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rt-thread/libcpu/arm/cortex-a/backtrace.c

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/*
* Copyright (c) 2006-2022, RT-Thread Development Team
*
* SPDX-License-Identifier: Apache-2.0
*
* Change Logs:
* Date Author Notes
* 2019-03-29 Jesven the first version
*/
#ifndef __CHECKER__
#if !defined (__ARM_EABI__)
#warning Your compiler does not have EABI support.
#warning ARM unwind is known to compile only with EABI compilers.
#warning Change compiler or disable ARM_UNWIND option.
#elif (__GNUC__ == 4 && __GNUC_MINOR__ <= 2) && !defined(__clang__)
#warning Your compiler is too buggy; it is known to not compile ARM unwind support.
#warning Change compiler or disable ARM_UNWIND option.
#endif
#endif /* __CHECKER__ */
#include <rtthread.h>
#include <rthw.h>
#include <backtrace.h>
#define DBG_TAG "BACKTRACE"
#define DBG_LVL DBG_INFO
#include <rtdbg.h>
#ifdef RT_USING_SMART
#include <lwp.h>
#include <lwp_user_mm.h>
#include <lwp_arch.h>
#endif
rt_inline void arm_get_current_stackframe(struct pt_regs *regs, struct stackframe *frame)
{
frame->fp = frame_pointer(regs);
frame->sp = regs->ARM_sp;
frame->lr = regs->ARM_lr;
frame->pc = regs->ARM_pc;
}
struct unwind_ctrl_block {
unsigned long vrs[16]; /* virtual register set */
const unsigned long *insn; /* pointer to the current instructions word */
unsigned long sp_high; /* highest value of sp allowed */
/*
* 1 : check for stack overflow for each register pop.
* 0 : save overhead if there is plenty of stack remaining.
*/
int check_each_pop;
int entries; /* number of entries left to interpret */
int byte; /* current byte number in the instructions word */
};
enum regs
{
#ifdef CONFIG_THUMB2_KERNEL
FP = 7,
#else
FP = 11,
#endif
SP = 13,
LR = 14,
PC = 15
};
static int core_kernel_text(unsigned long addr)
{
return 1;
}
/* Convert a prel31 symbol to an absolute address */
#define prel31_to_addr(ptr) \
({ \
/* sign-extend to 32 bits */ \
long offset = (((long)*(ptr)) << 1) >> 1; \
(unsigned long)(ptr) + offset; \
})
/*
* Binary search in the unwind index. The entries are
* guaranteed to be sorted in ascending order by the linker.
*
* start = first entry
* origin = first entry with positive offset (or stop if there is no such entry)
* stop - 1 = last entry
*/
static const struct unwind_idx *search_index(unsigned long addr,
const struct unwind_idx *start,
const struct unwind_idx *origin,
const struct unwind_idx *stop)
{
unsigned long addr_prel31;
LOG_D("%s(%08lx, %x, %x, %x)",
__func__, addr, start, origin, stop);
/*
* only search in the section with the matching sign. This way the
* prel31 numbers can be compared as unsigned longs.
*/
if (addr < (unsigned long)start)
/* negative offsets: [start; origin) */
stop = origin;
else
/* positive offsets: [origin; stop) */
start = origin;
/* prel31 for address relavive to start */
addr_prel31 = (addr - (unsigned long)start) & 0x7fffffff;
while (start < stop - 1)
{
const struct unwind_idx *mid = start + ((stop - start) >> 1);
/*
* As addr_prel31 is relative to start an offset is needed to
* make it relative to mid.
