/*++ @file
 POSIX Pthreads to emulate APs and implement threads

Copyright (c) 2011, Apple Inc. All rights reserved.
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.


**/

#include "SecMain.h"
#include <pthread.h>


UINTN
EFIAPI
PthreadMutexLock (
  IN VOID *Mutex
  )
{
  return (UINTN)pthread_mutex_lock ((pthread_mutex_t *)Mutex);
}



UINTN
EFIAPI
PthreadMutexUnLock (
  IN VOID *Mutex
  )                        
{
  return (UINTN)pthread_mutex_unlock ((pthread_mutex_t *)Mutex);
}

 
UINTN
EFIAPI
PthreadMutexTryLock (
  IN VOID *Mutex
  )                      
{
  return (UINTN)pthread_mutex_trylock ((pthread_mutex_t *)Mutex);
}


VOID *
PthreadMutexInit (
  IN VOID
  )
{
  pthread_mutex_t *Mutex;
  int             err;
  
  Mutex = malloc (sizeof (pthread_mutex_t));
  err = pthread_mutex_init (Mutex, NULL);
  if (err == 0) {
    return Mutex;
  }
  
  return NULL;
}


UINTN
PthreadMutexDestroy (
  IN VOID *Mutex
  )
{
  if (Mutex != NULL) {
    return pthread_mutex_destroy ((pthread_mutex_t *)Mutex);
  }
  
  return -1;
}

// Can't store this data on PthreadCreate stack so we need a global
typedef struct {
  pthread_mutex_t             Mutex;
  PTREAD_THUNK_THEAD_ENTRY    Start;
} THREAD_MANGLE;

THREAD_MANGLE mThreadMangle = {
  PTHREAD_MUTEX_INITIALIZER,
  NULL
};

VOID *
SecFakePthreadStart (
  VOID  *Context
  )
{
  PTREAD_THUNK_THEAD_ENTRY  Start;
  sigset_t                  SigMask;
  
  // Save global on the stack before we unlock
  Start   = mThreadMangle.Start;
  pthread_mutex_unlock (&mThreadMangle.Mutex);
  
  // Mask all signals to the APs
  sigfillset (&SigMask); 
  pthread_sigmask (SIG_BLOCK, &SigMask, NULL);
  
  //
  // We have to start the thread in SEC as we need to follow
  // OS X calling conventions. We can then call back into 
  // to the callers Start.
  //
  // This is a great example of how all problems in computer 
  // science can be solved by adding another level of indirection
  //
 return  (VOID *)ReverseGasketUint64 ((CALL_BACK)Start, (UINTN)Context);
}
  
UINTN
PthreadCreate (
  IN  VOID                      *Thread,
  IN  VOID                      *Attribute,
  IN  PTREAD_THUNK_THEAD_ENTRY  Start,
  IN  VOID                      *Context
  )
{
  int         err;
  BOOLEAN     EnabledOnEntry;    
  
  //
  // Threads inherit interrupt state so disable interrupts before we start thread
  //
  if (SecInterruptEanbled ()) {
    SecDisableInterrupt ();
    EnabledOnEntry = TRUE;
  } else {
    EnabledOnEntry = FALSE;
  }
  
  // Aquire lock for global, SecFakePthreadStart runs in a different thread.
  pthread_mutex_lock (&mThreadMangle.Mutex);
  mThreadMangle.Start   = Start;
  
  err = pthread_create (Thread, Attribute, SecFakePthreadStart, Context);
  if (err != 0) {
    // Thread failed to launch so release the lock;
    pthread_mutex_unlock (&mThreadMangle.Mutex);
  }
  
  if (EnabledOnEntry) {
    // Restore interrupt state
    SecEnableInterrupt ();
  }    

  return err;
}


VOID
PthreadExit (
  IN VOID *ValuePtr
  )
{ 
  pthread_exit (ValuePtr);
  return;
}

   
UINTN
PthreadSelf (
  VOID
  )
{
  // POSIX currently allows pthread_t to be a structure or arithmetic type.
  // Check out sys/types.h to make sure this will work if you are porting. 
  // On OS X (Darwin) pthread_t is a pointer to a structure so this code works.
  return (UINTN)pthread_self (); 
}


EMU_PTREAD_THUNK_PROTOCOL gPthreadThunk = {
  GasketPthreadMutexLock,
  GasketPthreadMutexUnLock,
  GasketPthreadMutexTryLock,
  GasketPthreadMutexInit,
  GasketPthreadMutexDestroy,
  GasketPthreadCreate,
  GasketPthreadExit,
  GasketPthreadSelf
};


EFI_STATUS
PthreadOpen (
  IN  EMU_IO_THUNK_PROTOCOL   *This
  )
{
  if (This->Instance != 0) {
    // Only single instance is supported
    return EFI_NOT_FOUND;
  }
  
  if (This->ConfigString[0] == L'0') {
    // If AP count is zero no need for threads
    return EFI_NOT_FOUND;
  }
  
  This->Interface = &gPthreadThunk;
  
  return EFI_SUCCESS;
}


EFI_STATUS
PthreadClose (
  IN  EMU_IO_THUNK_PROTOCOL   *This
  )
{
  return EFI_SUCCESS;
}


EMU_IO_THUNK_PROTOCOL gPthreadThunkIo = {
  &gEmuPthreadThunkProtocolGuid,
  NULL,
  NULL,
  0,
  GasketPthreadOpen,
  GasketPthreadClose,
  NULL
};