/*
* Copyright 1988, 1989 Hans-J. Boehm, Alan J. Demers
* Copyright (c) 1991-1994 by Xerox Corporation.  All rights reserved.
*
* THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
* OR IMPLIED.  ANY USE IS AT YOUR OWN RISK.
*
* Permission is hereby granted to use or copy this program
* for any purpose,  provided the above notices are retained on all copies.
* Permission to modify the code and to distribute modified code is granted,
* provided the above notices are retained, and a notice that the code was
* modified is included with the above copyright notice.
*/

#include "private/gc_priv.h"

#if !defined(PLATFORM_MACH_DEP) && !defined(SN_TARGET_PSP2)

#include <stdio.h>

#ifdef AMIGA
# ifndef __GNUC__
#   include <dos.h>
# else
#   include <machine/reg.h>
# endif
#endif

#ifdef E2K
# include <errno.h>
# include <asm/e2k_syswork.h>
# include <sys/mman.h>
# include <sys/syscall.h>

 GC_INNER size_t GC_get_procedure_stack(ptr_t buf, size_t buf_sz) {
   word new_sz;

   GC_ASSERT(0 == buf_sz || buf != NULL);
   for (;;) {
     word stack_ofs;

     new_sz = 0;
     if (syscall(__NR_access_hw_stacks, E2K_GET_PROCEDURE_STACK_SIZE,
                 NULL, NULL, 0, &new_sz) == -1) {
       if (errno != EAGAIN)
         ABORT_ARG1("Cannot get size of procedure stack",
                    ": errno= %d", errno);
       continue;
     }
     GC_ASSERT(new_sz > 0 && new_sz % sizeof(word) == 0);
     if (new_sz > buf_sz)
       break;
     /* Immediately read the stack right after checking its size. */
     stack_ofs = 0;
     if (syscall(__NR_access_hw_stacks, E2K_READ_PROCEDURE_STACK_EX,
                 &stack_ofs, buf, new_sz, NULL) != -1)
       break;
     if (errno != EAGAIN)
       ABORT_ARG2("Cannot read procedure stack",
                  ": new_sz= %lu, errno= %d", (unsigned long)new_sz, errno);
   }
   return (size_t)new_sz;
 }

 ptr_t GC_save_regs_in_stack(void) {
   __asm__ __volatile__ ("flushr");
   return NULL;
 }

 GC_INNER ptr_t GC_mmap_procedure_stack_buf(size_t aligned_sz)
 {
   void *buf = mmap(NULL, aligned_sz, PROT_READ | PROT_WRITE,
                    MAP_PRIVATE | MAP_ANON, 0 /* fd */, 0 /* offset */);
   if (MAP_FAILED == buf)
     ABORT_ARG2("Could not map memory for procedure stack",
                ": requested %lu bytes, errno= %d",
                (unsigned long)aligned_sz, errno);
   return (ptr_t)buf;
 }

 GC_INNER void GC_unmap_procedure_stack_buf(ptr_t buf, size_t sz)
 {
   if (munmap(buf, ROUNDUP_PAGESIZE(sz)) == -1)
     ABORT_ARG1("munmap failed (for procedure stack space)",
                ": errno= %d", errno);
 }

# ifdef THREADS
   GC_INNER size_t GC_alloc_and_get_procedure_stack(ptr_t *pbuf)
   {
     /* TODO: support saving from non-zero ofs in stack */
     ptr_t buf = NULL;
     size_t new_sz, buf_sz;

     GC_ASSERT(I_HOLD_LOCK());
     for (buf_sz = 0; ; buf_sz = new_sz) {
       new_sz = GC_get_procedure_stack(buf, buf_sz);
       if (new_sz <= buf_sz) break;

       if (EXPECT(buf != NULL, FALSE))
         GC_INTERNAL_FREE(buf);
       buf = (ptr_t)GC_INTERNAL_MALLOC_IGNORE_OFF_PAGE(new_sz, PTRFREE);
       if (NULL == buf)
         ABORT("Could not allocate memory for procedure stack");
     }
     *pbuf = buf;
     return new_sz;
   }
# endif /* THREADS */
#endif /* E2K */