*/
if (addr_prel31 - ((unsigned long)mid - (unsigned long)start) <
mid->addr_offset)
stop = mid;
else
{
/* keep addr_prel31 relative to start */
addr_prel31 -= ((unsigned long)mid -
(unsigned long)start);
start = mid;
}
}
if (start->addr_offset <= addr_prel31)
return start;
else
{
LOG_W("unwind: Unknown symbol address %08lx", addr);
return RT_NULL;
}
}
static const struct unwind_idx *unwind_find_origin(
const struct unwind_idx *start, const struct unwind_idx *stop)
{
LOG_D("%s(%x, %x)", __func__, start, stop);
while (start < stop)
{
const struct unwind_idx *mid = start + ((stop - start) >> 1);
if (mid->addr_offset >= 0x40000000)
/* negative offset */
start = mid + 1;
else
/* positive offset */
stop = mid;
}
LOG_D("%s -> %x", __func__, stop);
return stop;
}
static const struct unwind_idx *unwind_find_idx(unsigned long addr, const struct unwind_idx **origin_idx, const struct unwind_idx exidx_start[], const struct unwind_idx exidx_end[])
{
const struct unwind_idx *idx = RT_NULL;
LOG_D("%s(%08lx)", __func__, addr);
if (core_kernel_text(addr))
{
if (!*origin_idx)
*origin_idx =
unwind_find_origin(exidx_start,
exidx_end);
/* main unwind table */
idx = search_index(addr, exidx_start,
*origin_idx,
exidx_end);
}
LOG_D("%s: idx = %x", __func__, idx);
return idx;
}
static unsigned long unwind_get_byte(struct unwind_ctrl_block *ctrl)
{
unsigned long ret;
if (ctrl->entries <= 0)
{
LOG_W("unwind: Corrupt unwind table");
return 0;
}
ret = (*ctrl->insn >> (ctrl->byte * 8)) & 0xff;
if (ctrl->byte == 0)
{
ctrl->insn++;
ctrl->entries--;
ctrl->byte = 3;
}
else
ctrl->byte--;
return ret;
}
/* Before poping a register check whether it is feasible or not */
static int unwind_pop_register(struct unwind_ctrl_block *ctrl,
unsigned long **vsp, unsigned int reg)
{
if (ctrl->check_each_pop)
if (*vsp >= (unsigned long *)ctrl->sp_high)
return -URC_FAILURE;
ctrl->vrs[reg] = *(*vsp)++;
return URC_OK;
}
/* Helper functions to execute the instructions */
static int unwind_exec_pop_subset_r4_to_r13(struct unwind_ctrl_block *ctrl,
unsigned long mask)
{
unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
int load_sp, reg = 4;
load_sp = mask & (1 << (13 - 4));
while (mask)
{
if (mask & 1)
if (unwind_pop_register(ctrl, &vsp, reg))
return -URC_FAILURE;
mask >>= 1;
reg++;
}
if (!load_sp)
ctrl->vrs[SP] = (unsigned long)vsp;
return URC_OK;
}
static int unwind_exec_pop_r4_to_rN(struct unwind_ctrl_block *ctrl,
unsigned long insn)
{
unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
int reg;
/* pop R4-R[4+bbb] */
for (reg = 4; reg <= 4 + (insn & 7); reg++)
if (unwind_pop_register(ctrl, &vsp, reg))
return -URC_FAILURE;
if (insn & 0x8)
if (unwind_pop_register(ctrl, &vsp, 14))
return -URC_FAILURE;
ctrl->vrs[SP] = (unsigned long)vsp;
return URC_OK;
}
static int unwind_exec_pop_subset_r0_to_r3(struct unwind_ctrl_block *ctrl,
unsigned long mask)
{
unsigned long *vsp = (unsigned long *)ctrl->vrs[SP];
int reg = 0;
/* pop R0-R3 according to mask */
while (mask)
{
if (mask & 1)
if (unwind_pop_register(ctrl, &vsp, reg))
return -URC_FAILURE;
mask >>= 1;
reg++;
}
ctrl->vrs[SP] = (unsigned long)vsp;
return URC_OK;
}
/*
* Execute the current unwind instruction.
