/* DWARF2 EH unwinding support for SPARC Linux.
Copyright (C) 2004-2020 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. */
#if defined(__arch64__)
#undef STACK_BIAS
#define STACK_BIAS 2047
/* 64-bit SPARC version */
#define MD_FALLBACK_FRAME_STATE_FOR sparc64_fallback_frame_state
static _Unwind_Reason_Code
sparc64_fallback_frame_state (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
unsigned int *pc = context->ra;
long this_cfa = (long) context->cfa;
long new_cfa, ra_location, shifted_ra_location;
long regs_off, fpu_save_off;
long fpu_save;
int i;
if (pc[0] != 0x82102065 /* mov NR_rt_sigreturn, %g1 */
|| pc[1] != 0x91d0206d) /* ta 0x6d */
return _URC_END_OF_STACK;
regs_off = 192 + 128;
fpu_save_off = regs_off + (16 * 8) + (3 * 8) + (2 * 4);
new_cfa = *(long *)(this_cfa + regs_off + (14 * 8));
/* The frame address is %sp + STACK_BIAS in 64-bit mode. */
new_cfa += STACK_BIAS;
fpu_save = *(long *)(this_cfa + fpu_save_off);
fs->regs.cfa_how = CFA_REG_OFFSET;
fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
fs->regs.cfa_offset = new_cfa - this_cfa;
for (i = 1; i < 16; i++)
{
/* We never restore %sp as everything is purely CFA-based. */
if ((unsigned int) i == __builtin_dwarf_sp_column ())
continue;
fs->regs.reg[i].how = REG_SAVED_OFFSET;
fs->regs.reg[i].loc.offset
= this_cfa + regs_off + (i * 8) - new_cfa;
}
for (i = 0; i < 16; i++)
{
fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;
fs->regs.reg[i + 16].loc.offset
= this_cfa + (i * 8) - new_cfa;
}
if (fpu_save)
{
for (i = 0; i < 64; i++)
{
if (i > 32 && (i & 0x1))
continue;
fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
fs->regs.reg[i + 32].loc.offset
= fpu_save + (i * 4) - new_cfa;
}
}
/* State the rules to find the kernel's code "return address", which is
the address of the active instruction when the signal was caught.
On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we
need to preventively subtract it from the purported return address. */
ra_location = this_cfa + regs_off + 17 * 8;
shifted_ra_location = this_cfa + regs_off + 19 * 8; /* Y register */
*(long *)shifted_ra_location = *(long *)ra_location - 8;
fs->retaddr_column = 0;
fs->regs.reg[0].how = REG_SAVED_OFFSET;
fs->regs.reg[0].loc.offset = shifted_ra_location - new_cfa;
fs->signal_frame = 1;
return _URC_NO_REASON;
}
#define MD_FROB_UPDATE_CONTEXT sparc64_frob_update_context
static void
sparc64_frob_update_context (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
/* The column of %sp contains the old CFA, not the old value of %sp.
The CFA offset already comprises the stack bias so, when %sp is the
CFA register, we must avoid counting the stack bias twice. Do not
do that for signal frames as the offset is artificial for them. */
if (fs->regs.cfa_reg == __builtin_dwarf_sp_column ()
&& fs->regs.cfa_how == CFA_REG_OFFSET
&& fs->regs.cfa_offset != 0
&& !fs->signal_frame)
{
long i;
context->cfa -= STACK_BIAS;
for (i = 0; i < __LIBGCC_DWARF_FRAME_REGISTERS__ + 1; ++i)
if (fs->regs.reg[i].how == REG_SAVED_OFFSET)
_Unwind_SetGRPtr (context, i,
_Unwind_GetGRPtr (context, i) - STACK_BIAS);
}
}
#else
/* 32-bit SPARC version */
#define MD_FALLBACK_FRAME_STATE_FOR sparc_fallback_frame_state
static _Unwind_Reason_Code
sparc_fallback_frame_state (struct _Unwind_Context *context,
_Unwind_FrameState *fs)
{
unsigned int *pc = context->ra;
int this_cfa = (int) context->cfa;
int new_cfa, ra_location, shifted_ra_location;
int regs_off, fpu_save_off;
int fpu_save;
int old_style, i;
if (pc[1] != 0x91d02010) /* ta 0x10 */
return _URC_END_OF_STACK;
if (pc[0] == 0x821020d8) /* mov NR_sigreturn, %g1 */
old_style = 1;
else if (pc[0] == 0x82102065) /* mov NR_rt_sigreturn, %g1 */
old_style = 0;
else
return _URC_END_OF_STACK;
if (old_style)
{
regs_off = 96;
fpu_save_off = regs_off + (4 * 4) + (16 * 4);
}
else
{
regs_off = 96 + 128;
fpu_save_off = regs_off + (4 * 4) + (16 * 4) + (2 * 4);
}
new_cfa = *(int *)(this_cfa + regs_off + (4 * 4) + (14 * 4));
fpu_save = *(int *)(this_cfa + fpu_save_off);
fs->regs.cfa_how = CFA_REG_OFFSET;
fs->regs.cfa_reg = __builtin_dwarf_sp_column ();
fs->regs.cfa_offset = new_cfa - this_cfa;
for (i = 1; i < 16; i++)
{
/* We never restore %sp as everything is purely CFA-based. */
if ((unsigned int) i == __builtin_dwarf_sp_column ())
continue;
fs->regs.reg[i].how = REG_SAVED_OFFSET;
fs->regs.reg[i].loc.offset
= this_cfa + regs_off + (4 * 4) + (i * 4) - new_cfa;
}
for (i = 0; i < 16; i++)
{
fs->regs.reg[i + 16].how = REG_SAVED_OFFSET;
fs->regs.reg[i + 16].loc.offset
= this_cfa + (i * 4) - new_cfa;
}
if (fpu_save)
{
for (i = 0; i < 32; i++)
{
fs->regs.reg[i + 32].how = REG_SAVED_OFFSET;
fs->regs.reg[i + 32].loc.offset
= fpu_save + (i * 4) - new_cfa;
}
}
/* State the rules to find the kernel's code "return address", which is
the address of the active instruction when the signal was caught.
On the SPARC, since RETURN_ADDR_OFFSET (essentially 8) is defined, we
need to preventively subtract it from the purported return address. */
ra_location = this_cfa + regs_off + 4;
shifted_ra_location = this_cfa + regs_off + 3 * 4; /* Y register */
*(int *)shifted_ra_location = *(int *)ra_location - 8;
fs->retaddr_column = 0;
fs->regs.reg[0].how = REG_SAVED_OFFSET;
fs->regs.reg[0].loc.offset = shifted_ra_location - new_cfa;
fs->signal_frame = 1;
return _URC_NO_REASON;
}
#endif