gears/services/devfile/hcall.h

   1 /*
   2    Device File Virtualization Guest Preload Library Helpers
   3
   4    (c) Akhil Guliani and William Gross, 2015
   5
   6    Adapted from MPI module (c) 2012 Peter Dinda
   7
   8    Note that the calling convention here is a bit different
   9    since we need to return errno
  10
  11
  12 */
  13
  14 #ifndef __HCALL__
  15 #define __HCALL__
  16
  17 /*
  18   Calling convention:
  19
  20 64 bit:
  21   rax = hcall number
  22   rbx = 0x6464646464646464...
  23   rcx = 1st arg
  24   rdx = 2nd arg
  25   rsi = 3rd arg
  26   rdi = 4th arg
  27   r8  = 5th arg
  28   r9  = 6th arg
  29   r10 = 7th arg
  30   r11 = 8th arg
  31
  32 32 bit:
  33   eax = hcall number
  34   ebx = 0x32323232
  35   arguments on stack in C order (first argument is TOS)
  36      arguments are also 32 bit
  37
  38 In this convention,
  39   RAX is assumed to be the return code from the system call
  40   RBX is assumed to be the errno set by the system call
  41
  42   RAX comes back via rc
  43   RBX comes back via overwrite of id
  44 */
  45 #define HCALL64(rc,id,a,b,c,d,e,f,g,h)                \
  46   asm volatile ("movq %1, %%rax; "                    \
  47                 "pushq %%rbx; "                       \
  48                 "movq $0x6464646464646464, %%rbx; "   \
  49                 "movq %2, %%rcx; "                    \
  50                 "movq %3, %%rdx; "                    \
  51                 "movq %4, %%rsi; "                    \
  52                 "movq %5, %%rdi; "                    \
  53                 "movq %6, %%r8 ; "                    \
  54                 "movq %7, %%r9 ; "                    \
  55                 "movq %8, %%r10; "                    \
  56                 "movq %9, %%r11; "                    \
  57                 "vmmcall ;       "                    \
  58                 "movq %%rax, %0; "                    \
  59                 "movq %%rbx, %1; "                    \
  60                 "popq %%rbx; "                        \
  61                 : "=m"(rc),"=m"(id)                   \
  62                 : "m"(a), "m"(b), "m"(c), "m"(d),      \
  63                   "m"(e), "m"(f), "m"(g), "m"(h)      \
  64                 : "%rax","%rcx","%rdx","%rsi","%rdi", \
  65                   "%r8","%r9","%r10","%r11"           \
  66                 )
  67
  68 #define HCALL32(rc,id,a,b,c,d,e,f,g,h)                \
  69   asm volatile ("movl %1, %%eax; "                    \
  70                 "pushl %%ebx; "                       \
  71                 "movl $0x32323232, %%ebx; "           \
  72                 "pushl %9;"                           \
  73                 "pushl %8;"                           \
  74                 "pushl %7;"                           \
  75                 "pushl %6;"                           \
  76                 "pushl %5;"                           \
  77                 "pushl %4;"                           \
  78                 "pushl %3;"                           \
  79                 "pushl %2;"                           \
  80                 "vmmcall ;       "                    \
  81                 "movl %%eax, %0; "                    \
  82                 "movl %%ebx, %1; "                    \
  83                 "addl $32, %%esp; "                   \
  84                 "popl %%ebx; "                        \
  85                 : "=m"(rc), "=m"(id)                  \
  86                 : "m"(a), "m"(b), "m"(c), "m"(d),      \
  87                 "m"(e), "m"(f), "m"(g), "m"(h)        \
  88                 : "%eax"                              \
  89                 )
  90
  91 #ifdef __x86_64__
  92 #define HCALL(rc,id,a,b,c,d,e,f,g,h)  HCALL64(rc,id,a,b,c,d,e,f,g,h)
  93 #else
  94 #define HCALL(rc,id,a,b,c,d,e,f,g,h)  HCALL32(rc,id,a,b,c,d,e,f,g,h)
  95 #endif
  96
  97 #endif