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Diffstat (limited to 'src/backends/s390_unwind.c')
| -rw-r--r-- | src/backends/s390_unwind.c | 139 |
1 files changed, 139 insertions, 0 deletions
diff --git a/src/backends/s390_unwind.c b/src/backends/s390_unwind.c new file mode 100644 index 00000000..752bc287 --- /dev/null +++ b/src/backends/s390_unwind.c @@ -0,0 +1,139 @@ +/* Get previous frame state for an existing frame state. + Copyright (C) 2013 Red Hat, Inc. + This file is part of elfutils. + + This file is free software; you can redistribute it and/or modify + it under the terms of either + + * the GNU Lesser General Public License as published by the Free + Software Foundation; either version 3 of the License, or (at + your option) any later version + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at + your option) any later version + + or both in parallel, as here. + + elfutils 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. + + You should have received copies of the GNU General Public License and + the GNU Lesser General Public License along with this program. If + not, see <http://www.gnu.org/licenses/>. */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#include <stdlib.h> +#include <assert.h> + +#define BACKEND s390_ +#include "libebl_CPU.h" + +/* s390/s390x do not annotate signal handler frame by CFI. It would be also + difficult as PC points into a stub built on stack. Function below is called + only if unwinder could not find CFI. Function then verifies the register + state for this frame really belongs to a signal frame. In such case it + fetches original registers saved by the signal frame. */ + +bool +s390_unwind (Ebl *ebl, Dwarf_Addr pc, ebl_tid_registers_t *setfunc, + ebl_tid_registers_get_t *getfunc, ebl_pid_memory_read_t *readfunc, + void *arg, bool *signal_framep) +{ + /* Caller already assumed caller adjustment but S390 instructions are 4 bytes + long. Undo it. */ + if ((pc & 0x3) != 0x3) + return false; + pc++; + /* We can assume big-endian read here. */ + Dwarf_Word instr; + if (! readfunc (pc, &instr, arg)) + return false; + /* Fetch only the very first two bytes. */ + instr = (instr >> (ebl->class == ELFCLASS64 ? 48 : 16)) & 0xffff; + /* See GDB s390_sigtramp_frame_sniffer. */ + /* Check for 'svc' as the first instruction. */ + if (((instr >> 8) & 0xff) != 0x0a) + return false; + /* Check for 'sigreturn' or 'rt_sigreturn' as the second instruction. */ + if ((instr & 0xff) != 119 && (instr & 0xff) != 173) + return false; + /* See GDB s390_sigtramp_frame_unwind_cache. */ + Dwarf_Word this_sp; + if (! getfunc (0 + 15, 1, &this_sp, arg)) + return false; + unsigned word_size = ebl->class == ELFCLASS64 ? 8 : 4; + Dwarf_Addr next_cfa = this_sp + 16 * word_size + 32; + /* "New-style RT frame" is not supported, + assuming "Old-style RT frame and all non-RT frames". + Pointer to the array of saved registers is at NEXT_CFA + 8. */ + Dwarf_Word sigreg_ptr; + if (! readfunc (next_cfa + 8, &sigreg_ptr, arg)) + return false; + /* Skip PSW mask. */ + sigreg_ptr += word_size; + /* Read PSW address. */ + Dwarf_Word val; + if (! readfunc (sigreg_ptr, &val, arg)) + return false; + if (! setfunc (-1, 1, &val, arg)) + return false; + sigreg_ptr += word_size; + /* Then the GPRs. */ + Dwarf_Word gprs[16]; + for (int i = 0; i < 16; i++) + { + if (! readfunc (sigreg_ptr, &gprs[i], arg)) + return false; + sigreg_ptr += word_size; + } + /* Then the ACRs. Skip them, they are not used in CFI. */ + for (int i = 0; i < 16; i++) + sigreg_ptr += 4; + /* The floating-point control word. */ + sigreg_ptr += 8; + /* And finally the FPRs. */ + Dwarf_Word fprs[16]; + for (int i = 0; i < 16; i++) + { + if (! readfunc (sigreg_ptr, &val, arg)) + return false; + if (ebl->class == ELFCLASS32) + { + Dwarf_Addr val_low; + if (! readfunc (sigreg_ptr + 4, &val_low, arg)) + return false; + val = (val << 32) | val_low; + } + fprs[i] = val; + sigreg_ptr += 8; + } + /* If we have them, the GPR upper halves are appended at the end. */ + if (ebl->class == ELFCLASS32) + { + /* Skip signal number. */ + sigreg_ptr += 4; + for (int i = 0; i < 16; i++) + { + if (! readfunc (sigreg_ptr, &val, arg)) + return false; + Dwarf_Word val_low = gprs[i]; + val = (val << 32) | val_low; + gprs[i] = val; + sigreg_ptr += 4; + } + } + if (! setfunc (0, 16, gprs, arg)) + return false; + if (! setfunc (16, 16, fprs, arg)) + return false; + *signal_framep = true; + return true; +} |