/* DWARF2 EH unwinding support for PA HP-UX.
   Copyright (C) 2005-2021 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3, or (at your option)
any later version.

GCC is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.

You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
<http://www.gnu.org/licenses/>.  */

/* Do code reading to identify a signal frame, and set the frame
   state data appropriately.  See unwind-dw2.c for the structs.  */

/* Don't use this if inhibit_libc is set.
   The build for this target will fail trying to include missing headers. */
#ifndef inhibit_libc
#include <signal.h>
#include <sys/ucontext.h>
#include <unistd.h>

/* FIXME: We currently ignore the high halves of general, space and
   control registers on PA 2.0 machines for applications using the
   32-bit runtime.  We don't restore space registers or the floating
   point status registers.  */

#define MD_FALLBACK_FRAME_STATE_FOR pa_fallback_frame_state

/* HP-UX 10.X doesn't define GetSSReg.  */
#ifndef GetSSReg
#define GetSSReg(ssp, ss_reg) \
  ((UseWideRegs (ssp))							\
   ? (ssp)->ss_wide.ss_32.ss_reg ## _lo					\
   : (ssp)->ss_narrow.ss_reg)
#endif

#if TARGET_64BIT
#define GetSSRegAddr(ssp, ss_reg) ((long) &((ssp)->ss_wide.ss_64.ss_reg))
#else
#define GetSSRegAddr(ssp, ss_reg) \
  ((UseWideRegs (ssp))							\
   ? (long) &((ssp)->ss_wide.ss_32.ss_reg ## _lo)			\
   : (long) &((ssp)->ss_narrow.ss_reg))
#endif

#define UPDATE_FS_FOR_SAR(FS, N) \
  (FS)->regs.reg[N].how = REG_SAVED_OFFSET;				\
  (FS)->regs.reg[N].loc.offset = GetSSRegAddr (mc, ss_cr11) - new_cfa

#define UPDATE_FS_FOR_GR(FS, GRN, N) \
  (FS)->regs.reg[N].how = REG_SAVED_OFFSET;				\
  (FS)->regs.reg[N].loc.offset = GetSSRegAddr (mc, ss_gr##GRN) - new_cfa

#define UPDATE_FS_FOR_FR(FS, FRN, N) \
  (FS)->regs.reg[N].how = REG_SAVED_OFFSET;				\
  (FS)->regs.reg[N].loc.offset = (long) &(mc->ss_fr##FRN) - new_cfa;

#define UPDATE_FS_FOR_PC(FS, N) \
  (FS)->regs.reg[N].how = REG_SAVED_OFFSET;				\
  (FS)->regs.reg[N].loc.offset = GetSSRegAddr (mc, ss_pcoq_head) - new_cfa

/* Extract bit field from word using HP's numbering (MSB = 0).  */
#define GET_FIELD(X, FROM, TO) \
  ((X) >> (31 - (TO)) & ((1 << ((TO) - (FROM) + 1)) - 1))

static inline int
sign_extend (int x, int len)
{
  int signbit = (1 << (len - 1));
  int mask = (signbit << 1) - 1;
  return ((x & mask) ^ signbit) - signbit;
}

/* Extract a 17-bit signed constant from branch instructions.  */
static inline int
extract_17 (unsigned word)
{
  return sign_extend (GET_FIELD (word, 19, 28)
		      | GET_FIELD (word, 29, 29) << 10
		      | GET_FIELD (word, 11, 15) << 11
		      | (word & 0x1) << 16, 17);
}

/* Extract a 22-bit signed constant from branch instructions.  */
static inline int
extract_22 (unsigned word)
{
  return sign_extend (GET_FIELD (word, 19, 28)
		      | GET_FIELD (word, 29, 29) << 10
		      | GET_FIELD (word, 11, 15) << 11
		      | GET_FIELD (word, 6, 10) << 16
		      | (word & 0x1) << 21, 22);
}

static _Unwind_Reason_Code
pa_fallback_frame_state (struct _Unwind_Context *context,
			 _Unwind_FrameState *fs)
{
  static long cpu;
  unsigned int *pc = (unsigned int *) context->ra;

  if (pc == 0)
    return _URC_END_OF_STACK;

