler is NULL, and a handler for InterruptType was not
previously installed.
@retval EFI_UNSUPPORTED The interrupt specified by InterruptType is not supported.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_REGISTER_INTERRUPT_HANDLER)(
IN EFI_CPU_ARCH_PROTOCOL *This,
IN EFI_EXCEPTION_TYPE InterruptType,
IN EFI_CPU_INTERRUPT_HANDLER InterruptHandler
);
/**
This function reads the processor timer specified by TimerIndex and returns it in TimerValue.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param TimerIndex Specifies which processor timer is to be returned in TimerValue. This parameter
must be between 0 and NumberOfTimers-1.
@param TimerValue Pointer to the returned timer value.
@param TimerPeriod A pointer to the amount of time that passes in femtoseconds for each increment
of TimerValue. If TimerValue does not increment at a predictable rate, then 0 is
returned. This parameter is optional and may be NULL.
@retval EFI_SUCCESS The processor timer value specified by TimerIndex was returned in TimerValue.
@retval EFI_DEVICE_ERROR An error occurred attempting to read one of the processor's timers.
@retval EFI_INVALID_PARAMETER TimerValue is NULL or TimerIndex is not valid.
@retval EFI_UNSUPPORTED The processor does not have any readable timers.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_GET_TIMER_VALUE)(
IN EFI_CPU_ARCH_PROTOCOL *This,
IN UINT32 TimerIndex,
OUT UINT64 *TimerValue,
OUT UINT64 *TimerPeriod OPTIONAL
);
/**
This function modifies the attributes for the memory region specified by BaseAddress and
Length from their current attributes to the attributes specified by Attributes.
@param This The EFI_CPU_ARCH_PROTOCOL instance.
@param BaseAddress The physical address that is the start address of a memory region.
@param Length The size in bytes of the memory region.
@param Attributes The bit mask of attributes to set for the memory region.
@retval EFI_SUCCESS The attributes were set for the memory region.
@retval EFI_ACCESS_DENIED The attributes for the memory resource range specified by
BaseAddress and Length cannot be modified.
@retval EFI_INVALID_PARAMETER Length is zero.
Attributes specified an illegal combination of attributes that
cannot be set together.
@retval EFI_OUT_OF_RESOURCES There are not enough system resources to modify the attributes of
the memory resource range.
@retval EFI_UNSUPPORTED The processor does not support one or more bytes of the memory
resource range specified by BaseAddress and Length.
The bit mask of attributes is not support for the memory resource
range specified by BaseAddress and Length.
**/
typedef
EFI_STATUS
(EFIAPI *EFI_CPU_SET_MEMORY_ATTRIBUTES)(
IN EFI_CPU_ARCH_PROTOCOL *This,
IN EFI_PHYSICAL_ADDRESS BaseAddress,
IN UINT64 Length,
IN UINT64 Attributes
);
///
/// The EFI_CPU_ARCH_PROTOCOL is used to abstract processor-specific functions from the DXE
/// Foundation. This includes flushing caches, enabling and disabling interrupts, hooking interrupt
/// vectors and exception vectors, reading internal processor timers, resetting the processor, and
/// determining the processor frequency.
///
struct _EFI_CPU_ARCH_PROTOCOL {
EFI_CPU_FLUSH_DATA_CACHE FlushDataCache;
EFI_CPU_ENABLE_INTERRUPT EnableInterrupt;
EFI_CPU_DISABLE_INTERRUPT DisableInterrupt;
EFI_CPU_GET_INTERRUPT_STATE GetInterruptState;
EFI_CPU_INIT Init;
EFI_CPU_REGISTER_INTERRUPT_HANDLER RegisterInterruptHandler;
EFI_CPU_GET_TIMER_VALUE GetTimerValue;
EFI_CPU_SET_MEMORY_ATTRIBUTES SetMemoryAttributes;
///
/// The number of timers that are available in a processor. The value in this
/// field is a constant that must not be modified after the CPU Architectural
/// Protocol is installed. All consumers must treat this as a read-only field.
///
UINT32 NumberOfTimers;
///
/// The size, in bytes, of the alignment required for DMA buffer allocations.
/// This is typically the size of the largest data cache line in the platform.
/// The value in this field is a constant that must not be modified after the
/// CPU Architectural Protocol is installed. All consumers must treat this as
/// a read-only field.
///
UINT32 DmaBufferAlignment;
};
extern EFI_GUID gEfiCpuArchProtocolGuid;
#endif

18
src/include/ipxe/efi/efi_timer.h
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@ -15,4 +15,22 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define TIMER_PREFIX_efi __efi_
#endif
/**
* Number of ticks per second
*
* This is a policy decision.
*/
#define EFI_TICKS_PER_SEC 20
/**
* Get number of ticks per second
*
* @ret ticks_per_sec Number of ticks per second
*/
static inline __attribute__ (( always_inline )) unsigned long
TIMER_INLINE ( efi, ticks_per_sec ) ( void ) {
return EFI_TICKS_PER_SEC;
}
#endif /* _IPXE_EFI_TIMER_H */