#if defined(MACOS) && defined(__MWERKS__)

#if defined(POWERPC)

# define NONVOLATILE_GPR_COUNT 19
 struct ppc_registers {
       unsigned long gprs[NONVOLATILE_GPR_COUNT];      /* R13-R31 */
 };
 typedef struct ppc_registers ppc_registers;

# if defined(CPPCHECK)
   void getRegisters(ppc_registers* regs);
# else
   asm static void getRegisters(register ppc_registers* regs)
   {
       stmw    r13,regs->gprs                          /* save R13-R31 */
       blr
   }
# endif

 static void PushMacRegisters(void)
 {
       ppc_registers regs;
       int i;
       getRegisters(&regs);
       for (i = 0; i < NONVOLATILE_GPR_COUNT; i++)
               GC_push_one(regs.gprs[i]);
 }

#else /* M68K */

 asm static void PushMacRegisters(void)
 {
   sub.w   #4,sp                   /* reserve space for one parameter */
   move.l  a2,(sp)
   jsr         GC_push_one
   move.l  a3,(sp)
   jsr         GC_push_one
   move.l  a4,(sp)
   jsr         GC_push_one
#   if !__option(a6frames)
     /* <pcb> perhaps a6 should be pushed if stack frames are not being used */
       move.l  a6,(sp)
       jsr             GC_push_one
#   endif
       /* skip a5 (globals), a6 (frame pointer), and a7 (stack pointer) */
   move.l  d2,(sp)
   jsr         GC_push_one
   move.l  d3,(sp)
   jsr         GC_push_one
   move.l  d4,(sp)
   jsr         GC_push_one
   move.l  d5,(sp)
   jsr         GC_push_one
   move.l  d6,(sp)
   jsr         GC_push_one
   move.l  d7,(sp)
   jsr         GC_push_one
   add.w   #4,sp                   /* fix stack */
   rts
 }

#endif /* M68K */

#endif /* MACOS && __MWERKS__ */

# if defined(SPARC) || defined(IA64)
   /* Value returned from register flushing routine; either sp (SPARC) */
   /* or ar.bsp (IA64).                                                */
   GC_INNER ptr_t GC_save_regs_ret_val = NULL;
# endif

/* Routine to mark from registers that are preserved by the C compiler. */
/* This must be ported to every new architecture.  It is not optional,  */
/* and should not be used on platforms that are either UNIX-like, or    */
/* require thread support.                                              */

#undef HAVE_PUSH_REGS

#if defined(USE_ASM_PUSH_REGS)
# define HAVE_PUSH_REGS
#else  /* No asm implementation */

# ifdef STACK_NOT_SCANNED
   void GC_push_regs(void)
   {
     /* empty */
   }
#   define HAVE_PUSH_REGS

# elif defined(M68K) && defined(AMIGA)
   /* This function is not static because it could also be             */
   /* erroneously defined in .S file, so this error would be caught    */
   /* by the linker.                                                   */
   void GC_push_regs(void)
   {
        /*  AMIGA - could be replaced by generic code                  */
        /* a0, a1, d0 and d1 are caller save */

#       ifdef __GNUC__
         asm("subq.w &0x4,%sp");       /* allocate word on top of stack */

         asm("mov.l %a2,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %a3,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %a4,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %a5,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %a6,(%sp)"); asm("jsr _GC_push_one");
         /* Skip frame pointer and stack pointer */
         asm("mov.l %d2,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %d3,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %d4,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %d5,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %d6,(%sp)"); asm("jsr _GC_push_one");
         asm("mov.l %d7,(%sp)"); asm("jsr _GC_push_one");

         asm("addq.w &0x4,%sp");       /* put stack back where it was  */
#       else /* !__GNUC__ */
         GC_push_one(getreg(REG_A2));
         GC_push_one(getreg(REG_A3));
#         ifndef __SASC
           /* Can probably be changed to #if 0 -Kjetil M. (a4=globals) */
           GC_push_one(getreg(REG_A4));
#         endif
         GC_push_one(getreg(REG_A5));
         GC_push_one(getreg(REG_A6));
         /* Skip stack pointer */
         GC_push_one(getreg(REG_D2));
         GC_push_one(getreg(REG_D3));
         GC_push_one(getreg(REG_D4));
         GC_push_one(getreg(REG_D5));
         GC_push_one(getreg(REG_D6));
         GC_push_one(getreg(REG_D7));
#       endif /* !__GNUC__ */
   }
#   define HAVE_PUSH_REGS