  /* Check for relocation of the return value.  */
  if (!TARGET_64BIT
      && *(pc + 0) == 0x2fd01224		/* fstd,ma fr4,8(sp) */
      && *(pc + 1) == 0x0fd9109d		/* ldw -4(sp),ret1 */
      && *(pc + 2) == 0x0fd130bc)		/* ldw,mb -8(sp),ret0 */
    pc += 3;
  else if (!TARGET_64BIT
	   && *(pc + 0) == 0x27d01224		/* fstw,ma fr4,8(sp) */
	   && *(pc + 1) == 0x0fd130bc)		/* ldw,mb -8(sp),ret0 */
    pc += 2;
  else if (!TARGET_64BIT
	   && *(pc + 0) == 0x0fdc12b0		/* stw,ma ret0,8(sp) */
	   && *(pc + 1) == 0x0fdd1299		/* stw ret1,-4(sp) */
	   && *(pc + 2) == 0x2fd13024)		/* fldd,mb -8(sp),fr4 */
    pc += 3;
  else if (!TARGET_64BIT
	   && *(pc + 0) == 0x0fdc12b0		/* stw,ma ret0,8(sp) */
	   && *(pc + 1) == 0x27d13024)		/* fldw,mb -8(sp),fr4 */
    pc += 2;

  /* Check if the return address points to an export stub (PA 1.1 or 2.0).  */
  if ((!TARGET_64BIT
       && *(pc + 0) == 0x4bc23fd1		/* ldw -18(sp),rp */
       && *(pc + 1) == 0x004010a1		/* ldsid (rp),r1 */
       && *(pc + 2) == 0x00011820		/* mtsp r1,sr0 */
       && *(pc + 3) == 0xe0400002)		/* be,n 0(sr0,rp) */
      ||
      (!TARGET_64BIT
       && *(pc + 0) == 0x4bc23fd1		/* ldw -18(sp),rp */
       && *(pc + 1) == 0xe840d002))		/* bve,n (rp) */
    {
      fs->regs.cfa_how    = CFA_REG_OFFSET;
      fs->regs.cfa_reg    = 30;
      fs->regs.cfa_offset = 0;

      fs->retaddr_column = 0;
      fs->regs.reg[0].how = REG_SAVED_OFFSET;
      fs->regs.reg[0].loc.offset = -24;

      /* Update context to describe the stub frame.  */
      uw_update_context (context, fs);

      /* Set up fs to describe the FDE for the caller of this stub.  */
      return uw_frame_state_for (context, fs);
    }
  /* Check if the return address points to a relocation stub.  */
  else if (!TARGET_64BIT
	   && *(pc + 0) == 0x0fd11082		/* ldw -8(sp),rp */
	   && (*(pc + 1) == 0xe840c002		/* bv,n r0(rp) */
	       || *(pc + 1) == 0xe840d002))	/* bve,n (rp) */
    {
      fs->regs.cfa_how    = CFA_REG_OFFSET;
      fs->regs.cfa_reg    = 30;
      fs->regs.cfa_offset = 0;

      fs->retaddr_column = 0;
      fs->regs.reg[0].how = REG_SAVED_OFFSET;
      fs->regs.reg[0].loc.offset = -8;

      /* Update context to describe the stub frame.  */
      uw_update_context (context, fs);

      /* Set up fs to describe the FDE for the caller of this stub.  */
      return uw_frame_state_for (context, fs);
    }

  /* Check if the return address is an export stub as signal handlers
     may return via an export stub.  */
  if (!TARGET_64BIT
      && (*pc & 0xffe0e002) == 0xe8400000	/* bl x,r2 */
      && *(pc + 1) == 0x08000240		/* nop */
      && *(pc + 2) == 0x4bc23fd1		/* ldw -18(sp),rp */
      && *(pc + 3) == 0x004010a1		/* ldsid (rp),r1 */
      && *(pc + 4) == 0x00011820		/* mtsp r1,sr0 */
      && *(pc + 5) == 0xe0400002)		/* be,n 0(sr0,rp) */
    /* Extract target address from PA 1.x 17-bit branch.  */
    pc += extract_17 (*pc) + 2;
  else if (!TARGET_64BIT
	   && (*pc & 0xfc00e002) == 0xe800a000	/* b,l x,r2 */
	   && *(pc + 1) == 0x08000240		/* nop */
	   && *(pc + 2) == 0x4bc23fd1		/* ldw -18(sp),rp */
	   && *(pc + 3) == 0xe840d002)		/* bve,n (rp) */
    /* Extract target address from PA 2.0 22-bit branch.  */
    pc += extract_22 (*pc) + 2;

