498 lines
14 KiB
C
498 lines
14 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/kprobes.h>
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#include <linux/module.h>
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#include <linux/pfn.h>
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#include <linux/kallsyms.h>
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#include <linux/stacktrace.h>
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#include <linux/uaccess.h>
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#include <linux/mmzone.h>
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#include <asm/backtrace.h>
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#include <asm/page.h>
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#include <asm/tlbflush.h>
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#include <asm/ucontext.h>
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#include <asm/sigframe.h>
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#include <asm/stack.h>
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#include <arch/abi.h>
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#include <arch/interrupts.h>
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#define KBT_ONGOING 0 /* Backtrace still ongoing */
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#define KBT_DONE 1 /* Backtrace cleanly completed */
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#define KBT_RUNNING 2 /* Can't run backtrace on a running task */
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#define KBT_LOOP 3 /* Backtrace entered a loop */
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/* Is address on the specified kernel stack? */
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static int in_kernel_stack(struct KBacktraceIterator *kbt, unsigned long sp)
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{
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ulong kstack_base = (ulong) kbt->task->stack;
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if (kstack_base == 0) /* corrupt task pointer; just follow stack... */
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return sp >= PAGE_OFFSET && sp < (unsigned long)high_memory;
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return sp >= kstack_base && sp < kstack_base + THREAD_SIZE;
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}
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/* Is address valid for reading? */
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static int valid_address(struct KBacktraceIterator *kbt, unsigned long address)
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{
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HV_PTE *l1_pgtable = kbt->pgtable;
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HV_PTE *l2_pgtable;
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unsigned long pfn;
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HV_PTE pte;
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struct page *page;
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if (l1_pgtable == NULL)
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return 0; /* can't read user space in other tasks */
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#ifdef CONFIG_64BIT
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/* Find the real l1_pgtable by looking in the l0_pgtable. */
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pte = l1_pgtable[HV_L0_INDEX(address)];
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if (!hv_pte_get_present(pte))
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return 0;
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pfn = hv_pte_get_pfn(pte);
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if (pte_huge(pte)) {
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if (!pfn_valid(pfn)) {
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pr_err("L0 huge page has bad pfn %#lx\n", pfn);
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return 0;
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}
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return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
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}
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page = pfn_to_page(pfn);
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BUG_ON(PageHighMem(page)); /* No HIGHMEM on 64-bit. */
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l1_pgtable = (HV_PTE *)pfn_to_kaddr(pfn);
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#endif
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pte = l1_pgtable[HV_L1_INDEX(address)];
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if (!hv_pte_get_present(pte))
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return 0;
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pfn = hv_pte_get_pfn(pte);
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if (pte_huge(pte)) {
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if (!pfn_valid(pfn)) {
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pr_err("huge page has bad pfn %#lx\n", pfn);
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return 0;
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}
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return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
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}
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page = pfn_to_page(pfn);
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if (PageHighMem(page)) {
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pr_err("L2 page table not in LOWMEM (%#llx)\n",
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HV_PFN_TO_CPA(pfn));
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return 0;
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}
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l2_pgtable = (HV_PTE *)pfn_to_kaddr(pfn);
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pte = l2_pgtable[HV_L2_INDEX(address)];
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return hv_pte_get_present(pte) && hv_pte_get_readable(pte);
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}
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/* Callback for backtracer; basically a glorified memcpy */
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static bool read_memory_func(void *result, unsigned long address,
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unsigned int size, void *vkbt)
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{
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int retval;
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struct KBacktraceIterator *kbt = (struct KBacktraceIterator *)vkbt;
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if (__kernel_text_address(address)) {
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/* OK to read kernel code. */
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} else if (address >= PAGE_OFFSET) {
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/* We only tolerate kernel-space reads of this task's stack */
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if (!in_kernel_stack(kbt, address))
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return 0;
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} else if (!valid_address(kbt, address)) {
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return 0; /* invalid user-space address */
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}
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pagefault_disable();
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retval = __copy_from_user_inatomic(result,
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(void __user __force *)address,
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size);
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pagefault_enable();
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return (retval == 0);
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}
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/* Return a pt_regs pointer for a valid fault handler frame */
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static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
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{
