The i386 thread_info contains a previous_esp field that is used to daisy chain the different stacks for dump_stack() (ie. irq, softirq, thread stacks). The goal is to eventual make i386 handling of thread_info the same as x86_64, which means that the thread_info will not be in the stack but as a per_cpu variable. We will no longer depend on thread_info being able to daisy chain different stacks as it will only exist in one location (the thread stack). By moving previous_esp to the end of thread_info and referencing it as an offset instead of using a thread_info field, this becomes a stepping stone to moving the thread_info. The offset to get to the previous stack is rather ugly in this patch, but this is only temporary and the prev_esp will be changed in the next commit. This commit is more for sanity checks of the change. Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Robert Richter <rric@kernel.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20110806012353.891757693@goodmis.org Link: http://lkml.kernel.org/r/20140206144321.608754481@goodmis.org Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
147 lines
3 KiB
C
147 lines
3 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#include <linux/kallsyms.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kdebug.h>
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#include <linux/module.h>
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#include <linux/ptrace.h>
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#include <linux/kexec.h>
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#include <linux/sysfs.h>
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#include <linux/bug.h>
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#include <linux/nmi.h>
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#include <asm/stacktrace.h>
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void dump_trace(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, unsigned long bp,
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const struct stacktrace_ops *ops, void *data)
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{
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int graph = 0;
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u32 *prev_esp;
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if (!task)
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task = current;
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if (!stack) {
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unsigned long dummy;
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stack = &dummy;
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if (task && task != current)
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stack = (unsigned long *)task->thread.sp;
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}
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if (!bp)
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bp = stack_frame(task, regs);
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for (;;) {
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struct thread_info *context;
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context = (struct thread_info *)
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((unsigned long)stack & (~(THREAD_SIZE - 1)));
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bp = ops->walk_stack(context, stack, bp, ops, data, NULL, &graph);
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/* Stop if not on irq stack */
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if (task_stack_page(task) == context)
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break;
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/* The previous esp is just above the context */
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prev_esp = (u32 *) ((char *)context + sizeof(struct thread_info) -
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sizeof(long));
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stack = (unsigned long *)*prev_esp;
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if (!stack)
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break;
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if (ops->stack(data, "IRQ") < 0)
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break;
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touch_nmi_watchdog();
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}
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}
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EXPORT_SYMBOL(dump_trace);
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void
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show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *sp, unsigned long bp, char *log_lvl)
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{
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unsigned long *stack;
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int i;
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if (sp == NULL) {
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if (task)
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sp = (unsigned long *)task->thread.sp;
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else
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sp = (unsigned long *)&sp;
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}
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stack = sp;
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for (i = 0; i < kstack_depth_to_print; i++) {
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if (kstack_end(stack))
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break;
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if (i && ((i % STACKSLOTS_PER_LINE) == 0))
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pr_cont("\n");
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pr_cont(" %08lx", *stack++);
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touch_nmi_watchdog();
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}
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pr_cont("\n");
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show_trace_log_lvl(task, regs, sp, bp, log_lvl);
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}
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void show_regs(struct pt_regs *regs)
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{
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int i;
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show_regs_print_info(KERN_EMERG);
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__show_regs(regs, !user_mode_vm(regs));
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/*
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* When in-kernel, we also print out the stack and code at the
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* time of the fault..
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*/
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if (!user_mode_vm(regs)) {
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unsigned int code_prologue = code_bytes * 43 / 64;
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unsigned int code_len = code_bytes;
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unsigned char c;
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u8 *ip;
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pr_emerg("Stack:\n");
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show_stack_log_lvl(NULL, regs, ®s->sp, 0, KERN_EMERG);
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pr_emerg("Code:");
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ip = (u8 *)regs->ip - code_prologue;
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if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
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/* try starting at IP */
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ip = (u8 *)regs->ip;
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code_len = code_len - code_prologue + 1;
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}
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for (i = 0; i < code_len; i++, ip++) {
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if (ip < (u8 *)PAGE_OFFSET ||
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probe_kernel_address(ip, c)) {
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pr_cont(" Bad EIP value.");
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break;
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}
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if (ip == (u8 *)regs->ip)
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pr_cont(" <%02x>", c);
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else
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pr_cont(" %02x", c);
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}
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}
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pr_cont("\n");
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}
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int is_valid_bugaddr(unsigned long ip)
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{
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unsigned short ud2;
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if (ip < PAGE_OFFSET)
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return 0;
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if (probe_kernel_address((unsigned short *)ip, ud2))
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return 0;
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return ud2 == 0x0b0f;
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}
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