/* ARM EABI compliant unwinding routines
Copyright (C) 2004-2020 Free Software Foundation, Inc.
Contributed by Paul Brook
This file 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.
This file 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/>. */
#pragma GCC target ("general-regs-only")
#include "unwind.h"
/* We add a prototype for abort here to avoid creating a dependency on
target headers. */
extern void abort (void);
typedef struct _ZSt9type_info type_info; /* This names C++ type_info type */
/* Misc constants. */
#define R_IP 12
#define R_SP 13
#define R_LR 14
#define R_PC 15
#define uint32_highbit (((_uw) 1) << 31)
void __attribute__((weak)) __cxa_call_unexpected(_Unwind_Control_Block *ucbp);
/* Unwind descriptors. */
typedef struct
{
_uw16 length;
_uw16 offset;
} EHT16;
typedef struct
{
_uw length;
_uw offset;
} EHT32;
/* Calculate the address encoded by a 31-bit self-relative offset at address
P. Copy of routine in unwind-arm.c. */
static inline _uw
selfrel_offset31 (const _uw *p)
{
_uw offset;
offset = *p;
/* Sign extend to 32 bits. */
if (offset & (1 << 30))
offset |= 1u << 31;
return offset + (_uw) p;
}
/* Personality routine helper functions. */
#define CODE_FINISH (0xb0)
/* Return the next byte of unwinding information, or CODE_FINISH if there is
no data remaining. */
static inline _uw8
next_unwind_byte (__gnu_unwind_state * uws)
{
_uw8 b;
if (uws->bytes_left == 0)
{
/* Load another word */
if (uws->words_left == 0)
return CODE_FINISH; /* Nothing left. */
uws->words_left--;
uws->data = *(uws->next++);
uws->bytes_left = 3;
}
else
uws->bytes_left--;
/* Extract the most significant byte. */
b = (uws->data >> 24) & 0xff;
uws->data <<= 8;
return b;
}
/* Execute the unwinding instructions described by UWS. */
_Unwind_Reason_Code
__gnu_unwind_execute (_Unwind_Context * context, __gnu_unwind_state * uws)
{
_uw op;
int set_pc;
_uw reg;
set_pc = 0;
for (;;)
{
op = next_unwind_byte (uws);
if (op == CODE_FINISH)
{
/* If we haven't already set pc then copy it from lr. */
if (!set_pc)
{
_Unwind_VRS_Get (context, _UVRSC_CORE, R_LR, _UVRSD_UINT32,
®);
_Unwind_VRS_Set (context, _UVRSC_CORE, R_PC, _UVRSD_UINT32,
®);
set_pc = 1;
}
/* Drop out of the loop. */
break;
}
if ((op & 0x80) == 0)
{
/* vsp = vsp +- (imm6 << 2 + 4). */
_uw offset;
offset = ((op & 0x3f) << 2) + 4;
_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
if (op & 0x40)
reg -= offset;
else
reg += offset;
_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
continue;
}
if ((op & 0xf0) == 0x80)
{
op = (op << 8) | next_unwind_byte (uws);
if (op == 0x8000)
{
/* Refuse to unwind. */
return _URC_FAILURE;
}
/* Pop r4-r15 under mask. */
op = (op << 4) & 0xfff0;
if (_Unwind_VRS_Pop (context, _UVRSC_CORE, op, _UVRSD_UINT32)
!= _UVRSR_OK)
return _URC_FAILURE;
if (op & (1 << R_PC))
set_pc = 1;
continue;
}
if ((op & 0xf0) == 0x90)
{
op &= 0xf;
if (op == 13 || op == 15)
/* Reserved. */
return _URC_FAILURE;
/* vsp = r[nnnn]. */
_Unwind_VRS_Get (context, _UVRSC_CORE, op, _UVRSD_UINT32, ®);
_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32, ®);
continue;
}
if ((op & 0xf0) == 0xa0)
{
/* Pop r4-r[4+nnn], [lr]. */
_uw mask;
mask = (0xff0 >> (7 - (op & 7))) & 0xff0;
if (op & 8)
mask |= (1 << R_LR);
if (_Unwind_VRS_Pop (context, _UVRSC_CORE, mask, _UVRSD_UINT32)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if ((op & 0xf0) == 0xb0)
{
/* op == 0xb0 already handled. */
if (op == 0xb1)
{
op = next_unwind_byte (uws);
if (op == 0 || ((op & 0xf0) != 0))
/* Spare. */
return _URC_FAILURE;
/* Pop r0-r4 under mask. */
if (_Unwind_VRS_Pop (context, _UVRSC_CORE, op, _UVRSD_UINT32)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if (op == 0xb2)
{
/* vsp = vsp + 0x204 + (uleb128 << 2). */
int shift;
_Unwind_VRS_Get (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
®);