*/
static int unwind_exec_insn(struct unwind_ctrl_block *ctrl)
{
unsigned long insn = unwind_get_byte(ctrl);
int ret = URC_OK;
LOG_D("%s: insn = %08lx", __func__, insn);
if ((insn & 0xc0) == 0x00)
ctrl->vrs[SP] += ((insn & 0x3f) << 2) + 4;
else if ((insn & 0xc0) == 0x40)
ctrl->vrs[SP] -= ((insn & 0x3f) << 2) + 4;
else if ((insn & 0xf0) == 0x80)
{
unsigned long mask;
insn = (insn << 8) | unwind_get_byte(ctrl);
mask = insn & 0x0fff;
if (mask == 0)
{
LOG_W("unwind: 'Refuse to unwind' instruction %04lx",
insn);
return -URC_FAILURE;
}
ret = unwind_exec_pop_subset_r4_to_r13(ctrl, mask);
if (ret)
goto error;
}
else if ((insn & 0xf0) == 0x90 &&
(insn & 0x0d) != 0x0d)
ctrl->vrs[SP] = ctrl->vrs[insn & 0x0f];
else if ((insn & 0xf0) == 0xa0)
{
ret = unwind_exec_pop_r4_to_rN(ctrl, insn);
if (ret)
goto error;
}
else if (insn == 0xb0)
{
if (ctrl->vrs[PC] == 0)
ctrl->vrs[PC] = ctrl->vrs[LR];
/* no further processing */
ctrl->entries = 0;
}
else if (insn == 0xb1)
{
unsigned long mask = unwind_get_byte(ctrl);
if (mask == 0 || mask & 0xf0)
{
LOG_W("unwind: Spare encoding %04lx",
(insn << 8) | mask);
return -URC_FAILURE;
}
ret = unwind_exec_pop_subset_r0_to_r3(ctrl, mask);
if (ret)
goto error;
}
else if (insn == 0xb2)
{
unsigned long uleb128 = unwind_get_byte(ctrl);
ctrl->vrs[SP] += 0x204 + (uleb128 << 2);
}
else
{
LOG_W("unwind: Unhandled instruction %02lx", insn);
return -URC_FAILURE;
}
LOG_D("%s: fp = %08lx sp = %08lx lr = %08lx pc = %08lx", __func__,
ctrl->vrs[FP], ctrl->vrs[SP], ctrl->vrs[LR], ctrl->vrs[PC]);
error:
return ret;
}
#ifdef RT_BACKTRACE_FUNCTION_NAME
static char *unwind_get_function_name(void *address)
{
uint32_t flag_word = *(uint32_t *)((char*)address - 4);
if ((flag_word & 0xff000000) == 0xff000000)
{
return (char *)((char*)address - 4 - (flag_word & 0x00ffffff));
}
return RT_NULL;
}
#endif
/*
* Unwind a single frame starting with *sp for the symbol at *pc. It
* updates the *pc and *sp with the new values.
*/
int unwind_frame(struct stackframe *frame, const struct unwind_idx **origin_idx, const struct unwind_idx exidx_start[], const struct unwind_idx exidx_end[])
{
unsigned long low;
const struct unwind_idx *idx;
struct unwind_ctrl_block ctrl;
struct rt_thread *rt_c_thread;
/* store the highest address on the stack to avoid crossing it*/
low = frame->sp;
rt_c_thread = rt_thread_self();
ctrl.sp_high = (unsigned long)((char*)rt_c_thread->stack_addr + rt_c_thread->stack_size);
LOG_D("%s(pc = %08lx lr = %08lx sp = %08lx)", __func__,
frame->pc, frame->lr, frame->sp);
idx = unwind_find_idx(frame->pc, origin_idx, exidx_start, exidx_end);
if (!idx)
{
LOG_W("unwind: Index not found %08lx", frame->pc);
return -URC_FAILURE;
}
#ifdef RT_BACKTRACE_FUNCTION_NAME
{
char *fun_name;
fun_name = unwind_get_function_name((void *)prel31_to_addr(&idx->addr_offset));
if (fun_name)
{
rt_kprintf("0x%08x @ %s\n", frame->pc, fun_name);
}
}
#endif
ctrl.vrs[FP] = frame->fp;
ctrl.vrs[SP] = frame->sp;
ctrl.vrs[LR] = frame->lr;