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const char *fault = NULL; /* happy compiler */
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char fault_buf[64];
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unsigned long sp = kbt->it.sp;
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struct pt_regs *p;
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if (!in_kernel_stack(kbt, sp))
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return NULL;
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if (!in_kernel_stack(kbt, sp + C_ABI_SAVE_AREA_SIZE + PTREGS_SIZE-1))
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return NULL;
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p = (struct pt_regs *)(sp + C_ABI_SAVE_AREA_SIZE);
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if (p->faultnum == INT_SWINT_1 || p->faultnum == INT_SWINT_1_SIGRETURN)
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fault = "syscall";
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else {
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if (kbt->verbose) { /* else we aren't going to use it */
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snprintf(fault_buf, sizeof(fault_buf),
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"interrupt %ld", p->faultnum);
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fault = fault_buf;
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}
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}
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if (EX1_PL(p->ex1) == KERNEL_PL &&
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__kernel_text_address(p->pc) &&
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in_kernel_stack(kbt, p->sp) &&
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p->sp >= sp) {
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if (kbt->verbose)
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pr_err(" <%s while in kernel mode>\n", fault);
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} else if (EX1_PL(p->ex1) == USER_PL &&
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p->pc < PAGE_OFFSET &&
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p->sp < PAGE_OFFSET) {
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if (kbt->verbose)
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pr_err(" <%s while in user mode>\n", fault);
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} else if (kbt->verbose) {
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pr_err(" (odd fault: pc %#lx, sp %#lx, ex1 %#lx?)\n",
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p->pc, p->sp, p->ex1);
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p = NULL;
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}
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if (!kbt->profile || (INT_MASK(p->faultnum) & QUEUED_INTERRUPTS) == 0)
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return p;
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return NULL;
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}
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/* Is the pc pointing to a sigreturn trampoline? */
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static int is_sigreturn(unsigned long pc)
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{
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return (pc == VDSO_BASE);
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}
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/* Return a pt_regs pointer for a valid signal handler frame */
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static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt)
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{
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BacktraceIterator *b = &kbt->it;
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if (b->pc == VDSO_BASE) {
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struct rt_sigframe *frame;
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unsigned long sigframe_top =
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b->sp + sizeof(struct rt_sigframe) - 1;
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if (!valid_address(kbt, b->sp) ||
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!valid_address(kbt, sigframe_top)) {
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if (kbt->verbose)
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pr_err(" (odd signal: sp %#lx?)\n",
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(unsigned long)(b->sp));
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return NULL;
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}
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frame = (struct rt_sigframe *)b->sp;
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if (kbt->verbose) {
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pr_err(" <received signal %d>\n",
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frame->info.si_signo);
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}
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return (struct pt_regs *)&frame->uc.uc_mcontext;
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}
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return NULL;
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}
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static int KBacktraceIterator_is_sigreturn(struct KBacktraceIterator *kbt)
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{
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return is_sigreturn(kbt->it.pc);
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}
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static int KBacktraceIterator_restart(struct KBacktraceIterator *kbt)
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{
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struct pt_regs *p;
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p = valid_fault_handler(kbt);
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if (p == NULL)
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p = valid_sigframe(kbt);
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if (p == NULL)
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return 0;
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backtrace_init(&kbt->it, read_memory_func, kbt,
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p->pc, p->lr, p->sp, p->regs[52]);
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kbt->new_context = 1;
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return 1;
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}
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/* Find a frame that isn't a sigreturn, if there is one. */
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static int KBacktraceIterator_next_item_inclusive(
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struct KBacktraceIterator *kbt)
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{
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for (;;) {
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do {
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if (!KBacktraceIterator_is_sigreturn(kbt))
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return KBT_ONGOING;
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} while (backtrace_next(&kbt->it));
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if (!KBacktraceIterator_restart(kbt))
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return KBT_DONE;
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}
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}
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/*
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* If the current sp is on a page different than what we recorded
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* as the top-of-kernel-stack last time we context switched, we have
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* probably blown the stack, and nothing is going to work out well.
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* If we can at least get out a warning, that may help the debug,
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* though we probably won't be able to backtrace into the code that
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* actually did the recursive damage.
