cregit-Linux how code gets into the kernel

Release 4.14 arch/blackfin/kernel/dumpstack.c

/* Provide basic stack dumping functions
 *
 * Copyright 2004-2009 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later
 */

#include <linux/kernel.h>
#include <linux/thread_info.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/module.h>
#include <linux/sched/debug.h>

#include <asm/trace.h>

/*
 * Checks to see if the address pointed to is either a
 * 16-bit CALL instruction, or a 32-bit CALL instruction
 */

static bool is_bfin_call(unsigned short *addr) { unsigned int opcode; if (!get_instruction(&opcode, addr)) return false; if ((opcode >= 0x0060 && opcode <= 0x0067) || (opcode >= 0x0070 && opcode <= 0x0077) || (opcode >= 0xE3000000 && opcode <= 0xE3FFFFFF)) return true; return false; }

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void show_stack(struct task_struct *task, unsigned long *stack) { #ifdef CONFIG_PRINTK unsigned int *addr, *endstack, *fp = 0, *frame; unsigned short *ins_addr; char buf[150]; unsigned int i, j, ret_addr, frame_no = 0; /* * If we have been passed a specific stack, use that one otherwise * if we have been passed a task structure, use that, otherwise * use the stack of where the variable "stack" exists */ if (stack == NULL) { if (task) { /* We know this is a kernel stack, so this is the start/end */ stack = (unsigned long *)task->thread.ksp; endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE); } else { /* print out the existing stack info */ stack = (unsigned long *)&stack; endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack); } } else endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack); printk(KERN_NOTICE "Stack info:\n"); decode_address(buf, (unsigned int)stack); printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf); if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) { printk(KERN_NOTICE "Invalid stack pointer\n"); return; } /* First thing is to look for a frame pointer */ for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) { if (*addr & 0x1) continue; ins_addr = (unsigned short *)*addr; ins_addr--; if (is_bfin_call(ins_addr)) fp = addr - 1; if (fp) { /* Let's check to see if it is a frame pointer */ while (fp >= (addr - 1) && fp < endstack && fp && ((unsigned int) fp & 0x3) == 0) fp = (unsigned int *)*fp; if (fp == 0 || fp == endstack) { fp = addr - 1; break; } fp = 0; } } if (fp) { frame = fp; printk(KERN_NOTICE " FP: (0x%p)\n", fp); } else frame = 0; /* * Now that we think we know where things are, we * walk the stack again, this time printing things out * incase there is no frame pointer, we still look for * valid return addresses */ /* First time print out data, next time, print out symbols */ for (j = 0; j <= 1; j++) { if (j) printk(KERN_NOTICE "Return addresses in stack:\n"); else printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack); fp = frame; frame_no = 0; for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0; addr < endstack; addr++, i++) { ret_addr = 0; if (!j && i % 8 == 0) printk(KERN_NOTICE "%p:", addr); /* if it is an odd address, or zero, just skip it */ if (*addr & 0x1 || !*addr) goto print; ins_addr = (unsigned short *)*addr; /* Go back one instruction, and see if it is a CALL */ ins_addr--; ret_addr = is_bfin_call(ins_addr); print: if (!j && stack == (unsigned long *)addr) printk("[%08x]", *addr); else if (ret_addr) if (j) { decode_address(buf, (unsigned int)*addr); if (frame == addr) { printk(KERN_NOTICE " frame %2i : %s\n", frame_no, buf); continue; } printk(KERN_NOTICE " address : %s\n", buf); } else printk("<%08x>", *addr); else if (fp == addr) { if (j) frame = addr+1; else printk("(%08x)", *addr); fp = (unsigned int *)*addr; frame_no++; } else if (!j) printk(" %08x ", *addr); } if (!j) printk("\n"); } #endif }

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Robin Getz675100.00%1100.00%
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EXPORT_SYMBOL(show_stack);
void dump_stack(void) { unsigned long stack; #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON int tflags; #endif trace_buffer_save(tflags); dump_bfin_trace_buffer(); dump_stack_print_info(KERN_DEFAULT); show_stack(current, &stack); trace_buffer_restore(tflags); }

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Robin Getz4088.89%150.00%
Tejun Heo511.11%150.00%
Total45100.00%2100.00%

EXPORT_SYMBOL(dump_stack);

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Ingo Molnar30.37%125.00%
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