| /* libunwind - a platform-independent unwind library |
| Copyright (C) 2008 CodeSourcery |
| Copyright 2011 Linaro Limited |
| Copyright (C) 2012 Tommi Rantala <tt.rantala@gmail.com> |
| |
| This file is part of libunwind. |
| |
| Permission is hereby granted, free of charge, to any person obtaining |
| a copy of this software and associated documentation files (the |
| "Software"), to deal in the Software without restriction, including |
| without limitation the rights to use, copy, modify, merge, publish, |
| distribute, sublicense, and/or sell copies of the Software, and to |
| permit persons to whom the Software is furnished to do so, subject to |
| the following conditions: |
| |
| The above copyright notice and this permission notice shall be |
| included in all copies or substantial portions of the Software. |
| |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
| EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
| MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
| NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE |
| LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION |
| OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION |
| WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ |
| |
| #include "unwind_i.h" |
| #include "offsets.h" |
| #include "ex_tables.h" |
| |
| #include <signal.h> |
| |
| #define arm_exidx_step UNW_OBJ(arm_exidx_step) |
| |
| static inline int |
| arm_exidx_step (struct cursor *c) |
| { |
| uint8_t buf[32]; |
| int ret; |
| |
| /* mark PC unsaved */ |
| c->dwarf.loc[UNW_ARM_R15] = DWARF_NULL_LOC; |
| |
| if ((ret = tdep_find_proc_info (&c->dwarf, c->dwarf.ip, 1)) < 0) |
| return ret; |
| |
| if (c->dwarf.pi.format != UNW_INFO_FORMAT_ARM_EXIDX) |
| return -UNW_ENOINFO; |
| |
| ret = arm_exidx_extract (&c->dwarf, buf); |
| if (ret == -UNW_ESTOPUNWIND) |
| return 0; |
| else if (ret < 0) |
| return ret; |
| |
| ret = arm_exidx_decode (buf, ret, &c->dwarf); |
| if (ret < 0) |
| return ret; |
| |
| c->dwarf.pi_valid = 0; |
| |
| return (c->dwarf.ip == 0) ? 0 : 1; |
| } |
| |
| /* ANDROID support update. */ |
| |
| /* When taking a step back up the stack, the pc will point to the next |
| * instruction to execute, not the currently executing instruction. This |
| * function adjusts the pc to the currently executing instruction. |
| */ |
| static void adjust_ip(struct cursor *c) |
| { |
| unw_word_t ip, value; |
| ip = c->dwarf.ip; |
| |
| if (ip) |
| { |
| int adjust = 4; |
| if (ip & 1) |
| { |
| /* Thumb instructions, the currently executing instruction could be |
| * 2 or 4 bytes, so adjust appropriately. |
| */ |
| unw_addr_space_t as; |
| unw_accessors_t *a; |
| void *arg; |
| |
| as = c->dwarf.as; |
| a = unw_get_accessors (as); |
| arg = c->dwarf.as_arg; |
| |
| if (ip < 5 || (*a->access_mem) (as, ip-5, &value, 0, arg) < 0 || |
| (value & 0xe000f000) != 0xe000f000) |
| adjust = 2; |
| } |
| c->dwarf.ip -= adjust; |
| } |
| } |
| /* End of ANDROID update. */ |
| |
| PROTECTED int |
| unw_handle_signal_frame (unw_cursor_t *cursor) |
| { |
| struct cursor *c = (struct cursor *) cursor; |
| int ret; |
| unw_word_t sc_addr, sp, sp_addr = c->dwarf.cfa; |
| struct dwarf_loc sp_loc = DWARF_LOC (sp_addr, 0); |
| |
| if ((ret = dwarf_get (&c->dwarf, sp_loc, &sp)) < 0) |
| return -UNW_EUNSPEC; |
| |
| /* Obtain signal frame type (non-RT or RT). */ |
| ret = unw_is_signal_frame (cursor); |
