From: Mark Wielaard Date: Sun, 21 May 2017 21:33:15 +0000 (+0200) Subject: ppc64: Add minimal fallback unwinder. X-Git-Tag: elfutils-0.170~23 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=660aafcf78818424248faccf2ccab4ac9deee582;p=thirdparty%2Felfutils.git ppc64: Add minimal fallback unwinder. This adds a minimal fallback unwinder for ppc64[le] in case we cannot find CFI for a particular address. It simply always sets the program counter to the link register, picks the previous stack pointer from the backchain, and the previous link register from the LR save area. This is enough for some simple situations when we don't have CFI and seems to work nicely in the case of perf with libdw powerpc support: https://lkml.org/lkml/2017/5/18/998 Signed-off-by: Mark Wielaard --- diff --git a/backends/ChangeLog b/backends/ChangeLog index 1ac5bab3a..f0d29f62e 100644 --- a/backends/ChangeLog +++ b/backends/ChangeLog @@ -1,3 +1,9 @@ +2017-05-30 Mark Wielaard + + * ppc64_unwind.c: New file. + * ppc64_init.c (pcc64_init): Hook unwind. + * Makefile.am (ppc64_SRCS): Add ppc64_unwind.c + 2017-04-06 Mark Wielaard * i386_unwind.c: New file. diff --git a/backends/Makefile.am b/backends/Makefile.am index ff80a82c0..ac45a452b 100644 --- a/backends/Makefile.am +++ b/backends/Makefile.am @@ -98,7 +98,7 @@ am_libebl_ppc_pic_a_OBJECTS = $(ppc_SRCS:.c=.os) ppc64_SRCS = ppc64_init.c ppc64_symbol.c ppc64_retval.c \ ppc64_corenote.c ppc_regs.c ppc_auxv.c ppc_attrs.c ppc_syscall.c \ - ppc_cfi.c ppc_initreg.c ppc64_resolve_sym.c + ppc_cfi.c ppc_initreg.c ppc64_unwind.c ppc64_resolve_sym.c libebl_ppc64_pic_a_SOURCES = $(ppc64_SRCS) am_libebl_ppc64_pic_a_OBJECTS = $(ppc64_SRCS:.c=.os) diff --git a/backends/ppc64_init.c b/backends/ppc64_init.c index 11d3a77ff..e5670338c 100644 --- a/backends/ppc64_init.c +++ b/backends/ppc64_init.c @@ -73,6 +73,7 @@ ppc64_init (Elf *elf __attribute__ ((unused)), eh->frame_nregs = (114 - 1) + 32; HOOK (eh, set_initial_registers_tid); HOOK (eh, dwarf_to_regno); + HOOK (eh, unwind); HOOK (eh, resolve_sym_value); /* Find the function descriptor .opd table for resolve_sym_value. */ diff --git a/backends/ppc64_unwind.c b/backends/ppc64_unwind.c new file mode 100644 index 000000000..4fa0b5a96 --- /dev/null +++ b/backends/ppc64_unwind.c @@ -0,0 +1,76 @@ +/* Get previous frame state for an existing frame state. + Copyright (C) 2017 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 . */ + +#ifdef HAVE_CONFIG_H +# include +#endif + +#define BACKEND ppc64_ + +#define LR_REG 65 /* Not 108, see ppc_dwarf_to_regno. */ +#define SP_REG 1 + +#define LR_OFFSET 16 + +#include "libebl_CPU.h" + +/* Simplistic fallback frame unwinder. SP points to the backchain (contains + address of previous stack pointer). At SP offset 16 is the LR save area + (contains the value of the previous LR). */ + +bool +EBLHOOK(unwind) (Ebl *ebl __attribute__ ((unused)), + Dwarf_Addr pc __attribute__ ((unused)), + ebl_tid_registers_t *setfunc, ebl_tid_registers_get_t *getfunc, + ebl_pid_memory_read_t *readfunc, void *arg, + bool *signal_framep __attribute__ ((unused))) +{ + Dwarf_Word sp, newSp, lr, newLr; + + /* Stack pointer points to the backchain which contains the previous sp. */ + if (! getfunc (SP_REG, 1, &sp, arg)) + sp = 0; + + /* Link register contains previous program counter. */ + if (! getfunc (LR_REG, 1, &lr, arg) + || lr == 0 + || ! setfunc (-1, 1, &lr, arg)) + return false; + + if (! readfunc(sp, &newSp, arg)) + newSp = 0; + + if (! readfunc(newSp + LR_OFFSET, &newLr, arg)) + newLr = 0; + + setfunc(SP_REG, 1, &newSp, arg); + setfunc(LR_REG, 1, &newLr, arg); + + /* Sanity