Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * fail_function.c: Function-based error injection
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5) #include <linux/error-injection.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6) #include <linux/debugfs.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7) #include <linux/fault-inject.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8) #include <linux/kallsyms.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9) #include <linux/kprobes.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11) #include <linux/mutex.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12) #include <linux/slab.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) static void fei_post_handler(struct kprobe *kp, struct pt_regs *regs,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) 			     unsigned long flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 	 * A dummy post handler is required to prohibit optimizing, because
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) 	 * jump optimization does not support execution path overriding.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) struct fei_attr {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) 	struct list_head list;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 	struct kprobe kp;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) 	unsigned long retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) static DEFINE_MUTEX(fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) static LIST_HEAD(fei_attr_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) static DECLARE_FAULT_ATTR(fei_fault_attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) static struct dentry *fei_debugfs_dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) static unsigned long adjust_error_retval(unsigned long addr, unsigned long retv)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 	switch (get_injectable_error_type(addr)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) 	case EI_ETYPE_NULL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) 		if (retv != 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) 			return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) 	case EI_ETYPE_ERRNO:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) 		if (retv < (unsigned long)-MAX_ERRNO)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 			return (unsigned long)-EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	case EI_ETYPE_ERRNO_NULL:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 		if (retv != 0 && retv < (unsigned long)-MAX_ERRNO)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 			return (unsigned long)-EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 		break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	return retv;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) static struct fei_attr *fei_attr_new(const char *sym, unsigned long addr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) 	struct fei_attr *attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	attr = kzalloc(sizeof(*attr), GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 	if (attr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 		attr->kp.symbol_name = kstrdup(sym, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 		if (!attr->kp.symbol_name) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 			kfree(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 			return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) 		attr->kp.pre_handler = fei_kprobe_handler;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 		attr->kp.post_handler = fei_post_handler;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) 		attr->retval = adjust_error_retval(addr, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) 		INIT_LIST_HEAD(&attr->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 	return attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) static void fei_attr_free(struct fei_attr *attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 	if (attr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 		kfree(attr->kp.symbol_name);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 		kfree(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) static struct fei_attr *fei_attr_lookup(const char *sym)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) 	struct fei_attr *attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) 	list_for_each_entry(attr, &fei_attr_list, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 		if (!strcmp(attr->kp.symbol_name, sym))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 			return attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 	return NULL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) static bool fei_attr_is_valid(struct fei_attr *_attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	struct fei_attr *attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 	list_for_each_entry(attr, &fei_attr_list, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 		if (attr == _attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 			return true;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 	return false;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) static int fei_retval_set(void *data, u64 val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	struct fei_attr *attr = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	unsigned long retv = (unsigned long)val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) 	mutex_lock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) 	 * Since this operation can be done after retval file is removed,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	 * It is safer to check the attr is still valid before accessing
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) 	 * its member.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) 	if (!fei_attr_is_valid(attr)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) 		err = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	if (attr->kp.addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 		if (adjust_error_retval((unsigned long)attr->kp.addr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) 					val) != retv)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 			err = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) 	if (!err)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130) 		attr->retval = val;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) 	mutex_unlock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) static int fei_retval_get(void *data, u64 *val)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) 	struct fei_attr *attr = data;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) 	int err = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	mutex_lock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 	/* Here we also validate @attr to ensure it still exists. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	if (!fei_attr_is_valid(attr))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		err = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 		*val = attr->retval;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 	mutex_unlock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 	return err;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) DEFINE_DEBUGFS_ATTRIBUTE(fei_retval_ops, fei_retval_get, fei_retval_set,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			 "%llx\n");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) static void fei_debugfs_add_attr(struct fei_attr *attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 	struct dentry *dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 	dir = debugfs_create_dir(attr->kp.symbol_name, fei_debugfs_dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 	debugfs_create_file("retval", 0600, dir, attr, &fei_retval_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) static void fei_debugfs_remove_attr(struct fei_attr *attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	struct dentry *dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	dir = debugfs_lookup(attr->kp.symbol_name, fei_debugfs_dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	debugfs_remove_recursive(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) static int fei_kprobe_handler(struct kprobe *kp, struct pt_regs *regs)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	struct fei_attr *attr = container_of(kp, struct fei_attr, kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	if (should_fail(&fei_fault_attr, 1)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 		regs_set_return_value(regs, attr->retval);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 		override_function_with_return(regs);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 		return 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) NOKPROBE_SYMBOL(fei_kprobe_handler)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186) static void *fei_seq_start(struct seq_file *m, loff_t *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) 	mutex_lock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) 	return seq_list_start(&fei_attr_list, *pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) static void fei_seq_stop(struct seq_file *m, void *v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	mutex_unlock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) static void *fei_seq_next(struct seq_file *m, void *v, loff_t *pos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 	return seq_list_next(v, &fei_attr_list, pos);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) static int fei_seq_show(struct seq_file *m, void *v)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	struct fei_attr *attr = list_entry(v, struct fei_attr, list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	seq_printf(m, "%ps\n", attr->kp.addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) static const struct seq_operations fei_seq_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	.start	= fei_seq_start,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	.next	= fei_seq_next,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	.stop	= fei_seq_stop,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	.show	= fei_seq_show,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static int fei_open(struct inode *inode, struct file *file)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) 	return seq_open(file, &fei_seq_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) static void fei_attr_remove(struct fei_attr *attr)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	fei_debugfs_remove_attr(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	unregister_kprobe(&attr->kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 	list_del(&attr->list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	fei_attr_free(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) static void fei_attr_remove_all(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 	struct fei_attr *attr, *n;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 	list_for_each_entry_safe(attr, n, &fei_attr_list, list) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		fei_attr_remove(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) static ssize_t fei_write(struct file *file, const char __user *buffer,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 			 size_t count, loff_t *ppos)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) 	struct fei_attr *attr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) 	unsigned long addr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) 	char *buf, *sym;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) 	int ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 	/* cut off if it is too long */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	if (count > KSYM_NAME_LEN)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 		count = KSYM_NAME_LEN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 	buf = kmalloc(count + 1, GFP_KERNEL);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 	if (!buf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		return -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	if (copy_from_user(buf, buffer, count)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) 		ret = -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 		goto out_free;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) 	buf[count] = '\0';
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259) 	sym = strstrip(buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) 	mutex_lock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	/* Writing just spaces will remove all injection points */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 	if (sym[0] == '\0') {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 		fei_attr_remove_all();
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		ret = count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	/* Writing !function will remove one injection point */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 	if (sym[0] == '!') {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 		attr = fei_attr_lookup(sym + 1);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 		if (!attr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 			ret = -ENOENT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 			goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 		fei_attr_remove(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		ret = count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 	addr = kallsyms_lookup_name(sym);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 	if (!addr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		ret = -EINVAL;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 	if (!within_error_injection_list(addr)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 		ret = -ERANGE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 	if (fei_attr_lookup(sym)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		ret = -EBUSY;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 	attr = fei_attr_new(sym, addr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) 	if (!attr) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) 		ret = -ENOMEM;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 		goto out;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	ret = register_kprobe(&attr->kp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 	if (!ret)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) 		fei_debugfs_add_attr(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 	if (ret < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) 		fei_attr_remove(attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) 	else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 		list_add_tail(&attr->list, &fei_attr_list);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) 		ret = count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) out:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	mutex_unlock(&fei_lock);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) out_free:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 	kfree(buf);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 	return ret;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) static const struct file_operations fei_ops = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 	.open =		fei_open,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 	.read =		seq_read,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 	.write =	fei_write,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 	.llseek =	seq_lseek,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 	.release =	seq_release,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) static int __init fei_debugfs_init(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) 	struct dentry *dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) 	dir = fault_create_debugfs_attr("fail_function", NULL,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 					&fei_fault_attr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	if (IS_ERR(dir))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 		return PTR_ERR(dir);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	/* injectable attribute is just a symlink of error_inject/list */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	debugfs_create_symlink("injectable", dir, "../error_injection/list");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 	debugfs_create_file("inject", 0600, dir, NULL, &fei_ops);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	fei_debugfs_dir = dir;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) late_initcall(fei_debugfs_init);