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/**
* Copyright (C) ARM Limited 2010-2011. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
/*
* EABI backtrace stores {fp,lr} on the stack.
*/
struct frame_tail_eabi {
unsigned long fp; // points to prev_lr
unsigned long lr;
};
static void arm_backtrace_eabi(int cpu, int buftype, struct pt_regs * const regs, unsigned int depth)
{
#if defined(__arm__)
struct frame_tail_eabi *tail;
struct frame_tail_eabi *next;
struct frame_tail_eabi *ptrtail;
struct frame_tail_eabi buftail;
unsigned long fp = regs->ARM_fp;
unsigned long sp = regs->ARM_sp;
unsigned long lr = regs->ARM_lr;
int is_user_mode = user_mode(regs);
if (!is_user_mode) {
return;
}
/* entry preamble may not have executed */
gator_add_trace(cpu, buftype, lr);
/* check tail is valid */
if (fp == 0 || fp < sp) {
return;
}
tail = (struct frame_tail_eabi *)(fp - 4);
while (depth-- && tail && !((unsigned long) tail & 3)) {
/* Also check accessibility of one struct frame_tail beyond */
if (!access_ok(VERIFY_READ, tail, sizeof(struct frame_tail_eabi)))
return;
if (__copy_from_user_inatomic(&buftail, tail, sizeof(struct frame_tail_eabi)))
return;
ptrtail = &buftail;
lr = ptrtail[0].lr;
gator_add_trace(cpu, buftype, lr);
/* frame pointers should progress back up the stack, towards higher addresses */
next = (struct frame_tail_eabi *)(lr - 4);
if (tail >= next || lr == 0) {
fp = ptrtail[0].fp;
next = (struct frame_tail_eabi *)(fp - 4);
/* check tail is valid */
if (tail >= next || fp == 0) {
return;
}
}
tail = next;
}
#endif
}
#if defined(__arm__)
static DEFINE_PER_CPU(int, backtrace_buffer);
static int report_trace(struct stackframe *frame, void *d)
{
struct module *mod;
unsigned int *depth = d, addr = frame->pc, cookie = NO_COOKIE, cpu = smp_processor_id();
if (*depth) {
mod = __module_address(addr);
if (mod) {
cookie = get_cookie(cpu, per_cpu(backtrace_buffer, cpu), current, NULL, mod, true);
addr = addr - (unsigned long)mod->module_core;
}
gator_buffer_write_packed_int(cpu, per_cpu(backtrace_buffer, cpu), addr & ~1);
gator_buffer_write_packed_int(cpu, per_cpu(backtrace_buffer, cpu), cookie);
(*depth)--;
}
return *depth == 0;
}
#endif
// Uncomment the following line to enable kernel stack unwinding within gator, note it can also be defined from the Makefile
// #define GATOR_KERNEL_STACK_UNWINDING
static void kernel_backtrace(int cpu, int buftype, struct pt_regs * const regs)
{
#if defined(__arm__)
#ifdef GATOR_KERNEL_STACK_UNWINDING
int depth = gator_backtrace_depth;
#else
int depth = 1;
#endif
struct stackframe frame;
if (depth == 0)
depth = 1;
frame.fp = regs->ARM_fp;
frame.sp = regs->ARM_sp;
frame.lr = regs->ARM_lr;
frame.pc = regs->ARM_pc;
per_cpu(backtrace_buffer, cpu) = buftype;
walk_stackframe(&frame, report_trace, &depth);
#else
gator_buffer_write_packed_int(cpu, buftype, PC_REG & ~1);
gator_buffer_write_packed_int(cpu, buftype, NO_COOKIE);
#endif
}
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