  /* Now check if the return address is one of the signal handler
     returns, _sigreturn or _sigsetreturn.  */
  if ((TARGET_64BIT
       && *(pc + 0)  == 0x53db3f51		/* ldd -58(sp),dp */
       && *(pc + 8)  == 0x34160116		/* ldi 8b,r22 */
       && *(pc + 9)  == 0x08360ac1		/* shladd,l r22,3,r1,r1 */
       && *(pc + 10) == 0x0c2010c1		/* ldd 0(r1),r1 */
       && *(pc + 11) == 0xe4202000)		/* be,l 0(sr4,r1) */
      ||
      (TARGET_64BIT
       && *(pc + 0)  == 0x36dc0000		/* ldo 0(r22),ret0 */
       && *(pc + 6)  == 0x341601c0		/* ldi e0,r22 */
       && *(pc + 7)  == 0x08360ac1		/* shladd,l r22,3,r1,r1 */
       && *(pc + 8)  == 0x0c2010c1		/* ldd 0(r1),r1 */
       && *(pc + 9)  == 0xe4202000)		/* be,l 0(sr4,r1) */
      ||
      (!TARGET_64BIT
       && *(pc + 0)  == 0x379a0000		/* ldo 0(ret0),r26 */
       && *(pc + 1)  == 0x6bd33fc9		/* stw r19,-1c(sp) */
       && *(pc + 2)  == 0x20200801		/* ldil L%-40000000,r1 */
       && *(pc + 3)  == 0xe420e008		/* be,l 4(sr7,r1) */
       && *(pc + 4)  == 0x34160116)		/* ldi 8b,r22 */
      ||
      (!TARGET_64BIT
       && *(pc + 0)  == 0x6bd33fc9		/* stw r19,-1c(sp) */
       && *(pc + 1)  == 0x20200801		/* ldil L%-40000000,r1 */
       && *(pc + 2)  == 0xe420e008		/* be,l 4(sr7,r1) */
       && *(pc + 3)  == 0x341601c0))		/* ldi e0,r22 */
    {
      /* The previous stack pointer is saved at (long *)SP - 1.  The
	 ucontext structure is offset from the start of the previous
	 frame by the siglocal_misc structure.  */
      struct siglocalx *sl = (struct siglocalx *)
	(*((long *) context->cfa - 1));
      mcontext_t *mc = &(sl->sl_uc.uc_mcontext);

      long new_cfa = GetSSReg (mc, ss_sp);

      fs->regs.cfa_how = CFA_REG_OFFSET;
      fs->regs.cfa_reg = 30;
      fs->regs.cfa_offset = new_cfa - (long) context->cfa;

      UPDATE_FS_FOR_GR (fs, 1, 1);
      UPDATE_FS_FOR_GR (fs, 2, 2);
      UPDATE_FS_FOR_GR (fs, 3, 3);
      UPDATE_FS_FOR_GR (fs, 4, 4);
      UPDATE_FS_FOR_GR (fs, 5, 5);
      UPDATE_FS_FOR_GR (fs, 6, 6);
      UPDATE_FS_FOR_GR (fs, 7, 7);
      UPDATE_FS_FOR_GR (fs, 8, 8);
      UPDATE_FS_FOR_GR (fs, 9, 9);
      UPDATE_FS_FOR_GR (fs, 10, 10);
      UPDATE_FS_FOR_GR (fs, 11, 11);
      UPDATE_FS_FOR_GR (fs, 12, 12);
      UPDATE_FS_FOR_GR (fs, 13, 13);
      UPDATE_FS_FOR_GR (fs, 14, 14);
      UPDATE_FS_FOR_GR (fs, 15, 15);
      UPDATE_FS_FOR_GR (fs, 16, 16);
      UPDATE_FS_FOR_GR (fs, 17, 17);
      UPDATE_FS_FOR_GR (fs, 18, 18);
      UPDATE_FS_FOR_GR (fs, 19, 19);
      UPDATE_FS_FOR_GR (fs, 20, 20);
      UPDATE_FS_FOR_GR (fs, 21, 21);
      UPDATE_FS_FOR_GR (fs, 22, 22);
      UPDATE_FS_FOR_GR (fs, 23, 23);
      UPDATE_FS_FOR_GR (fs, 24, 24);
      UPDATE_FS_FOR_GR (fs, 25, 25);
      UPDATE_FS_FOR_GR (fs, 26, 26);
      UPDATE_FS_FOR_GR (fs, 27, 27);
      UPDATE_FS_FOR_GR (fs, 28, 28);
      UPDATE_FS_FOR_GR (fs, 29, 29);
      UPDATE_FS_FOR_GR (fs, 30, 30);
      UPDATE_FS_FOR_GR (fs, 31, 31);