# elif defined(MACOS)

#   if defined(M68K) && defined(THINK_C) && !defined(CPPCHECK)
#     define PushMacReg(reg) \
             move.l  reg,(sp) \
             jsr             GC_push_one
     void GC_push_regs(void)
     {
         asm {
             sub.w   #4,sp          ; reserve space for one parameter.
             PushMacReg(a2);
             PushMacReg(a3);
             PushMacReg(a4);
             ; skip a5 (globals), a6 (frame pointer), and a7 (stack pointer)
             PushMacReg(d2);
             PushMacReg(d3);
             PushMacReg(d4);
             PushMacReg(d5);
             PushMacReg(d6);
             PushMacReg(d7);
             add.w   #4,sp          ; fix stack.
         }
     }
#     define HAVE_PUSH_REGS
#     undef PushMacReg
#   elif defined(__MWERKS__)
     void GC_push_regs(void)
     {
         PushMacRegisters();
     }
#     define HAVE_PUSH_REGS
#   endif /* __MWERKS__ */
# endif /* MACOS */

#endif /* !USE_ASM_PUSH_REGS */

#if defined(HAVE_PUSH_REGS) && defined(THREADS)
# error GC_push_regs cannot be used with threads
/* Would fail for GC_do_blocking.  There are probably other safety     */
/* issues.                                                             */
# undef HAVE_PUSH_REGS
#endif

#if !defined(HAVE_PUSH_REGS) && defined(UNIX_LIKE)
# include <signal.h>
# ifndef NO_GETCONTEXT
#   if defined(DARWIN) \
      && (MAC_OS_X_VERSION_MAX_ALLOWED >= 1060 /*MAC_OS_X_VERSION_10_6*/)
#     include <sys/ucontext.h>
#   else
#     include <ucontext.h>
#   endif /* !DARWIN */
#   ifdef GETCONTEXT_FPU_EXCMASK_BUG
#     include <fenv.h>
#   endif
# endif
#endif /* !HAVE_PUSH_REGS */

/* Ensure that either registers are pushed, or callee-save registers    */
/* are somewhere on the stack, and then call fn(arg, ctxt).             */
/* ctxt is either a pointer to a ucontext_t we generated, or NULL.      */
GC_ATTR_NO_SANITIZE_ADDR
GC_INNER void GC_with_callee_saves_pushed(void (*fn)(ptr_t, void *),
                                         volatile ptr_t arg)
{
 volatile int dummy;
 volatile ptr_t context = 0;

# if defined(HAVE_PUSH_REGS)
   GC_push_regs();
# elif defined(EMSCRIPTEN)
   /* No-op, "registers" are pushed in GC_push_other_roots().  */
# else
#   if defined(UNIX_LIKE) && !defined(NO_GETCONTEXT)
     /* Older versions of Darwin seem to lack getcontext().    */
     /* ARM and MIPS Linux often doesn't support a real        */
     /* getcontext().                                          */
     static signed char getcontext_works = 0; /* (-1) - broken, 1 - works */
     ucontext_t ctxt;
#     ifdef GETCONTEXT_FPU_EXCMASK_BUG
       /* Workaround a bug (clearing the FPU exception mask) in        */
       /* getcontext on Linux/x64.                                     */
#       ifdef X86_64
         /* We manipulate FPU control word here just not to force the  */
         /* client application to use -lm linker option.               */
         unsigned short old_fcw;