| |
| /* Save the SP and PC to be able to return execution at this point |
| later in time (unw_resume). */ |
| c->sigcontext_sp = c->dwarf.cfa; |
| c->sigcontext_pc = c->dwarf.ip; |
| |
| /* Since kernel version 2.6.18 the non-RT signal frame starts with a |
| ucontext while the RT signal frame starts with a siginfo, followed |
| by a sigframe whose first element is an ucontext. |
| Prior 2.6.18 the non-RT signal frame starts with a sigcontext while |
| the RT signal frame starts with two pointers followed by a siginfo |
| and an ucontext. The first pointer points to the start of the siginfo |
| structure and the second one to the ucontext structure. */ |
| |
| if (ret == 1) |
| { |
| /* Handle non-RT signal frames. Check if the first word on the stack |
| is the magic number. */ |
| if (sp == 0x5ac3c35a) |
| { |
| c->sigcontext_format = ARM_SCF_LINUX_SIGFRAME; |
| sc_addr = sp_addr + LINUX_UC_MCONTEXT_OFF; |
| } |
| else |
| { |
| c->sigcontext_format = ARM_SCF_LINUX_OLD_SIGFRAME; |
| sc_addr = sp_addr; |
| } |
| } |
| else if (ret == 2) |
| { |
| /* Handle RT signal frames. Check if the first word on the stack is a |
| pointer to the siginfo structure. */ |
| if (sp == sp_addr + 8) |
| { |
| c->sigcontext_format = ARM_SCF_LINUX_OLD_RT_SIGFRAME; |
| sc_addr = sp_addr + 8 + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF; |
| } |
| else |
| { |
| c->sigcontext_format = ARM_SCF_LINUX_RT_SIGFRAME; |
| sc_addr = sp_addr + sizeof (siginfo_t) + LINUX_UC_MCONTEXT_OFF; |
| } |
| } |
| else |
| return -UNW_EUNSPEC; |
| |
| c->sigcontext_addr = sc_addr; |
| |
| /* Update the dwarf cursor. |
| Set the location of the registers to the corresponding addresses of the |
| uc_mcontext / sigcontext structure contents. */ |
| c->dwarf.loc[UNW_ARM_R0] = DWARF_LOC (sc_addr + LINUX_SC_R0_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R1] = DWARF_LOC (sc_addr + LINUX_SC_R1_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R2] = DWARF_LOC (sc_addr + LINUX_SC_R2_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R3] = DWARF_LOC (sc_addr + LINUX_SC_R3_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R4] = DWARF_LOC (sc_addr + LINUX_SC_R4_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R5] = DWARF_LOC (sc_addr + LINUX_SC_R5_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R6] = DWARF_LOC (sc_addr + LINUX_SC_R6_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R7] = DWARF_LOC (sc_addr + LINUX_SC_R7_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R8] = DWARF_LOC (sc_addr + LINUX_SC_R8_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R9] = DWARF_LOC (sc_addr + LINUX_SC_R9_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R10] = DWARF_LOC (sc_addr + LINUX_SC_R10_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R11] = DWARF_LOC (sc_addr + LINUX_SC_FP_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R12] = DWARF_LOC (sc_addr + LINUX_SC_IP_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R13] = DWARF_LOC (sc_addr + LINUX_SC_SP_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R14] = DWARF_LOC (sc_addr + LINUX_SC_LR_OFF, 0); |
| c->dwarf.loc[UNW_ARM_R15] = DWARF_LOC (sc_addr + LINUX_SC_PC_OFF, 0); |
| |
| /* Set SP/CFA and PC/IP. */ |
| dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R13], &c->dwarf.cfa); |
| dwarf_get (&c->dwarf, c->dwarf.loc[UNW_ARM_R15], &c->dwarf.ip); |
| |
| c->dwarf.pi_valid = 0; |
| |