      if (TARGET_64BIT)
	{
	  UPDATE_FS_FOR_FR (fs, 4, 32);
	  UPDATE_FS_FOR_FR (fs, 5, 33);
	  UPDATE_FS_FOR_FR (fs, 6, 34);
	  UPDATE_FS_FOR_FR (fs, 7, 35);
	  UPDATE_FS_FOR_FR (fs, 8, 36);
	  UPDATE_FS_FOR_FR (fs, 9, 37);
	  UPDATE_FS_FOR_FR (fs, 10, 38);
	  UPDATE_FS_FOR_FR (fs, 11, 39);
	  UPDATE_FS_FOR_FR (fs, 12, 40);
	  UPDATE_FS_FOR_FR (fs, 13, 41);
	  UPDATE_FS_FOR_FR (fs, 14, 42);
	  UPDATE_FS_FOR_FR (fs, 15, 43);
	  UPDATE_FS_FOR_FR (fs, 16, 44);
	  UPDATE_FS_FOR_FR (fs, 17, 45);
	  UPDATE_FS_FOR_FR (fs, 18, 46);
	  UPDATE_FS_FOR_FR (fs, 19, 47);
	  UPDATE_FS_FOR_FR (fs, 20, 48);
	  UPDATE_FS_FOR_FR (fs, 21, 49);
	  UPDATE_FS_FOR_FR (fs, 22, 50);
	  UPDATE_FS_FOR_FR (fs, 23, 51);
	  UPDATE_FS_FOR_FR (fs, 24, 52);
	  UPDATE_FS_FOR_FR (fs, 25, 53);
	  UPDATE_FS_FOR_FR (fs, 26, 54);
	  UPDATE_FS_FOR_FR (fs, 27, 55);
	  UPDATE_FS_FOR_FR (fs, 28, 56);
	  UPDATE_FS_FOR_FR (fs, 29, 57);
	  UPDATE_FS_FOR_FR (fs, 30, 58);
	  UPDATE_FS_FOR_FR (fs, 31, 59);

	  UPDATE_FS_FOR_SAR (fs, 60);
	}
      else
	{
	  UPDATE_FS_FOR_FR (fs, 4, 32);
	  UPDATE_FS_FOR_FR (fs, 5, 34);
	  UPDATE_FS_FOR_FR (fs, 6, 36);
	  UPDATE_FS_FOR_FR (fs, 7, 38);
	  UPDATE_FS_FOR_FR (fs, 8, 40);
	  UPDATE_FS_FOR_FR (fs, 9, 44);
	  UPDATE_FS_FOR_FR (fs, 10, 44);
	  UPDATE_FS_FOR_FR (fs, 11, 46);
	  UPDATE_FS_FOR_FR (fs, 12, 48);
	  UPDATE_FS_FOR_FR (fs, 13, 50);
	  UPDATE_FS_FOR_FR (fs, 14, 52);
	  UPDATE_FS_FOR_FR (fs, 15, 54);

	  if (!cpu)
	    cpu = sysconf (_SC_CPU_VERSION);

	  /* PA-RISC 1.0 only has 16 floating point registers.  */
	  if (cpu != CPU_PA_RISC1_0)
	    {
	      UPDATE_FS_FOR_FR (fs, 16, 56);
	      UPDATE_FS_FOR_FR (fs, 17, 58);
	      UPDATE_FS_FOR_FR (fs, 18, 60);
	      UPDATE_FS_FOR_FR (fs, 19, 62);
	      UPDATE_FS_FOR_FR (fs, 20, 64);
	      UPDATE_FS_FOR_FR (fs, 21, 66);
	      UPDATE_FS_FOR_FR (fs, 22, 68);
	      UPDATE_FS_FOR_FR (fs, 23, 70);
	      UPDATE_FS_FOR_FR (fs, 24, 72);
	      UPDATE_FS_FOR_FR (fs, 25, 74);
	      UPDATE_FS_FOR_FR (fs, 26, 76);
	      UPDATE_FS_FOR_FR (fs, 27, 78);
	      UPDATE_FS_FOR_FR (fs, 28, 80);
	      UPDATE_FS_FOR_FR (fs, 29, 82);
	      UPDATE_FS_FOR_FR (fs, 30, 84);
	      UPDATE_FS_FOR_FR (fs, 31, 86);
	    }

	  UPDATE_FS_FOR_SAR (fs, 88);
	}

      fs->retaddr_column = __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__;
      UPDATE_FS_FOR_PC (fs, __LIBGCC_DWARF_ALT_FRAME_RETURN_COLUMN__);
      fs->signal_frame = 1;

      return _URC_NO_REASON;
    }

  return _URC_END_OF_STACK;
}
#endif /* inhibit_libc */