274 lines
9.4 KiB
C
274 lines
9.4 KiB
C
/* DWARF2 EH unwinding support for TPF OS.
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Copyright (C) 2004-2017 Free Software Foundation, Inc.
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Contributed by P.J. Darcy (darcypj@us.ibm.com).
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include <dlfcn.h>
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#include <stdbool.h>
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/* Function Name: __isPATrange
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Parameters passed into it: address to check
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Return Value: A 1 if address is in pat code "range", 0 if not
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Description: This function simply checks to see if the address
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passed to it is in the CP pat code range. */
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#define MIN_PATRANGE 0x10000
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#define MAX_PATRANGE 0x800000
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static inline unsigned int
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__isPATrange (void *addr)
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{
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if (addr > (void *)MIN_PATRANGE && addr < (void *)MAX_PATRANGE)
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return 1;
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else
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return 0;
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}
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/* TPF return address offset from start of stack frame. */
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#define TPFRA_OFFSET 168
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/* Exceptions macro defined for TPF so that functions without
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dwarf frame information can be used with exceptions. */
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#define MD_FALLBACK_FRAME_STATE_FOR s390_fallback_frame_state
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static _Unwind_Reason_Code
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s390_fallback_frame_state (struct _Unwind_Context *context,
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_Unwind_FrameState *fs)
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{
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unsigned long int regs;
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unsigned long int new_cfa;
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int i;
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regs = *((unsigned long int *)
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(((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
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/* Are we going through special linkage code? */
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if (__isPATrange (context->ra))
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{
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/* Our return register isn't zero for end of stack, so
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check backward stackpointer to see if it is zero. */
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if (regs == NULL)
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return _URC_END_OF_STACK;
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/* No stack frame. */
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = 15;
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fs->regs.cfa_offset = STACK_POINTER_OFFSET;
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/* All registers remain unchanged ... */
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for (i = 0; i < 32; i++)
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{
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fs->regs.reg[i].how = REG_SAVED_REG;
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fs->regs.reg[i].loc.reg = i;
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}
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/* ... except for %r14, which is stored at CFA-112
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and used as return address. */
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fs->regs.reg[14].how = REG_SAVED_OFFSET;
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fs->regs.reg[14].loc.offset = TPFRA_OFFSET - STACK_POINTER_OFFSET;
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fs->retaddr_column = 14;
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return _URC_NO_REASON;
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}
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regs = *((unsigned long int *)
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(((unsigned long int) context->cfa) - STACK_POINTER_OFFSET));
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new_cfa = regs + STACK_POINTER_OFFSET;
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fs->regs.cfa_how = CFA_REG_OFFSET;
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fs->regs.cfa_reg = 15;
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fs->regs.cfa_offset = new_cfa -
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(unsigned long int) context->cfa + STACK_POINTER_OFFSET;
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for (i = 0; i < 16; i++)
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{
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fs->regs.reg[i].how = REG_SAVED_OFFSET;
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fs->regs.reg[i].loc.offset = regs + i*8 - new_cfa;
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}
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for (i = 0; i < 4; i++)
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{
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fs->regs.reg[16 + i].how = REG_SAVED_OFFSET;
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fs->regs.reg[16 + i].loc.offset = regs + 16*8 + i*8 - new_cfa;
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}
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fs->retaddr_column = 14;
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return _URC_NO_REASON;
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}
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/* Function Name: __tpf_eh_return
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Parameters passed into it: Destination address to jump to.
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Return Value: Converted Destination address if a Pat Stub exists.