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*/
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static void validate_stack(struct pt_regs *regs)
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{
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int cpu = smp_processor_id();
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unsigned long ksp0 = get_current_ksp0();
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unsigned long ksp0_base = ksp0 - THREAD_SIZE;
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unsigned long sp = stack_pointer;
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if (EX1_PL(regs->ex1) == KERNEL_PL && regs->sp >= ksp0) {
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pr_err("WARNING: cpu %d: kernel stack page %#lx underrun!\n"
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" sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
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cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
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}
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else if (sp < ksp0_base + sizeof(struct thread_info)) {
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pr_err("WARNING: cpu %d: kernel stack page %#lx overrun!\n"
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" sp %#lx (%#lx in caller), caller pc %#lx, lr %#lx\n",
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cpu, ksp0_base, sp, regs->sp, regs->pc, regs->lr);
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}
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}
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void KBacktraceIterator_init(struct KBacktraceIterator *kbt,
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struct task_struct *t, struct pt_regs *regs)
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{
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unsigned long pc, lr, sp, r52;
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int is_current;
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/*
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* Set up callback information. We grab the kernel stack base
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* so we will allow reads of that address range, and if we're
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* asking about the current process we grab the page table
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* so we can check user accesses before trying to read them.
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* We flush the TLB to avoid any weird skew issues.
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*/
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is_current = (t == NULL);
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kbt->is_current = is_current;
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if (is_current)
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t = validate_current();
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kbt->task = t;
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kbt->pgtable = NULL;
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kbt->verbose = 0; /* override in caller if desired */
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kbt->profile = 0; /* override in caller if desired */
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kbt->end = KBT_ONGOING;
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kbt->new_context = 0;
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if (is_current) {
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HV_PhysAddr pgdir_pa = hv_inquire_context().page_table;
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if (pgdir_pa == (unsigned long)swapper_pg_dir - PAGE_OFFSET) {
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/*
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* Not just an optimization: this also allows
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* this to work at all before va/pa mappings
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* are set up.
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*/
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kbt->pgtable = swapper_pg_dir;
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} else {
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struct page *page = pfn_to_page(PFN_DOWN(pgdir_pa));
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if (!PageHighMem(page))
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kbt->pgtable = __va(pgdir_pa);
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else
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pr_err("page table not in LOWMEM"
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" (%#llx)\n", pgdir_pa);
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}
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local_flush_tlb_all();
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validate_stack(regs);
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}
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if (regs == NULL) {
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if (is_current || t->state == TASK_RUNNING) {
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/* Can't do this; we need registers */
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kbt->end = KBT_RUNNING;
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return;
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}
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pc = get_switch_to_pc();
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lr = t->thread.pc;
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sp = t->thread.ksp;
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r52 = 0;
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} else {
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pc = regs->pc;
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lr = regs->lr;
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sp = regs->sp;
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r52 = regs->regs[52];
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}
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backtrace_init(&kbt->it, read_memory_func, kbt, pc, lr, sp, r52);
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kbt->end = KBacktraceIterator_next_item_inclusive(kbt);
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}
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EXPORT_SYMBOL(KBacktraceIterator_init);
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int KBacktraceIterator_end(struct KBacktraceIterator *kbt)
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{
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return kbt->end != KBT_ONGOING;
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}
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EXPORT_SYMBOL(KBacktraceIterator_end);
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void KBacktraceIterator_next(struct KBacktraceIterator *kbt)
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{
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unsigned long old_pc = kbt->it.pc, old_sp = kbt->it.sp;
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kbt->new_context = 0;
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if (!backtrace_next(&kbt->it) && !KBacktraceIterator_restart(kbt)) {
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kbt->end = KBT_DONE;
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return;
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}
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kbt->end = KBacktraceIterator_next_item_inclusive(kbt);
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if (old_pc == kbt->it.pc && old_sp == kbt->it.sp) {
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/* Trapped in a loop; give up. */
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kbt->end = KBT_LOOP;
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}
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}
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EXPORT_SYMBOL(KBacktraceIterator_next);
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/*
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* This method wraps the backtracer's more generic support.
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* It is only invoked from the architecture-specific code; show_stack()
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* and dump_stack() (in entry.S) are architecture-independent entry points.
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*/
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void tile_show_stack(struct KBacktraceIterator *kbt, int headers)
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{
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int i;
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if (headers) {
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/*
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* Add a blank line since if we are called from panic(),
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* then bust_spinlocks() spit out a space in front of us
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* and it will mess up our KERN_ERR.
