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8e2a46a40f
There are several files that I was unable to find a proper place for them, and 3 ones that are still in plain old text format. Let's place those stuff behind the carpet, as we'd like to keep the root directory clean. We can later discuss and move those into better places. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Link: https://lore.kernel.org/r/11bd0d75e65a874f7c276a0aeab0fe13f3376f5f.1592203650.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
120 lines
3.6 KiB
C
120 lines
3.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* NOTE: This example is works on x86 and powerpc.
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* Here's a sample kernel module showing the use of kprobes to dump a
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* stack trace and selected registers when _do_fork() is called.
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*
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* For more information on theory of operation of kprobes, see
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* Documentation/staging/kprobes.rst
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*
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* You will see the trace data in /var/log/messages and on the console
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* whenever _do_fork() is invoked to create a new process.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/kprobes.h>
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#define MAX_SYMBOL_LEN 64
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static char symbol[MAX_SYMBOL_LEN] = "_do_fork";
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module_param_string(symbol, symbol, sizeof(symbol), 0644);
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/* For each probe you need to allocate a kprobe structure */
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static struct kprobe kp = {
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.symbol_name = symbol,
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};
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/* kprobe pre_handler: called just before the probed instruction is executed */
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static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
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{
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#ifdef CONFIG_X86
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pr_info("<%s> pre_handler: p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->ip, regs->flags);
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#endif
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#ifdef CONFIG_PPC
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pr_info("<%s> pre_handler: p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
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p->symbol_name, p->addr, regs->nip, regs->msr);
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#endif
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#ifdef CONFIG_MIPS
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pr_info("<%s> pre_handler: p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status);
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#endif
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#ifdef CONFIG_ARM64
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pr_info("<%s> pre_handler: p->addr = 0x%p, pc = 0x%lx,"
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" pstate = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> pre_handler: p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->psw.addr, regs->flags);
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#endif
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/* A dump_stack() here will give a stack backtrace */
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return 0;
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}
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/* kprobe post_handler: called after the probed instruction is executed */
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static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
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unsigned long flags)
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{
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#ifdef CONFIG_X86
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pr_info("<%s> post_handler: p->addr = 0x%p, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->flags);
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#endif
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#ifdef CONFIG_PPC
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pr_info("<%s> post_handler: p->addr = 0x%p, msr = 0x%lx\n",
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p->symbol_name, p->addr, regs->msr);
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#endif
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#ifdef CONFIG_MIPS
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pr_info("<%s> post_handler: p->addr = 0x%p, status = 0x%lx\n",
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p->symbol_name, p->addr, regs->cp0_status);
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#endif
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#ifdef CONFIG_ARM64
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pr_info("<%s> post_handler: p->addr = 0x%p, pstate = 0x%lx\n",
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p->symbol_name, p->addr, (long)regs->pstate);
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#endif
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#ifdef CONFIG_S390
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pr_info("<%s> pre_handler: p->addr, 0x%p, flags = 0x%lx\n",
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p->symbol_name, p->addr, regs->flags);
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#endif
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}
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/*
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* fault_handler: this is called if an exception is generated for any
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* instruction within the pre- or post-handler, or when Kprobes
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* single-steps the probed instruction.
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*/
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static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
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{
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pr_info("fault_handler: p->addr = 0x%p, trap #%dn", p->addr, trapnr);
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/* Return 0 because we don't handle the fault. */
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return 0;
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}
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/* NOKPROBE_SYMBOL() is also available */
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NOKPROBE_SYMBOL(handler_fault);
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static int __init kprobe_init(void)
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{
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int ret;
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kp.pre_handler = handler_pre;
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kp.post_handler = handler_post;
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kp.fault_handler = handler_fault;
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ret = register_kprobe(&kp);
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if (ret < 0) {
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pr_err("register_kprobe failed, returned %d\n", ret);
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return ret;
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}
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pr_info("Planted kprobe at %p\n", kp.addr);
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return 0;
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}
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static void __exit kprobe_exit(void)
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{
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unregister_kprobe(&kp);
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pr_info("kprobe at %p unregistered\n", kp.addr);
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}
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module_init(kprobe_init)
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module_exit(kprobe_exit)
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MODULE_LICENSE("GPL");
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