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Description: This function swaps the unwinding return address
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with the cp stub code. The original target return address is
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then stored into the tpf return address field. The cp stub
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code is searched for by climbing back up the stack and
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comparing the tpf stored return address object address to
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that of the targets object address. */
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#define CURRENT_STACK_PTR() \
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({ register unsigned long int *stack_ptr asm ("%r15"); stack_ptr; })
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#define PREVIOUS_STACK_PTR() \
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((unsigned long int *)(*(CURRENT_STACK_PTR())))
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#define RA_OFFSET 112
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#define R15_OFFSET 120
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#define TPFAREA_OFFSET 160
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#define TPFAREA_SIZE STACK_POINTER_OFFSET-TPFAREA_OFFSET
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#define INVALID_RETURN 0
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void * __tpf_eh_return (void *target, void *origRA);
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void *
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__tpf_eh_return (void *target, void *origRA)
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{
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Dl_info targetcodeInfo, currentcodeInfo;
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int retval;
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void *current, *stackptr, *destination_frame;
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unsigned long int shifter;
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bool is_a_stub, frameDepth2, firstIteration;
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is_a_stub = false;
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frameDepth2 = false;
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firstIteration = true;
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/* Get code info for target return's address. */
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retval = dladdr (target, &targetcodeInfo);
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/* Check if original RA is a Pat stub. If so set flag. */
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if (__isPATrange (origRA))
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frameDepth2 = true;
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/* Ensure the code info is valid (for target). */
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if (retval != INVALID_RETURN)
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{
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/* Get the stack pointer of the first stack frame beyond the
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unwinder or if exists the calling C++ runtime function (e.g.,
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__cxa_throw). */
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if (!frameDepth2)
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stackptr = (void *) *((unsigned long int *) (*(PREVIOUS_STACK_PTR())));
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else
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stackptr = (void *) *(PREVIOUS_STACK_PTR());
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/* Begin looping through stack frames. Stop if invalid
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code information is retrieved or if a match between the
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current stack frame iteration shared object's address
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matches that of the target, calculated above. */
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do
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{
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if (!frameDepth2 || (frameDepth2 && !firstIteration))
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{
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/* Get return address based on our stackptr iterator. */
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current = (void *) *((unsigned long int *)
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(stackptr + RA_OFFSET));
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/* Is it a Pat Stub? */
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if (__isPATrange (current))
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{
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/* Yes it was, get real return address in TPF stack area. */
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current = (void *) *((unsigned long int *)
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(stackptr + TPFRA_OFFSET))
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is_a_stub = true;
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}
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}
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else
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{
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current = (void *) *((unsigned long int *)
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(stackptr + TPFRA_OFFSET));
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is_a_stub = true;
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}
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/* Get codeinfo on RA so that we can figure out
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the module address. */
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retval = dladdr (current, ¤tcodeInfo);
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/* Check that codeinfo for current stack frame is valid.
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Then compare the module address of current stack frame
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to target stack frame to determine if we have the pat
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stub address we want. Also ensure we are dealing
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with a module crossing, stub return address. */
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if (is_a_stub && retval != INVALID_RETURN
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&& targetcodeInfo.dli_fbase == currentcodeInfo.dli_fbase)
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{
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/* Yes! They are in the same module.
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Force copy of TPF private stack area to
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destination stack frame TPF private area. */
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destination_frame = (void *) *((unsigned long int *)
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(*PREVIOUS_STACK_PTR() + R15_OFFSET));
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/* Copy TPF linkage area from current frame to
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destination frame. */
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memcpy((void *) (destination_frame + TPFAREA_OFFSET),
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(void *) (stackptr + TPFAREA_OFFSET), TPFAREA_SIZE);
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/* Now overlay the
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real target address into the TPF stack area of
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the target frame we are jumping to. */
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*((unsigned long int *) (destination_frame +
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TPFRA_OFFSET)) = (unsigned long int) target;
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/* Before returning the desired pat stub address to
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the exception handling unwinder so that it can
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actually do the "leap" shift out the low order
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bit designated to determine if we are in 64BIT mode.
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This is necessary for CTOA stubs.
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Otherwise we leap one byte past where we want to
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go to in the TPF pat stub linkage code. */
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if (!frameDepth2 || (frameDepth2 && !firstIteration))
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shifter = *((unsigned long int *) (stackptr + RA_OFFSET));
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else
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shifter = (unsigned long int) origRA;
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shifter &= ~1ul;
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/* Store Pat Stub Address in destination Stack Frame. */
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*((unsigned long int *) (destination_frame +
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RA_OFFSET)) = shifter;
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/* Re-adjust pat stub address to go to correct place
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in linkage. */
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shifter = shifter - 4;
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return (void *) shifter;
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}
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/* Desired module pat stub not found ...
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Bump stack frame iterator. */
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stackptr = (void *) *(unsigned long int *) stackptr;
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is_a_stub = false;
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firstIteration = false;
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} while (stackptr && retval != INVALID_RETURN
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&& targetcodeInfo.dli_fbase != currentcodeInfo.dli_fbase);
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}
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/* No pat stub found, could be a problem? Simply return unmodified
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target address. */
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return target;
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}
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