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*/
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pr_err("\n");
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pr_err("Starting stack dump of tid %d, pid %d (%s)"
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" on cpu %d at cycle %lld\n",
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kbt->task->pid, kbt->task->tgid, kbt->task->comm,
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smp_processor_id(), get_cycles());
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}
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kbt->verbose = 1;
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i = 0;
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for (; !KBacktraceIterator_end(kbt); KBacktraceIterator_next(kbt)) {
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char *modname;
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const char *name;
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unsigned long address = kbt->it.pc;
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unsigned long offset, size;
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char namebuf[KSYM_NAME_LEN+100];
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if (address >= PAGE_OFFSET)
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name = kallsyms_lookup(address, &size, &offset,
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&modname, namebuf);
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else
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name = NULL;
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if (!name)
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namebuf[0] = '\0';
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else {
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size_t namelen = strlen(namebuf);
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size_t remaining = (sizeof(namebuf) - 1) - namelen;
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char *p = namebuf + namelen;
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int rc = snprintf(p, remaining, "+%#lx/%#lx ",
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offset, size);
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if (modname && rc < remaining)
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snprintf(p + rc, remaining - rc,
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"[%s] ", modname);
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namebuf[sizeof(namebuf)-1] = '\0';
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}
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pr_err(" frame %d: 0x%lx %s(sp 0x%lx)\n",
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i++, address, namebuf, (unsigned long)(kbt->it.sp));
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if (i >= 100) {
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pr_err("Stack dump truncated"
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" (%d frames)\n", i);
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break;
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}
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}
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if (kbt->end == KBT_LOOP)
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pr_err("Stack dump stopped; next frame identical to this one\n");
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if (headers)
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pr_err("Stack dump complete\n");
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}
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EXPORT_SYMBOL(tile_show_stack);
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/* This is called from show_regs() and _dump_stack() */
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void dump_stack_regs(struct pt_regs *regs)
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{
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struct KBacktraceIterator kbt;
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KBacktraceIterator_init(&kbt, NULL, regs);
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tile_show_stack(&kbt, 1);
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}
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EXPORT_SYMBOL(dump_stack_regs);
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static struct pt_regs *regs_to_pt_regs(struct pt_regs *regs,
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ulong pc, ulong lr, ulong sp, ulong r52)
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{
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memset(regs, 0, sizeof(struct pt_regs));
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regs->pc = pc;
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regs->lr = lr;
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regs->sp = sp;
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regs->regs[52] = r52;
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return regs;
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}
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/* This is called from dump_stack() and just converts to pt_regs */
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void _dump_stack(int dummy, ulong pc, ulong lr, ulong sp, ulong r52)
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{
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struct pt_regs regs;
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dump_stack_regs(regs_to_pt_regs(®s, pc, lr, sp, r52));
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}
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/* This is called from KBacktraceIterator_init_current() */
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void _KBacktraceIterator_init_current(struct KBacktraceIterator *kbt, ulong pc,
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ulong lr, ulong sp, ulong r52)
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{
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struct pt_regs regs;
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KBacktraceIterator_init(kbt, NULL,
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regs_to_pt_regs(®s, pc, lr, sp, r52));
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}
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/* This is called only from kernel/sched.c, with esp == NULL */
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void show_stack(struct task_struct *task, unsigned long *esp)
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{
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struct KBacktraceIterator kbt;
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if (task == NULL || task == current)
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KBacktraceIterator_init_current(&kbt);
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else
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KBacktraceIterator_init(&kbt, task, NULL);
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tile_show_stack(&kbt, 0);
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}
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#ifdef CONFIG_STACKTRACE
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/* Support generic Linux stack API too */
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void save_stack_trace_tsk(struct task_struct *task, struct stack_trace *trace)
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{
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struct KBacktraceIterator kbt;
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int skip = trace->skip;
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int i = 0;
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if (task == NULL || task == current)
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KBacktraceIterator_init_current(&kbt);
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else
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KBacktraceIterator_init(&kbt, task, NULL);
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for (; !KBacktraceIterator_end(&kbt); KBacktraceIterator_next(&kbt)) {
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if (skip) {
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--skip;
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continue;
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}
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if (i >= trace->max_entries || kbt.it.pc < PAGE_OFFSET)
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break;
|
|
trace->entries[i++] = kbt.it.pc;
|
|
}
|
|
trace->nr_entries = i;
|
|
}
|
|
EXPORT_SYMBOL(save_stack_trace_tsk);
|
|
|
|
void save_stack_trace(struct stack_trace *trace)
|
|
{
|
|
save_stack_trace_tsk(NULL, trace);
|
|
}
|
|
|
|
#endif
|
|
|
|
/* In entry.S */
|
|
EXPORT_SYMBOL(KBacktraceIterator_init_current);
|