diff options
Diffstat (limited to 'samples/kprobes/kprobe_example.c')
| -rw-r--r-- | samples/kprobes/kprobe_example.c | 107 |
1 files changed, 68 insertions, 39 deletions
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c index ebf5e0c368ea..53ec6c8b8c40 100644 --- a/samples/kprobes/kprobe_example.c +++ b/samples/kprobes/kprobe_example.c @@ -1,41 +1,63 @@ +// SPDX-License-Identifier: GPL-2.0-only /* - * NOTE: This example is works on x86 and powerpc. * Here's a sample kernel module showing the use of kprobes to dump a - * stack trace and selected registers when do_fork() is called. + * stack trace and selected registers when kernel_clone() is called. * * For more information on theory of operation of kprobes, see - * Documentation/kprobes.txt + * Documentation/trace/kprobes.rst * * You will see the trace data in /var/log/messages and on the console - * whenever do_fork() is invoked to create a new process. + * whenever kernel_clone() is invoked to create a new process. */ +#define pr_fmt(fmt) "%s: " fmt, __func__ + #include <linux/kernel.h> #include <linux/module.h> #include <linux/kprobes.h> +static char symbol[KSYM_NAME_LEN] = "kernel_clone"; +module_param_string(symbol, symbol, KSYM_NAME_LEN, 0644); + /* For each probe you need to allocate a kprobe structure */ static struct kprobe kp = { - .symbol_name = "do_fork", + .symbol_name = symbol, }; /* kprobe pre_handler: called just before the probed instruction is executed */ -static int handler_pre(struct kprobe *p, struct pt_regs *regs) +static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs) { #ifdef CONFIG_X86 - printk(KERN_INFO "pre_handler: p->addr = 0x%p, ip = %lx," - " flags = 0x%lx\n", - p->addr, regs->ip, regs->flags); + pr_info("<%s> p->addr = 0x%p, ip = %lx, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->ip, regs->flags); #endif #ifdef CONFIG_PPC - printk(KERN_INFO "pre_handler: p->addr = 0x%p, nip = 0x%lx," - " msr = 0x%lx\n", - p->addr, regs->nip, regs->msr); + pr_info("<%s> p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n", + p->symbol_name, p->addr, regs->nip, regs->msr); #endif #ifdef CONFIG_MIPS - printk(KERN_INFO "pre_handler: p->addr = 0x%p, epc = 0x%lx," - " status = 0x%lx\n", - p->addr, regs->cp0_epc, regs->cp0_status); + pr_info("<%s> p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n", + p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status); +#endif +#ifdef CONFIG_ARM64 + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, pstate = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate); +#endif +#ifdef CONFIG_ARM + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->ARM_pc, (long)regs->ARM_cpsr); +#endif +#ifdef CONFIG_RISCV + pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n", + p->symbol_name, p->addr, regs->epc, regs->status); +#endif +#ifdef CONFIG_S390 + pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->psw.addr, regs->flags); +#endif +#ifdef CONFIG_LOONGARCH + pr_info("<%s> p->addr = 0x%p, era = 0x%lx, estat = 0x%lx\n", + p->symbol_name, p->addr, regs->csr_era, regs->csr_estat); #endif /* A dump_stack() here will give a stack backtrace */ @@ -43,34 +65,41 @@ static int handler_pre(struct kprobe *p, struct pt_regs *regs) } /* kprobe post_handler: called after the probed instruction is executed */ -static void handler_post(struct kprobe *p, struct pt_regs *regs, +static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs, unsigned long flags) { #ifdef CONFIG_X86 - printk(KERN_INFO "post_handler: p->addr = 0x%p, flags = 0x%lx\n", - p->addr, regs->flags); + pr_info("<%s> p->addr = 0x%p, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->flags); #endif #ifdef CONFIG_PPC - printk(KERN_INFO "post_handler: p->addr = 0x%p, msr = 0x%lx\n", - p->addr, regs->msr); + pr_info("<%s> p->addr = 0x%p, msr = 0x%lx\n", + p->symbol_name, p->addr, regs->msr); #endif #ifdef CONFIG_MIPS - printk(KERN_INFO "post_handler: p->addr = 0x%p, status = 0x%lx\n", - p->addr, regs->cp0_status); + pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n", + p->symbol_name, p->addr, regs->cp0_status); +#endif +#ifdef CONFIG_ARM64 + pr_info("<%s> p->addr = 0x%p, pstate = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->pstate); +#endif +#ifdef CONFIG_ARM + pr_info("<%s> p->addr = 0x%p, cpsr = 0x%lx\n", + p->symbol_name, p->addr, (long)regs->ARM_cpsr); +#endif +#ifdef CONFIG_RISCV + pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n", + p->symbol_name, p->addr, regs->status); +#endif +#ifdef CONFIG_S390 + pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n", + p->symbol_name, p->addr, regs->flags); +#endif +#ifdef CONFIG_LOONGARCH + pr_info("<%s> p->addr = 0x%p, estat = 0x%lx\n", + p->symbol_name, p->addr, regs->csr_estat); #endif -} - -/* - * fault_handler: this is called if an exception is generated for any - * instruction within the pre- or post-handler, or when Kprobes - * single-steps the probed instruction. - */ -static int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr) -{ - printk(KERN_INFO "fault_handler: p->addr = 0x%p, trap #%dn", - p->addr, trapnr); - /* Return 0 because we don't handle the fault. */ - return 0; } static int __init kprobe_init(void) @@ -78,23 +107,23 @@ static int __init kprobe_init(void) int ret; kp.pre_handler = handler_pre; kp.post_handler = handler_post; - kp.fault_handler = handler_fault; ret = register_kprobe(&kp); if (ret < 0) { - printk(KERN_INFO "register_kprobe failed, returned %d\n", ret); + pr_err("register_kprobe failed, returned %d\n", ret); return ret; } - printk(KERN_INFO "Planted kprobe at %p\n", kp.addr); + pr_info("Planted kprobe at %p\n", kp.addr); return 0; } static void __exit kprobe_exit(void) { unregister_kprobe(&kp); - printk(KERN_INFO "kprobe at %p unregistered\n", kp.addr); + pr_info("kprobe at %p unregistered\n", kp.addr); } module_init(kprobe_init) module_exit(kprobe_exit) +MODULE_DESCRIPTION("sample kernel module showing the use of kprobes"); MODULE_LICENSE("GPL"); |