From 5046dbb4a7eba5eccfd258f92f4735c9ffc8d069 Mon Sep 17 00:00:00 2001 From: Zack Weinberg Date: Thu, 8 Jun 2017 15:39:03 -0400 Subject: Prepare for radical source tree reorganization. All top-level files and directories are moved into a temporary storage directory, REORG.TODO, except for files that will certainly still exist in their current form at top level when we're done (COPYING, COPYING.LIB, LICENSES, NEWS, README), all old ChangeLog files (which are moved to the new directory OldChangeLogs, instead), and the generated file INSTALL (which is just deleted; in the new order, there will be no generated files checked into version control). --- REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c | 131 +++++++++++++++++++++++ 1 file changed, 131 insertions(+) create mode 100644 REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c (limited to 'REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c') diff --git a/REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c b/REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c new file mode 100644 index 0000000000..394062136c --- /dev/null +++ b/REORG.TODO/sysdeps/powerpc/powerpc32/backtrace.c @@ -0,0 +1,131 @@ +/* Return backtrace of current program state. + Copyright (C) 1998-2017 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#include +#include +#include +#include +#include + +/* This is the stack layout we see with every stack frame. + Note that every routine is required by the ABI to lay out the stack + like this. + + +----------------+ +-----------------+ + %r1 -> | %r1 last frame--------> | %r1 last frame--->... --> NULL + | | | | + | (unused) | | return address | + +----------------+ +-----------------+ +*/ +struct layout +{ + struct layout *next; + void *return_address; +}; + +#define SIGNAL_FRAMESIZE 64 + +/* Since the signal handler is just like any other function it needs to + save/restore its LR and it will save it into callers stack frame. + Since a signal handler doesn't have a caller, the kernel creates a + dummy frame to make it look like it has a caller. */ +struct signal_frame_32 { + char dummy[SIGNAL_FRAMESIZE]; + struct sigcontext sctx; + mcontext_t mctx; + /* We don't care about the rest, since IP value is at 'mctx' field. */ +}; + +static inline int +is_sigtramp_address (void *nip) +{ +#ifdef SHARED + if (nip == VDSO_SYMBOL (sigtramp32)) + return 1; +#endif + return 0; +} + +struct rt_signal_frame_32 { + char dummy[SIGNAL_FRAMESIZE + 16]; + siginfo_t info; + struct ucontext uc; + /* We don't care about the rest, since IP value is at 'uc' field. */ +}; + +static inline int +is_sigtramp_address_rt (void * nip) +{ +#ifdef SHARED + if (nip == VDSO_SYMBOL (sigtramp_rt32)) + return 1; +#endif + return 0; +} + +int +__backtrace (void **array, int size) +{ + struct layout *current; + int count; + + /* Force gcc to spill LR. */ + asm volatile ("" : "=l"(current)); + + /* Get the address on top-of-stack. */ + asm volatile ("lwz %0,0(1)" : "=r"(current)); + + for ( count = 0; + current != NULL && count < size; + current = current->next, count++) + { + gregset_t *gregset = NULL; + + array[count] = current->return_address; + + /* Check if the symbol is the signal trampoline and get the interrupted + * symbol address from the trampoline saved area. */ + if (is_sigtramp_address (current->return_address)) + { + struct signal_frame_32 *sigframe = + (struct signal_frame_32*) current; + gregset = &sigframe->mctx.gregs; + } + else if (is_sigtramp_address_rt (current->return_address)) + { + struct rt_signal_frame_32 *sigframe = + (struct rt_signal_frame_32*) current; + gregset = &sigframe->uc.uc_mcontext.uc_regs->gregs; + } + if (gregset) + { + array[++count] = (void*)((*gregset)[PT_NIP]); + current = (void*)((*gregset)[PT_R1]); + } + } + + /* It's possible the second-last stack frame can't return + (that is, it's __libc_start_main), in which case + the CRT startup code will have set its LR to 'NULL'. */ + if (count > 0 && array[count-1] == NULL) + count--; + + return count; +} +weak_alias (__backtrace, backtrace) +libc_hidden_def (__backtrace) -- cgit 1.4.1