122
src/interface/efi/efi_timer.c
View File

@ -25,12 +25,10 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#include <string.h>
#include <errno.h>
#include <limits.h>
#include <assert.h>
#include <unistd.h>
#include <ipxe/timer.h>
#include <ipxe/init.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/Protocol/Cpu.h>
/** @file
*
@ -38,19 +36,14 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
*
*/
/** Scale factor to apply to CPU timer 0
*
* The timer is scaled down in order to ensure that reasonable values
* for "number of ticks" don't exceed the size of an unsigned long.
*/
#define EFI_TIMER0_SHIFT 12
/** Current tick count */
static unsigned long efi_jiffies;
/** Calibration time */
#define EFI_CALIBRATE_DELAY_MS 1
/** Timer tick event */
static EFI_EVENT efi_tick_event;
/** CPU protocol */
static EFI_CPU_ARCH_PROTOCOL *cpu_arch;
EFI_REQUIRE_PROTOCOL ( EFI_CPU_ARCH_PROTOCOL, &cpu_arch );
/** Colour for debug messages */
#define colour &efi_jiffies
/**
* Delay for a fixed number of microseconds
@ -64,8 +57,8 @@ static void efi_udelay ( unsigned long usecs ) {
if ( ( efirc = bs->Stall ( usecs ) ) != 0 ) {
rc = -EEFI ( efirc );
DBG ( "EFI could not delay for %ldus: %s\n",
usecs, strerror ( rc ) );
DBGC ( colour, "EFI could not delay for %ldus: %s\n",
usecs, strerror ( rc ) );
/* Probably screwed */
}
}
@ -76,53 +69,78 @@ static void efi_udelay ( unsigned long usecs ) {
* @ret ticks Current time, in ticks
*/
static unsigned long efi_currticks ( void ) {
UINT64 time;
EFI_STATUS efirc;
int rc;
/* Read CPU timer 0 (TSC) */
if ( ( efirc = cpu_arch->GetTimerValue ( cpu_arch, 0, &time,
NULL ) ) != 0 ) {
rc = -EEFI ( efirc );
DBG ( "EFI could not read CPU timer: %s\n", strerror ( rc ) );
/* Probably screwed */
return -1UL;
}
return ( time >> EFI_TIMER0_SHIFT );
return efi_jiffies;
}
/**
* Get number of ticks per second
* Timer tick
*
* @ret ticks_per_sec Number of ticks per second
* @v event Timer tick event
* @v context Event context
*/
static unsigned long efi_ticks_per_sec ( void ) {
static unsigned long ticks_per_sec = 0;
static EFIAPI void efi_tick ( EFI_EVENT event __unused,
void *context __unused ) {
/* Calibrate timer, if necessary. EFI does nominally provide
* the timer speed via the (optional) TimerPeriod parameter to
* the GetTimerValue() call, but it gets the speed slightly
* wrong. By up to three orders of magnitude. Not helpful.
*/
if ( ! ticks_per_sec ) {
unsigned long start;
unsigned long elapsed;
/* Increment tick count */
efi_jiffies++;
}
DBG ( "Calibrating EFI timer with a %d ms delay\n",
EFI_CALIBRATE_DELAY_MS );
start = currticks();
mdelay ( EFI_CALIBRATE_DELAY_MS );
elapsed = ( currticks() - start );
ticks_per_sec = ( elapsed * ( 1000 / EFI_CALIBRATE_DELAY_MS ));
DBG ( "EFI CPU timer calibrated at %ld ticks in %d ms (%ld "
"ticks/sec)\n", elapsed, EFI_CALIBRATE_DELAY_MS,
ticks_per_sec );
/**
* Start timer tick
*
*/
static void efi_tick_startup ( void ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
EFI_STATUS efirc;
int rc;
/* Create timer tick event */
if ( ( efirc = bs->CreateEvent ( ( EVT_TIMER | EVT_NOTIFY_SIGNAL ),
TPL_CALLBACK, efi_tick, NULL,
&efi_tick_event ) ) != 0 ) {
rc = -EEFI ( efirc );
DBGC ( colour, "EFI could not create timer tick: %s\n",
strerror ( rc ) );
/* Nothing we can do about it */
return;
}
return ticks_per_sec;
/* Start timer tick */
if ( ( efirc = bs->SetTimer ( efi_tick_event, TimerPeriodic,
( 10000000 / EFI_TICKS_PER_SEC ) ) ) !=0){
rc = -EEFI ( efirc );
DBGC ( colour, "EFI could not start timer tick: %s\n",
strerror ( rc ) );
/* Nothing we can do about it */
return;
}
DBGC ( colour, "EFI timer started at %d ticks per second\n",
EFI_TICKS_PER_SEC );
}
/**
* Stop timer tick
*
* @v booting System is shutting down in order to boot
*/
static void efi_tick_shutdown ( int booting __unused ) {
EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
/* Stop timer tick */
bs->SetTimer ( efi_tick_event, TimerCancel, 0 );
DBGC ( colour, "EFI timer stopped\n" );
/* Destroy timer tick event */
bs->CloseEvent ( efi_tick_event );
}
/** Timer tick startup function */
struct startup_fn efi_tick_startup_fn __startup_fn ( STARTUP_EARLY ) = {
.startup = efi_tick_startup,
.shutdown = efi_tick_shutdown,
};
PROVIDE_TIMER ( efi, udelay, efi_udelay );
PROVIDE_TIMER ( efi, currticks, efi_currticks );
PROVIDE_TIMER ( efi, ticks_per_sec, efi_ticks_per_sec );
PROVIDE_TIMER_INLINE ( efi, ticks_per_sec );