check the stack grows down. */ + return newSp > sp; +} diff --git a/tests/ChangeLog b/tests/ChangeLog index 5b0d486e2..43b5bd8a8 100644 --- a/tests/ChangeLog +++ b/tests/ChangeLog @@ -1,3 +1,13 @@ +2017-05-30 Mark Wielaard + + * run-backtrace-fp-core-ppc64le.sh: New test. + * backtrace.ppc64le.fp.core.bz2: New test file. + * backtrace.ppc64le.fp.exec.bz2: New testfile. + * backtrace-subr.sh (check_backtracegen): Accept '(null)'. + * Makefile.am (TESTS): Add run-backtrace-fp-core-ppc64le.sh. + (EXTRA_DIST): Add run-backtrace-fp-core-ppc64le.sh, + backtrace.ppc64le.fp.core.bz2 and backtrace.ppc64le.fp.exec.bz2. + 2017-02-13 Ulf Hermann Mark Wielaard diff --git a/tests/Makefile.am b/tests/Makefile.am index 3a12fe3a8..50648db88 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -117,6 +117,7 @@ TESTS = run-arextract.sh run-arsymtest.sh newfile test-nlist \ run-backtrace-native-core-biarch.sh run-backtrace-core-x86_64.sh \ run-backtrace-fp-core-x86_64.sh \ run-backtrace-fp-core-aarch64.sh \ + run-backtrace-fp-core-ppc64le.sh \ run-backtrace-core-x32.sh \ run-backtrace-core-i386.sh run-backtrace-fp-core-i386.sh \ run-backtrace-core-ppc.sh \ @@ -303,6 +304,8 @@ EXTRA_DIST = run-arextract.sh run-arsymtest.sh \ backtrace-subr.sh backtrace.i386.core.bz2 backtrace.i386.exec.bz2 \ run-backtrace-fp-core-i386.sh \ backtrace.i386.fp.core.bz2 backtrace.i386.fp.exec.bz2 \ + run-backtrace-fp-core-ppc64le.sh \ + backtrace.ppc64le.fp.core.bz2 backtrace.ppc64le.fp.exec.bz2 \ backtrace.x86_64.core.bz2 backtrace.x86_64.exec.bz2 \ backtrace.x86_64.fp.core.bz2 backtrace.x86_64.fp.exec.bz2 \ backtrace.ppc.core.bz2 backtrace.ppc.exec.bz2 \ diff --git a/tests/backtrace-subr.sh b/tests/backtrace-subr.sh index 9731c43aa..c1f315691 100644 --- a/tests/backtrace-subr.sh +++ b/tests/backtrace-subr.sh @@ -59,7 +59,7 @@ check_backtracegen() # Ignore it here as it is a bug of OS, not a bug of elfutils. check_err() { - if [ $(egrep -v <$1 'dwfl_thread_getframes: (No DWARF information found|no matching address range|address out of range|Invalid register)$' \ + if [ $(egrep -v <$1 'dwfl_thread_getframes: (No DWARF information found|no matching address range|address out of range|Invalid register|\(null\))$' \ | wc -c) \ -eq 0 ] then diff --git a/tests/backtrace.ppc64le.fp.core.bz2 b/tests/backtrace.ppc64le.fp.core.bz2 new file mode 100644 index 000000000..e63babf38 Binary files /dev/null and b/tests/backtrace.ppc64le.fp.core.bz2 differ diff --git a/tests/backtrace.ppc64le.fp.exec.bz2 b/tests/backtrace.ppc64le.fp.exec.bz2 new file mode 100755 index 000000000..ed1352af6 Binary files /dev/null and b/tests/backtrace.ppc64le.fp.exec.bz2 differ diff --git a/tests/run-backtrace-fp-core-ppc64le.sh b/tests/run-backtrace-fp-core-ppc64le.sh new file mode 100755 index 000000000..326ca342d --- /dev/null +++ b/tests/run-backtrace-fp-core-ppc64le.sh @@ -0,0 +1,29 @@ +#! /bin/bash +# Copyright (C) 2017 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 the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. +# +# 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 a copy of the GNU General Public License +# along with this program. If not, see . + +. $srcdir/backtrace-subr.sh + +# The binary is generated by compiling backtrace-child without unwind +# information, but with -fno-omit-frame-pointer. +# +# gcc -static -O2 -fno-omit-frame-pointer -fno-asynchronous-unwind-tables \ +# -D_GNU_SOURCE -pthread -o tests/backtrace.ppc64le.fp.exec -I. -Ilib \ +# tests/backtrace-child.c +# +# The core is generated by calling tests/backtrace.ppc64le.fp.exec --gencore + +check_core ppc64le.fp