#         if defined(CPPCHECK)
           GC_noop1((word)&old_fcw);
#         endif
         __asm__ __volatile__ ("fstcw %0" : "=m" (*&old_fcw));
#       else
         int except_mask = fegetexcept();
#       endif
#     endif

     if (getcontext_works >= 0) {
       if (getcontext(&ctxt) < 0) {
         WARN("getcontext failed:"
              " using another register retrieval method...\n", 0);
         /* getcontext() is broken, do not try again.          */
         /* E.g., to workaround a bug in Docker ubuntu_32bit.  */
       } else {
         context = (ptr_t)&ctxt;
       }
       if (EXPECT(0 == getcontext_works, FALSE))
         getcontext_works = context != NULL ? 1 : -1;
     }
#     ifdef GETCONTEXT_FPU_EXCMASK_BUG
#       ifdef X86_64
         __asm__ __volatile__ ("fldcw %0" : : "m" (*&old_fcw));
         {
           unsigned mxcsr;
           /* And now correct the exception mask in SSE MXCSR. */
           __asm__ __volatile__ ("stmxcsr %0" : "=m" (*&mxcsr));
           mxcsr = (mxcsr & ~(FE_ALL_EXCEPT << 7)) |
                       ((old_fcw & FE_ALL_EXCEPT) << 7);
           __asm__ __volatile__ ("ldmxcsr %0" : : "m" (*&mxcsr));
         }
#       else /* !X86_64 */
         if (feenableexcept(except_mask) < 0)
           ABORT("feenableexcept failed");
#       endif
#     endif /* GETCONTEXT_FPU_EXCMASK_BUG */
#     if defined(E2K) || defined(IA64) || defined(SPARC)
       /* On a register window machine, we need to save register       */
       /* contents on the stack for this to work.  This may already be */
       /* subsumed by the getcontext() call.                           */
#       if defined(IA64) || defined(SPARC)
         GC_save_regs_ret_val =
#       endif
           GC_save_regs_in_stack();
#     endif
     if (NULL == context) /* getcontext failed */
#   endif /* !NO_GETCONTEXT */
   {
#     if defined(HAVE_BUILTIN_UNWIND_INIT)
       /* This was suggested by Richard Henderson as the way to        */
       /* force callee-save registers and register windows onto        */
       /* the stack.                                                   */
       __builtin_unwind_init();
#     elif defined(NO_CRT) && defined(MSWIN32)
       CONTEXT ctx;
       RtlCaptureContext(&ctx);
#     else
       /* Generic code                          */
       /* The idea is due to Parag Patel at HP. */
       /* We're not sure whether he would like  */
       /* to be acknowledged for it or not.     */
       jmp_buf regs;
       word *i = (word *)&regs[0];
       ptr_t lim = (ptr_t)(&regs[0]) + sizeof(regs);

       /* Setjmp doesn't always clear all of the buffer.               */
       /* That tends to preserve garbage.  Clear it.                   */
       for (; (word)i < (word)lim; i++) {
           *i = 0;
       }
#       if defined(MSWIN32) || defined(MSWINCE) || defined(UTS4) \
          || defined(OS2) || defined(CX_UX) || defined(__CC_ARM) \
          || defined(LINUX) || defined(EWS4800) || defined(RTEMS) \
          || defined(DJGPP)
         (void) setjmp(regs);
#       else
         (void) _setjmp(regs);
         /* We don't want to mess with signals. According to   */
         /* SUSV3, setjmp() may or may not save signal mask.   */
         /* _setjmp won't, but is less portable.               */
#       endif
#     endif /* !HAVE_BUILTIN_UNWIND_INIT */
   }
# endif /* !HAVE_PUSH_REGS */
 /* TODO: context here is sometimes just zero.  At the moment, the     */
 /* callees don't really need it.                                      */
 fn(arg, (/* no volatile */ void *)context);
 /* Strongly discourage the compiler from treating the above   */
 /* as a tail-call, since that would pop the register          */
 /* contents before we get a chance to look at them.           */
 GC_noop1(COVERT_DATAFLOW(&dummy));
}

#endif /* !PLATFORM_MACH_DEP && !SN_TARGET_PSP2 */

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