op = next_unwind_byte (uws);
shift = 2;
while (op & 0x80)
{
reg += ((op & 0x7f) << shift);
shift += 7;
op = next_unwind_byte (uws);
}
reg += ((op & 0x7f) << shift) + 0x204;
_Unwind_VRS_Set (context, _UVRSC_CORE, R_SP, _UVRSD_UINT32,
®);
continue;
}
if (op == 0xb3)
{
/* Pop VFP registers with fldmx. */
op = next_unwind_byte (uws);
op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_VFPX)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if ((op & 0xfc) == 0xb4) /* Obsolete FPA. */
return _URC_FAILURE;
/* op & 0xf8 == 0xb8. */
/* Pop VFP D[8]-D[8+nnn] with fldmx. */
op = 0x80000 | ((op & 7) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_VFPX)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if ((op & 0xf0) == 0xc0)
{
if (op == 0xc6)
{
/* Pop iWMMXt D registers. */
op = next_unwind_byte (uws);
op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_WMMXD, op, _UVRSD_UINT64)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if (op == 0xc7)
{
op = next_unwind_byte (uws);
if (op == 0 || (op & 0xf0) != 0)
/* Spare. */
return _URC_FAILURE;
/* Pop iWMMXt wCGR{3,2,1,0} under mask. */
if (_Unwind_VRS_Pop (context, _UVRSC_WMMXC, op, _UVRSD_UINT32)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if ((op & 0xf8) == 0xc0)
{
/* Pop iWMMXt wR[10]-wR[10+nnn]. */
op = 0xa0000 | ((op & 0xf) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_WMMXD, op, _UVRSD_UINT64)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if (op == 0xc8)
{
/* Pop VFPv3 registers D[16+ssss]-D[16+ssss+cccc] with vldm. */
op = next_unwind_byte (uws);
op = (((op & 0xf0) + 16) << 12) | ((op & 0xf) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
if (op == 0xc9)
{
/* Pop VFP registers with fldmd. */
op = next_unwind_byte (uws);
op = ((op & 0xf0) << 12) | ((op & 0xf) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
/* Spare. */
return _URC_FAILURE;
}
if ((op & 0xf8) == 0xd0)
{
/* Pop VFP D[8]-D[8+nnn] with fldmd. */
op = 0x80000 | ((op & 7) + 1);
if (_Unwind_VRS_Pop (context, _UVRSC_VFP, op, _UVRSD_DOUBLE)
!= _UVRSR_OK)
return _URC_FAILURE;
continue;
}
/* Spare. */
return _URC_FAILURE;
}
return _URC_OK;
}
/* Execute the unwinding instructions associated with a frame. UCBP and
CONTEXT are the current exception object and virtual CPU state
respectively. */
_Unwind_Reason_Code
__gnu_unwind_frame (_Unwind_Control_Block * ucbp, _Unwind_Context * context)
{
_uw *ptr;
__gnu_unwind_state uws;
ptr = (_uw *) ucbp->pr_cache.ehtp;
/* Skip over the personality routine address. */
ptr++;
/* Setup the unwinder state. */
uws.data = (*ptr) << 8;
uws.next = ptr + 1;
uws.bytes_left = 3;
uws.words_left = ((*ptr) >> 24) & 0xff;
return __gnu_unwind_execute (context, &uws);
}
/* Get the _Unwind_Control_Block from an _Unwind_Context. */
static inline _Unwind_Control_Block *
unwind_UCB_from_context (_Unwind_Context * context)
{
return (_Unwind_Control_Block *) _Unwind_GetGR (context, R_IP);
}
/* Get the start address of the function being unwound. */
_Unwind_Ptr
_Unwind_GetRegionStart (_Unwind_Context * context)
{
_Unwind_Control_Block *ucbp;
ucbp = unwind_UCB_from_context (context);
return (_Unwind_Ptr) ucbp->pr_cache.fnstart;
}
/* Find the Language specific exception data. */
_Unwind_Ptr
_Unwind_GetLanguageSpecificData (_Unwind_Context * context)
{
_Unwind_Control_Block *ucbp;
_uw *ptr;
/* Get a pointer to the exception table entry. */
ucbp = unwind_UCB_from_context (context);
ptr = (_uw *) ucbp->pr_cache.ehtp;
/* Skip the personality routine address. */
ptr++;
/* Skip the unwind opcodes. */
ptr += (((*ptr) >> 24) & 0xff) + 1;
return (_Unwind_Ptr) ptr;
}
/* These two should never be used. */
_Unwind_Ptr
_Unwind_GetDataRelBase (_Unwind_Context *context __attribute__ ((unused)))
{
abort ();
}
_Unwind_Ptr
_Unwind_GetTextRelBase (_Unwind_Context *context __attribute__ ((unused)))
{
abort ();
}