ctrl.vrs[PC] = 0;
if (idx->insn == 1)
/* can't unwind */
return -URC_FAILURE;
else if ((idx->insn & 0x80000000) == 0)
/* prel31 to the unwind table */
ctrl.insn = (unsigned long *)prel31_to_addr(&idx->insn);
else if ((idx->insn & 0xff000000) == 0x80000000)
/* only personality routine 0 supported in the index */
ctrl.insn = &idx->insn;
else
{
LOG_W("unwind: Unsupported personality routine %08lx in the index at %x",
idx->insn, idx);
return -URC_FAILURE;
}
/* check the personality routine */
if ((*ctrl.insn & 0xff000000) == 0x80000000)
{
ctrl.byte = 2;
ctrl.entries = 1;
}
else if ((*ctrl.insn & 0xff000000) == 0x81000000)
{
ctrl.byte = 1;
ctrl.entries = 1 + ((*ctrl.insn & 0x00ff0000) >> 16);
}
else
{
LOG_W("unwind: Unsupported personality routine %08lx at %x",
*ctrl.insn, ctrl.insn);
return -URC_FAILURE;
}
ctrl.check_each_pop = 0;
while (ctrl.entries > 0)
{
int urc;
if ((ctrl.sp_high - ctrl.vrs[SP]) < sizeof(ctrl.vrs))
ctrl.check_each_pop = 1;
urc = unwind_exec_insn(&ctrl);
if (urc < 0)
return urc;
if (ctrl.vrs[SP] < low || ctrl.vrs[SP] >= ctrl.sp_high)
return -URC_FAILURE;
}
if (ctrl.vrs[PC] == 0)
ctrl.vrs[PC] = ctrl.vrs[LR];
/* check for infinite loop */
if (frame->pc == ctrl.vrs[PC])
return -URC_FAILURE;
frame->fp = ctrl.vrs[FP];
frame->sp = ctrl.vrs[SP];
frame->lr = ctrl.vrs[LR];
frame->pc = ctrl.vrs[PC];
return URC_OK;
}
void unwind_backtrace(struct pt_regs *regs, const struct unwind_idx exidx_start[], const struct unwind_idx exidx_end[])
{
struct stackframe frame;
const struct unwind_idx *origin_idx = RT_NULL;
LOG_D("%s(regs = %x)", __func__, regs);
arm_get_current_stackframe(regs, &frame);
#ifndef RT_BACKTRACE_FUNCTION_NAME
rt_kprintf("please use: addr2line -e rtthread.elf -a -f %08x", frame.pc);
#endif
LOG_D("pc = %08x, sp = %08x", frame.pc, frame.sp);
while (1)
{
int urc;
urc = unwind_frame(&frame, &origin_idx, exidx_start, exidx_end);
if (urc < 0)
break;
//dump_backtrace_entry(where, frame.pc, frame.sp - 4);
#ifndef RT_BACKTRACE_FUNCTION_NAME
rt_kprintf(" %08x", frame.pc);
#endif
LOG_D("from: pc = %08x, frame = %08x", frame.pc, frame.sp - 4);
}
rt_kprintf("\n");
}
extern const struct unwind_idx __exidx_start[];
extern const struct unwind_idx __exidx_end[];
void rt_unwind(struct rt_hw_exp_stack *regs, unsigned int pc_adj)
{
struct pt_regs e_regs;
e_regs.ARM_fp = regs->fp;
e_regs.ARM_sp = regs->sp;
e_regs.ARM_lr = regs->lr;
e_regs.ARM_pc = regs->pc - pc_adj;
#ifdef RT_USING_SMART
if (!lwp_user_accessable((void *)e_regs.ARM_pc, sizeof (void *)))
{
e_regs.ARM_pc = regs->lr - sizeof(void *);
}
#endif
rt_kprintf("backtrace:\n");
unwind_backtrace(&e_regs, __exidx_start, __exidx_end);
}
rt_err_t rt_backtrace(void)
{
struct rt_hw_exp_stack regs;
asm volatile ("mov %0, fp":"=r"(regs.fp));
asm volatile ("mov %0, sp":"=r"(regs.sp));
asm volatile ("mov %0, lr":"=r"(regs.lr));
asm volatile ("mov %0, pc":"=r"(regs.pc));
rt_unwind(&regs, 8);
return RT_EOK;
}
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