/* 
   Device File Virtualization Guest Preload Library Helpers

   (c) Akhil Guliani and William Gross, 2015
     
   Adapted from MPI module (c) 2012 Peter Dinda

   Note that the calling convention here is a bit different
   since we need to return errno 


*/

#ifndef __HCALL__
#define __HCALL__

/*
  Calling convention:

64 bit:
  rax = hcall number
  rbx = 0x6464646464646464...
  rcx = 1st arg
  rdx = 2nd arg
  rsi = 3rd arg
  rdi = 4th arg
  r8  = 5th arg
  r9  = 6th arg
  r10 = 7th arg
  r11 = 8th arg

32 bit:
  eax = hcall number
  ebx = 0x32323232
  arguments on stack in C order (first argument is TOS)
     arguments are also 32 bit

In this convention, 
  RAX is assumed to be the return code from the system call
  RBX is assumed to be the errno set by the system call

  RAX comes back via rc
  RBX comes back via overwrite of id
*/
#define HCALL64(rc,id,a,b,c,d,e,f,g,h)		      \
  asm volatile ("movq %1, %%rax; "		      \
		"pushq %%rbx; "			      \
		"movq $0x6464646464646464, %%rbx; "   \
		"movq %2, %%rcx; "		      \
		"movq %3, %%rdx; "		      \
		"movq %4, %%rsi; "		      \
		"movq %5, %%rdi; "		      \
		"movq %6, %%r8 ; "		      \
		"movq %7, %%r9 ; "		      \
		"movq %8, %%r10; "		      \
		"movq %9, %%r11; "		      \
		"vmmcall ;       "		      \
		"movq %%rax, %0; "		      \
		"movq %%rbx, %1; "		      \
		"popq %%rbx; "			      \
		: "=m"(rc),"=m"(id)		      \
		: "m"(a), "m"(b), "m"(c), "m"(d),      \
		  "m"(e), "m"(f), "m"(g), "m"(h)      \
		: "%rax","%rcx","%rdx","%rsi","%rdi", \
		  "%r8","%r9","%r10","%r11"	      \
		)

#define HCALL32(rc,id,a,b,c,d,e,f,g,h)		      \
  asm volatile ("movl %1, %%eax; "		      \
		"pushl %%ebx; "			      \
		"movl $0x32323232, %%ebx; "	      \
		"pushl %9;"			      \
		"pushl %8;"			      \
		"pushl %7;"			      \
		"pushl %6;"			      \
		"pushl %5;"			      \
		"pushl %4;"			      \
		"pushl %3;"			      \
		"pushl %2;"			      \
		"vmmcall ;       "		      \
		"movl %%eax, %0; "		      \
		"movl %%ebx, %1; "                    \
		"addl $32, %%esp; "		      \
		"popl %%ebx; "			      \
		: "=m"(rc), "=m"(id)		      \
		: "m"(a), "m"(b), "m"(c), "m"(d),      \
		"m"(e), "m"(f), "m"(g), "m"(h)	      \
		: "%eax"			      \
		)

#ifdef __x86_64__
#define HCALL(rc,id,a,b,c,d,e,f,g,h)  HCALL64(rc,id,a,b,c,d,e,f,g,h)
#else
#define HCALL(rc,id,a,b,c,d,e,f,g,h)  HCALL32(rc,id,a,b,c,d,e,f,g,h)   
#endif

#endif