| return 1; |
| } |
| |
| PROTECTED int |
| unw_step (unw_cursor_t *cursor) |
| { |
| struct cursor *c = (struct cursor *) cursor; |
| int ret = -UNW_EUNSPEC; |
| |
| Debug (1, "(cursor=%p)\n", c); |
| |
| unw_word_t old_ip = c->dwarf.ip; |
| unw_word_t old_cfa = c->dwarf.cfa; |
| |
| /* Check if this is a signal frame. */ |
| if (unw_is_signal_frame (cursor)) |
| { |
| ret = unw_handle_signal_frame (cursor); |
| } |
| |
| #ifdef CONFIG_DEBUG_FRAME |
| /* First, try DWARF-based unwinding. */ |
| if (ret < 0 && UNW_TRY_METHOD(UNW_ARM_METHOD_DWARF)) |
| { |
| ret = dwarf_step (&c->dwarf); |
| Debug(1, "dwarf_step()=%d\n", ret); |
| |
| if (likely (ret > 0)) |
| ret = 1; |
| else if (unlikely (ret == -UNW_ESTOPUNWIND)) |
| ret = 0; |
| } |
| #endif /* CONFIG_DEBUG_FRAME */ |
| |
| /* Next, try extbl-based unwinding. */ |
| if (ret < 0 && UNW_TRY_METHOD (UNW_ARM_METHOD_EXIDX)) |
| { |
| ret = arm_exidx_step (c); |
| if (ret > 0) |
| ret = 1; |
| if (ret == -UNW_ESTOPUNWIND || ret == 0) |
| ret = 0; |
| } |
| |
| /* Fall back on APCS frame parsing. |
| Note: This won't work in case the ARM EABI is used. */ |
| if (unlikely (ret < 0)) |
| { |
| if (UNW_TRY_METHOD(UNW_ARM_METHOD_FRAME)) |
| { |
| ret = UNW_ESUCCESS; |
| /* DWARF unwinding failed, try to follow APCS/optimized APCS frame chain */ |
| unw_word_t instr, i; |
| Debug (13, "dwarf_step() failed (ret=%d), trying frame-chain\n", ret); |
| dwarf_loc_t ip_loc, fp_loc; |
| unw_word_t frame; |
| /* Mark all registers unsaved, since we don't know where |
| they are saved (if at all), except for the EBP and |
| EIP. */ |
| if (dwarf_get(&c->dwarf, c->dwarf.loc[UNW_ARM_R11], &frame) < 0) |
| { |
| return 0; |
| } |
| for (i = 0; i < DWARF_NUM_PRESERVED_REGS; ++i) { |
| c->dwarf.loc[i] = DWARF_NULL_LOC; |
| } |
| if (frame) |
| { |
| if (dwarf_get(&c->dwarf, DWARF_LOC(frame, 0), &instr) < 0) |
| { |
| return 0; |
| } |
| instr -= 8; |
| if (dwarf_get(&c->dwarf, DWARF_LOC(instr, 0), &instr) < 0) |
| { |
| return 0; |
| } |
| if ((instr & 0xFFFFD800) == 0xE92DD800) |
| { |
| /* Standard APCS frame. */ |
| ip_loc = DWARF_LOC(frame - 4, 0); |
| fp_loc = DWARF_LOC(frame - 12, 0); |
| } |
| else |
| { |
| /* Codesourcery optimized normal frame. */ |
| ip_loc = DWARF_LOC(frame, 0); |
| fp_loc = DWARF_LOC(frame - 4, 0); |
| } |
| if (dwarf_get(&c->dwarf, ip_loc, &c->dwarf.ip) < 0) |
| { |
| return 0; |
| } |
| c->dwarf.loc[UNW_ARM_R12] = ip_loc; |
| c->dwarf.loc[UNW_ARM_R11] = fp_loc; |
| c->dwarf.pi_valid = 0; |
| Debug(15, "ip=%x\n", c->dwarf.ip); |
| } |
| else |
| { |
| ret = -UNW_ENOINFO; |
| } |
| } |
| } |
| |
| /* ANDROID support update. */ |
| if (ret < 0 && UNW_TRY_METHOD(UNW_ARM_METHOD_LR) && c->dwarf.frame == 0) |
| { |
| /* If this is the first frame, the code may be executing garbage |
| * in the middle of nowhere. In this case, try using the lr as |
| * the pc. |
| */ |
| unw_word_t lr; |
| if (dwarf_get(&c->dwarf, c->dwarf.loc[UNW_ARM_R14], &lr) >= 0) |
| { |
| if (lr != c->dwarf.ip) |
| { |
| ret = 1; |
| c->dwarf.ip = lr; |
| } |
| } |
| } |
| /* End of ANDROID update. */ |
| |
| if (ret >= 0) |
| { |
| adjust_ip(c); |
| if (c->dwarf.ip == old_ip && c->dwarf.cfa == old_cfa) |
| { |
| Dprintf ("%s: ip and cfa unchanged; stopping here (ip=0x%lx)\n", |
| __FUNCTION__, (long) c->dwarf.ip); |
| return -UNW_EBADFRAME; |
| } |
| c->dwarf.frame++; |
| } |
| return ret == -UNW_ENOINFO ? 0 : ret; |
| } |
